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William Link, Ph.D. (Former Employee)

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USFWS Plane

Evaluating the Design of the Waterfowl Breeding Population and Habitat Survey

The Waterfowl Breeding Population and Habitat Survey (WBPHS) is a primary source of waterfowl population status and trend information for management of ducks in North America. The survey has not been reviewed in several decades, and since the last review new analysis approaches and information needs have created a need to reassess the design, scope of inference, and analysis of the survey to...
By
Ecosystems Mission Area, Species Management Research Program, Eastern Ecological Science Center
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Evaluating the Design of the Waterfowl Breeding Population and Habitat Survey

The Waterfowl Breeding Population and Habitat Survey (WBPHS) is a primary source of waterfowl population status and trend information for management of ducks in North America. The survey has not been reviewed in several decades, and since the last review new analysis approaches and information needs have created a need to reassess the design, scope of inference, and analysis of the survey to...
Learn More
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Black Duck, Anas rubripes, Breeding Range Map

Population Change and Abundance of Black Ducks and Mallards in Eastern North America

The boreal forest in the northeastern United States and eastern Canada contains most of the breeding range of the American black duck ( Anas rubripes). We collaborate with scientists from the U. S. Fish and Wildlife Service to design and analyze waterfowl surveys in this large and often inaccessible area.
By
Ecosystems Mission Area, Species Management Research Program, Eastern Ecological Science Center
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Population Change and Abundance of Black Ducks and Mallards in Eastern North America

The boreal forest in the northeastern United States and eastern Canada contains most of the breeding range of the American black duck ( Anas rubripes). We collaborate with scientists from the U. S. Fish and Wildlife Service to design and analyze waterfowl surveys in this large and often inaccessible area.
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BBS Observer along Hughesville, MD BBS route (Photo Credit: Heather Martley)

Implementing Cross Validation Approaches for Model Selection and Evaluating Goodness of Fit in Complex Hierarchical Models

It is (relatively) easy to construct complex hierarchical models for analysis of the North American Breeding Bird Survey (BBS), but deciding which model best describes population change is difficult. We are developing methods for model selection for BBS and other important survey data sets, and using them to refine our estimates of population change from this important survey.
By
Ecosystems Mission Area, Species Management Research Program, Eastern Ecological Science Center
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Implementing Cross Validation Approaches for Model Selection and Evaluating Goodness of Fit in Complex Hierarchical Models

It is (relatively) easy to construct complex hierarchical models for analysis of the North American Breeding Bird Survey (BBS), but deciding which model best describes population change is difficult. We are developing methods for model selection for BBS and other important survey data sets, and using them to refine our estimates of population change from this important survey.
Learn More
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Population Change and the BBS

Design and Analysis of Surveys for Estimation of Temporal and Spatial Change in Animal Populations

Designing and analyzing large-scale animal surveys is an important focus of our research. Although we conduct research into analysis methods for many surveys, the primary focus of this project is to conduct analyses and develop web-based summaries of data from the North American Breeding Bird Survey (BBS).
By
Ecosystems Mission Area, Species Management Research Program, Eastern Ecological Science Center
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Design and Analysis of Surveys for Estimation of Temporal and Spatial Change in Animal Populations

Designing and analyzing large-scale animal surveys is an important focus of our research. Although we conduct research into analysis methods for many surveys, the primary focus of this project is to conduct analyses and develop web-based summaries of data from the North American Breeding Bird Survey (BBS).
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Weddell seal pup and mom

Hierarchical Models for Estimation of Population Parameters

The Challenge: Much of wildlife research consists of the description of variation in data. Some of the variation results from spatial and temporal change in populations, while some results from biologically irrelevant sampling variation induced by the process of data collection. Distinguishing relevant from irrelevant variation is the first task of statistical analysis, but the job does not end...
By
Ecosystems Mission Area, Species Management Research Program, Eastern Ecological Science Center
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Hierarchical Models for Estimation of Population Parameters

The Challenge: Much of wildlife research consists of the description of variation in data. Some of the variation results from spatial and temporal change in populations, while some results from biologically irrelevant sampling variation induced by the process of data collection. Distinguishing relevant from irrelevant variation is the first task of statistical analysis, but the job does not end...
Learn More
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Dwarf crocodiles, Osteolaemus tetraspis

Development of Statistical Methods for Biological Applications

The Challenge: Wildlife science and management are guided by data, and it is unquestionably the case that the greatest success occurs when good data are analyzed by good statistical methods.
By
Ecosystems Mission Area, Species Management Research Program, Eastern Ecological Science Center
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Development of Statistical Methods for Biological Applications

The Challenge: Wildlife science and management are guided by data, and it is unquestionably the case that the greatest success occurs when good data are analyzed by good statistical methods.
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Feral cat in trap.

Managing Free-Roaming Cats at the Patuxent Research Refuge

The Challenge: Free-roaming cats (Felis catus) are nonnative predators of small mammals, songbirds and gamebirds, reptiles, amphibians, and insects. They are also competitors of native predators and vectors for diseases to human and wildlife. The US Fish and Wildlife Service is authorized to remove cats from National Wildlife Refuges. Presently cat trapping on Refuge lands is conducted...
By
Ecosystems Mission Area, Species Management Research Program, Eastern Ecological Science Center
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Managing Free-Roaming Cats at the Patuxent Research Refuge

The Challenge: Free-roaming cats (Felis catus) are nonnative predators of small mammals, songbirds and gamebirds, reptiles, amphibians, and insects. They are also competitors of native predators and vectors for diseases to human and wildlife. The US Fish and Wildlife Service is authorized to remove cats from National Wildlife Refuges. Presently cat trapping on Refuge lands is conducted...
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Vultures unintentionally ingested diclofenac when scavenging livestock treated shortly before death.

Toxicity of the Non-Steroidal Anti-Inflammatory Drug Diclofenac

One of the hallmarks of non-steroidal anti-inflammatory drugs (NSAID) is the difficulty in predicting potentially toxic effects.Diclofenac is one such NSAID that devastated Asian vulture populations when they fed upon carcasses of livestock treated with the NSAID diclofenac.Because these drugs are widely used, we studied the potential hazard of diclofenac in New World vultures.
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Ecosystems Mission Area, Contaminant Biology, Eastern Ecological Science Center
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Toxicity of the Non-Steroidal Anti-Inflammatory Drug Diclofenac

One of the hallmarks of non-steroidal anti-inflammatory drugs (NSAID) is the difficulty in predicting potentially toxic effects.Diclofenac is one such NSAID that devastated Asian vulture populations when they fed upon carcasses of livestock treated with the NSAID diclofenac.Because these drugs are widely used, we studied the potential hazard of diclofenac in New World vultures.
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Data for "Population Dynamics and Harvest Management of Eastern Mallards"

Data and R Code for manuscript titled "Population Dynamics and Harvest Management of Eastern Mallards"
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Eastern Ecological Science Center

The North American Breeding Bird Survey, Analysis Results 1966 - 2021

This data product consists of a database of population change and abundance estimates for North American birds, estimated from North American Breeding Bird Survey (BBS) data. Data are presented for 548 species of birds in 4 spreadsheets containing trend estimates and annual indices for 2 time periods. Estimates are derived for each species using the 1 of 4 alternative models, and a cross...
By
Eastern Ecological Science Center

Phenology effects in the North American Breeding Bird Survey

This data product provides summary information, by species, of changes in relative visibility of birds (phenology effects) through the April - July time period in which the North American Breeding Bird Survey (BBS) is conducted. Data are presented for 408 species of birds. Seasonal phenology effects are presented for selected latitudes and years, documenting changes in visibility and a...
By
Eastern Ecological Science Center

The North American Breeding Bird Survey, Analysis Results 1966 - 2019

This data product consists of a database of population change and abundance estimates for North American birds, estimated from North American Breeding Bird Survey (BBS) data. Data are presented for 548 species of birds in 4 spreadsheets containing trend estimates and annual indices for 2 time periods. Estimates are derived for each species using the 1 of 4 alternative models, and a cross...
By
Species Management Research Program, Eastern Ecological Science Center

The North American Breeding Bird Survey, Analysis Results 1966 - 2018

This data product consists of a database of population change and abundance estimates for North American birds, estimated from North American Breeding Bird Survey (BBS) data. Data are presented for 548 species of birds in 4 spreadsheets containing trend estimates and annual indices for 2 time periods. Estimates are derived for each species using the 1 of 4 alternative models, and a cross...
By
Eastern Ecological Science Center

The North American Breeding Bird Survey, Analysis Results 1966 - 2017

This data product consists of a database of population change and relative abundance estimates for North American birds, estimated from North American Breeding Bird Survey (BBS) data. Data are presented in 6 separate spreadsheets for 2 methods of trend summary and 3 time periods for 548 species of birds. Metadata for the BBS data used to produce these estimates is available from a USGS...
By
Species Management Research Program, Eastern Ecological Science Center
Filter Total Items: 44
Image: Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Photo by USGS scientist William A Link at Erebus Bay, Antarctica.  Images were obtained under NMFS Permit No: 1032-1917.  

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Photo by USGS scientist William A Link at Erebus Bay, Antarctica.  Images were obtained under NMFS Permit No: 1032-1917.  

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Pup rests in the snow.  Images were obtained under NMFS Permit No: 1032-1917.  

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Pup rests in the snow.  Images were obtained under NMFS Permit No: 1032-1917.  

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Pup playfully greets mother in the snow.

Photo by USGS scientist William A Link at Erebus Bay, Antarctica.  Images were obtained under NMFS Permit No: 1032-1917. 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Pup playfully greets mother in the snow.

Photo by USGS scientist William A Link at Erebus Bay, Antarctica.  Images were obtained under NMFS Permit No: 1032-1917. 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Uncommon set of seal twins. Images were obtained under NMFS Permit No: 1032-1917. 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Uncommon set of seal twins. Images were obtained under NMFS Permit No: 1032-1917. 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Baby seal rests on its side in the snow. Images were obtained under NMFS Permit No: 1032-1917. 

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Baby seal rests on its side in the snow. Images were obtained under NMFS Permit No: 1032-1917. 

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Baby seal rests on its side in the snow. Images were obtained under NMFS Permit No: 1032-1917. 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Baby seal rests on its side in the snow. Images were obtained under NMFS Permit No: 1032-1917. 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Principal investiigator Dr Jay Rotella of Montana State University. Images were obtained under NMFS Permit No: 1032-1917.

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Principal investiigator Dr Jay Rotella of Montana State University. Images were obtained under NMFS Permit No: 1032-1917.

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Mount Erebus in background.  Little Razorback (left) and Big Razorback (right) islands are sites of seal colonies. Images were obtained under NMFS Permit No: 1032-1917.

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Mount Erebus in background.  Little Razorback (left) and Big Razorback (right) islands are sites of seal colonies. Images were obtained under NMFS Permit No: 1032-1917.

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Mount Erebus in background.  Images were obtained under NMFS Permit No: 1032-1917. 

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Mount Erebus in background.  Images were obtained under NMFS Permit No: 1032-1917. 

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Photo by USGS scientist William A Link at Erebus Bay, Antarctica.  Images were obtained under NMFS Permit No: 1032-1917. 

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Photo by USGS scientist William A Link at Erebus Bay, Antarctica.  Images were obtained under NMFS Permit No: 1032-1917. 

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Baby seal rests on its side in the snow. Images were obtained under NMFS Permit No: 1032-1917.

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Baby seal rests on its side in the snow. Images were obtained under NMFS Permit No: 1032-1917.

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Two seals in swimming lessons. Images were obtained under NMFS Permit No: 1032-1917. 

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Two seals in swimming lessons. Images were obtained under NMFS Permit No: 1032-1917. 

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Photo by USGS scientist William A Link at Erebus Bay, Antarctica.  Images were obtained under NMFS Permit No: 1032-1917.

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Photo by USGS scientist William A Link at Erebus Bay, Antarctica.  Images were obtained under NMFS Permit No: 1032-1917.

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Swimming lessons.  Note shaved ice in front of mom (right): she's been enlarging the hole with her teeth. Images were obtained under NMFS Permit No: 1032-1917. 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Swimming lessons.  Note shaved ice in front of mom (right): she's been enlarging the hole with her teeth. Images were obtained under NMFS Permit No: 1032-1917. 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Aerial photo of field camp, 12 miles from McMurdo station. Images were obtained under NMFS Permit No: 1032-1917. 

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Aerial photo of field camp, 12 miles from McMurdo station. Images were obtained under NMFS Permit No: 1032-1917. 

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Terminus of Mt. Erebus glacial tongue. Images were obtained under NMFS Permit No: 1032-1917. 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Terminus of Mt. Erebus glacial tongue. Images were obtained under NMFS Permit No: 1032-1917. 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weighing female seal, while pup waits. (Mom weighed 1115 pounds.) Images were obtained under NMFS Permit No: 1032-1917. 

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weighing female seal, while pup waits. (Mom weighed 1115 pounds.) Images were obtained under NMFS Permit No: 1032-1917. 

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Mount Erebus in background of Inaccessible Island. Images were obtained under NMFS Permit No: 1032-1917.  

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Mount Erebus in background of Inaccessible Island. Images were obtained under NMFS Permit No: 1032-1917.  

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Young pup's lanugo fur makes a soft pillow for mom.

Photo by USGS scientist William A Link at Erebus Bay, Antarctica.  Images were obtained under NMFS Permit No: 1032-1917. 

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Young pup's lanugo fur makes a soft pillow for mom.

Photo by USGS scientist William A Link at Erebus Bay, Antarctica.  Images were obtained under NMFS Permit No: 1032-1917. 

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Photo by USGS scientist William A Link at Erebus Bay, Antarctica.  Images were obtained under NMFS Permit No: 1032-1917.

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Photo by USGS scientist William A Link at Erebus Bay, Antarctica.  Images were obtained under NMFS Permit No: 1032-1917.

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Photo by USGS scientist William A Link at Erebus Bay, Antarctica.  Images were obtained under NMFS Permit No: 1032-1917. 

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Photo by USGS scientist William A Link at Erebus Bay, Antarctica.  Images were obtained under NMFS Permit No: 1032-1917. 

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Filter Total Items: 122

Population dynamics and harvest management of eastern mallards

Managing sustainable harvest of wildlife populations requires regular collection of demographic data and robust estimates of demographic parameters. Estimates can then be used to develop a harvest strategy to guide decision-making. Mallards (Anas platyrhynchos) are an important species in the Atlantic Flyway for many users and they exhibited exponential growth in the eastern United...
Authors
Anthony J. Roberts, Jeffrey A. Hostetler, Joshua C. Stiller, Patrick K. Devers, William Link
By
Ecosystems Mission Area, Eastern Ecological Science Center

American Woodcock singing-ground survey: Comparison of four models for trend in population size

Wildlife biologists monitor the status and trends of American woodcock Scolopax minor populations in the eastern and central United States and Canada via a singing-ground survey, conducted just after sunset along roadsides in spring. Annual analyses of the survey produce estimates of trend and annual indexes of abundance for 25 states and provinces, management regions, and survey-wide...
Authors
John R. Sauer, William Link, Mark E Seamans, Rebecca D. Rau
By
Ecosystems Mission Area, Eastern Ecological Science Center

A Bayesian Dirichlet process community occupancy model to estimate community structure and species similarity

Community occupancy models estimate species‐specific parameters while sharing information across species by treating parameters as sampled from a common distribution. When communities consist of discrete groups, shrinkage of estimates towards the community mean can mask differences among groups. Infinite mixture models using a Dirichlet process (DP) distribution, in which the number of...
Authors
Rahel Sollmann, Mitchell Eaton, William Link, Paul Mulundo, Samuel Ayebare, Sarah Prinsloo, Andrew J. Plumptre, D.S. Johnson
By
Ecosystems Mission Area, Climate Adaptation Science Centers

Sources of variation in maternal allocation in a long-lived mammal

1.Life history theory predicts allocation of energy to reproduction varies with maternal age, but additional maternal features may be important to the allocation of energy to reproduction.We aimed to characterize age‐specific variation in maternal allocation and assess the relationship between maternal allocation and other static and dynamic maternal features.Mass measurements of 531...
Authors
Kaitlin R. Macdonald, Jay J. Rotella, Robert A. Garrott, William A. Link
By
Ecosystems Mission Area, Eastern Ecological Science Center

Model selection for the North American Breeding Bird Survey

The North American Breeding Bird Survey (BBS) provides data that can be used in complex, multiscale analyses of population change, while controlling for scale‐specific nuisance factors. Many alternative models can be fit to the data, but most model selection procedures are not appropriate for hierarchical models. Leave‐one‐out cross‐validation (LOOCV), in which relative model fit is...
Authors
William A. Link, John R. Sauer, Daniel K Niven
By
Ecosystems Mission Area, Eastern Ecological Science Center

Variation of annual apparent survival and detection rates with age, year, and individual identity in male Weddell seals (Leptonychotes weddellii) from long-term mark-recapture data

Exploring age- and sex-specific survival rates provides insight regarding population behavior and life-history trait evolution, but many population studies exclude males. Accordingly, our understanding of how age-specific patterns of survival, including actuarial senescence, compare between the sexes remains inadequate. Using 35 years of mark-recapture data for 7,516 male Weddell seals...
Authors
Jamie L. Brusa, Jay J. Rotella, Robert A. Garrott, J. Terrill Paterson, William Link
By
Ecosystems Mission Area, Eastern Ecological Science Center

Consistency counts: Modeling the effects of a change in protocol on Breeding Bird Survey counts

Analysis of North American Breeding Bird Survey (BBS) data requires controls for factors that influence detectability of birds along survey routes. Identifying factors that influence the counting process and incorporating them into analyses is a primary means of limiting bias in estimates of population change. Twedt (2015) implemented an alternative counting protocol on operational and...
Authors
John R. Sauer, William A. Link, David Ziolkowski, Keith L. Pardieck, Daniel J. Twedt
By
Ecosystems Mission Area, Eastern Ecological Science Center

Analysis of population change and movement using robust design removal data

In capture-mark-reencounter studies, Pollock’s robust design combines methods for open populations with methods for closed populations. Open population features of the robust design allow for estimation of rates of death or permanent emigration, and closed population features enhance estimation of population sizes. We describe a similar design, but for use with removal data. Data...
Authors
William A. Link, Sarah J. Converse, Amy A. Yackel Adams, Nathan J. Hostetter
By
Ecosystems Mission Area, Eastern Ecological Science Center

Variation in the vital rates of an Antarctic marine predator: the role of individual heterogeneity

Variation in life‐history traits such as lifespan and lifetime reproductive output is thought to arise, in part, due to among‐individual differences in the underlying probabilities of survival and reproduction. However, the stochastic nature of demographic processes can also generate considerable variation in fitness‐related traits among otherwise‐identical individuals. An improved...
Authors
J. Terrill Paterson, Jay J. Rotella, William A. Link, Robert A. Garrott
By
Ecosystems Mission Area, Eastern Ecological Science Center

On the reliability of N‐mixture models for count data

N‐mixture models describe count data replicated in time and across sites in terms of abundance N and detectability p. They are popular because they allow inference about N while controlling for factors that influence p without the need for marking animals. Using a capture–recapture perspective, we show that the loss of information that results from not marking animals is critical, making...
Authors
Richard J. Barker, Matthew J. Schofield, William A. Link, John R. Sauer
By
Ecosystems Mission Area, Eastern Ecological Science Center

On the robustness of N‐mixture models

N‐mixture models provide an appealing alternative to mark–recapture models, in that they allow for estimation of detection probability and population size from count data, without requiring that individual animals be identified. There is, however, a cost to using the N‐mixture models: inference is very sensitive to the model's assumptions. We consider the effects of three violations of...
Authors
William A. Link, Matthew R. Schofield, Richard J. Barker, John R. Sauer
By
Ecosystems Mission Area, Eastern Ecological Science Center

Model selection for the North American Breeding Bird Survey: A comparison of methods

The North American Breeding Bird Survey (BBS) provides data for >420 bird species at multiple geographic scales over 5 decades. Modern computational methods have facilitated the fitting of complex hierarchical models to these data. It is easy to propose and fit new models, but little attention has been given to model selection. Here, we discuss and illustrate model selection using leave...
Authors
William A. Link, John R. Sauer, Daniel Niven
By
Ecosystems Mission Area, Eastern Ecological Science Center

Identifying Pareto-efficient eradication strategies for invasive populations

Invasive species are a major cause of biodiversity loss and are notoriously expensive and challenging to manage. We developed a decision-analytic framework for evaluating invasive species removal strategies, given objectives of maximizing eradication probability and minimizing costs. The framework uses an existing estimation model for spatially referenced removal data – one of the most...
By
Fort Collins Science Center

Science and Products

link
USFWS Plane

Evaluating the Design of the Waterfowl Breeding Population and Habitat Survey

The Waterfowl Breeding Population and Habitat Survey (WBPHS) is a primary source of waterfowl population status and trend information for management of ducks in North America. The survey has not been reviewed in several decades, and since the last review new analysis approaches and information needs have created a need to reassess the design, scope of inference, and analysis of the survey to...
By
Ecosystems Mission Area, Species Management Research Program, Eastern Ecological Science Center
link

Evaluating the Design of the Waterfowl Breeding Population and Habitat Survey

The Waterfowl Breeding Population and Habitat Survey (WBPHS) is a primary source of waterfowl population status and trend information for management of ducks in North America. The survey has not been reviewed in several decades, and since the last review new analysis approaches and information needs have created a need to reassess the design, scope of inference, and analysis of the survey to...
Learn More
link
Black Duck, Anas rubripes, Breeding Range Map

Population Change and Abundance of Black Ducks and Mallards in Eastern North America

The boreal forest in the northeastern United States and eastern Canada contains most of the breeding range of the American black duck ( Anas rubripes). We collaborate with scientists from the U. S. Fish and Wildlife Service to design and analyze waterfowl surveys in this large and often inaccessible area.
By
Ecosystems Mission Area, Species Management Research Program, Eastern Ecological Science Center
link

Population Change and Abundance of Black Ducks and Mallards in Eastern North America

The boreal forest in the northeastern United States and eastern Canada contains most of the breeding range of the American black duck ( Anas rubripes). We collaborate with scientists from the U. S. Fish and Wildlife Service to design and analyze waterfowl surveys in this large and often inaccessible area.
Learn More
link
BBS Observer along Hughesville, MD BBS route (Photo Credit: Heather Martley)

Implementing Cross Validation Approaches for Model Selection and Evaluating Goodness of Fit in Complex Hierarchical Models

It is (relatively) easy to construct complex hierarchical models for analysis of the North American Breeding Bird Survey (BBS), but deciding which model best describes population change is difficult. We are developing methods for model selection for BBS and other important survey data sets, and using them to refine our estimates of population change from this important survey.
By
Ecosystems Mission Area, Species Management Research Program, Eastern Ecological Science Center
link

Implementing Cross Validation Approaches for Model Selection and Evaluating Goodness of Fit in Complex Hierarchical Models

It is (relatively) easy to construct complex hierarchical models for analysis of the North American Breeding Bird Survey (BBS), but deciding which model best describes population change is difficult. We are developing methods for model selection for BBS and other important survey data sets, and using them to refine our estimates of population change from this important survey.
Learn More
link
Population Change and the BBS

Design and Analysis of Surveys for Estimation of Temporal and Spatial Change in Animal Populations

Designing and analyzing large-scale animal surveys is an important focus of our research. Although we conduct research into analysis methods for many surveys, the primary focus of this project is to conduct analyses and develop web-based summaries of data from the North American Breeding Bird Survey (BBS).
By
Ecosystems Mission Area, Species Management Research Program, Eastern Ecological Science Center
link

Design and Analysis of Surveys for Estimation of Temporal and Spatial Change in Animal Populations

Designing and analyzing large-scale animal surveys is an important focus of our research. Although we conduct research into analysis methods for many surveys, the primary focus of this project is to conduct analyses and develop web-based summaries of data from the North American Breeding Bird Survey (BBS).
Learn More
link
Weddell seal pup and mom

Hierarchical Models for Estimation of Population Parameters

The Challenge: Much of wildlife research consists of the description of variation in data. Some of the variation results from spatial and temporal change in populations, while some results from biologically irrelevant sampling variation induced by the process of data collection. Distinguishing relevant from irrelevant variation is the first task of statistical analysis, but the job does not end...
By
Ecosystems Mission Area, Species Management Research Program, Eastern Ecological Science Center
link

Hierarchical Models for Estimation of Population Parameters

The Challenge: Much of wildlife research consists of the description of variation in data. Some of the variation results from spatial and temporal change in populations, while some results from biologically irrelevant sampling variation induced by the process of data collection. Distinguishing relevant from irrelevant variation is the first task of statistical analysis, but the job does not end...
Learn More
link
Dwarf crocodiles, Osteolaemus tetraspis

Development of Statistical Methods for Biological Applications

The Challenge: Wildlife science and management are guided by data, and it is unquestionably the case that the greatest success occurs when good data are analyzed by good statistical methods.
By
Ecosystems Mission Area, Species Management Research Program, Eastern Ecological Science Center
link

Development of Statistical Methods for Biological Applications

The Challenge: Wildlife science and management are guided by data, and it is unquestionably the case that the greatest success occurs when good data are analyzed by good statistical methods.
Learn More
link
Feral cat in trap.

Managing Free-Roaming Cats at the Patuxent Research Refuge

The Challenge: Free-roaming cats (Felis catus) are nonnative predators of small mammals, songbirds and gamebirds, reptiles, amphibians, and insects. They are also competitors of native predators and vectors for diseases to human and wildlife. The US Fish and Wildlife Service is authorized to remove cats from National Wildlife Refuges. Presently cat trapping on Refuge lands is conducted...
By
Ecosystems Mission Area, Species Management Research Program, Eastern Ecological Science Center
link

Managing Free-Roaming Cats at the Patuxent Research Refuge

The Challenge: Free-roaming cats (Felis catus) are nonnative predators of small mammals, songbirds and gamebirds, reptiles, amphibians, and insects. They are also competitors of native predators and vectors for diseases to human and wildlife. The US Fish and Wildlife Service is authorized to remove cats from National Wildlife Refuges. Presently cat trapping on Refuge lands is conducted...
Learn More
link
Vultures unintentionally ingested diclofenac when scavenging livestock treated shortly before death.

Toxicity of the Non-Steroidal Anti-Inflammatory Drug Diclofenac

One of the hallmarks of non-steroidal anti-inflammatory drugs (NSAID) is the difficulty in predicting potentially toxic effects.Diclofenac is one such NSAID that devastated Asian vulture populations when they fed upon carcasses of livestock treated with the NSAID diclofenac.Because these drugs are widely used, we studied the potential hazard of diclofenac in New World vultures.
By
Ecosystems Mission Area, Contaminant Biology, Eastern Ecological Science Center
link

Toxicity of the Non-Steroidal Anti-Inflammatory Drug Diclofenac

One of the hallmarks of non-steroidal anti-inflammatory drugs (NSAID) is the difficulty in predicting potentially toxic effects.Diclofenac is one such NSAID that devastated Asian vulture populations when they fed upon carcasses of livestock treated with the NSAID diclofenac.Because these drugs are widely used, we studied the potential hazard of diclofenac in New World vultures.
Learn More

Data for "Population Dynamics and Harvest Management of Eastern Mallards"

Data and R Code for manuscript titled "Population Dynamics and Harvest Management of Eastern Mallards"
By
Eastern Ecological Science Center

The North American Breeding Bird Survey, Analysis Results 1966 - 2021

This data product consists of a database of population change and abundance estimates for North American birds, estimated from North American Breeding Bird Survey (BBS) data. Data are presented for 548 species of birds in 4 spreadsheets containing trend estimates and annual indices for 2 time periods. Estimates are derived for each species using the 1 of 4 alternative models, and a cross...
By
Eastern Ecological Science Center

Phenology effects in the North American Breeding Bird Survey

This data product provides summary information, by species, of changes in relative visibility of birds (phenology effects) through the April - July time period in which the North American Breeding Bird Survey (BBS) is conducted. Data are presented for 408 species of birds. Seasonal phenology effects are presented for selected latitudes and years, documenting changes in visibility and a...
By
Eastern Ecological Science Center

The North American Breeding Bird Survey, Analysis Results 1966 - 2019

This data product consists of a database of population change and abundance estimates for North American birds, estimated from North American Breeding Bird Survey (BBS) data. Data are presented for 548 species of birds in 4 spreadsheets containing trend estimates and annual indices for 2 time periods. Estimates are derived for each species using the 1 of 4 alternative models, and a cross...
By
Species Management Research Program, Eastern Ecological Science Center

The North American Breeding Bird Survey, Analysis Results 1966 - 2018

This data product consists of a database of population change and abundance estimates for North American birds, estimated from North American Breeding Bird Survey (BBS) data. Data are presented for 548 species of birds in 4 spreadsheets containing trend estimates and annual indices for 2 time periods. Estimates are derived for each species using the 1 of 4 alternative models, and a cross...
By
Eastern Ecological Science Center

The North American Breeding Bird Survey, Analysis Results 1966 - 2017

This data product consists of a database of population change and relative abundance estimates for North American birds, estimated from North American Breeding Bird Survey (BBS) data. Data are presented in 6 separate spreadsheets for 2 methods of trend summary and 3 time periods for 548 species of birds. Metadata for the BBS data used to produce these estimates is available from a USGS...
By
Species Management Research Program, Eastern Ecological Science Center
Filter Total Items: 44
Image: Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Photo by USGS scientist William A Link at Erebus Bay, Antarctica.  Images were obtained under NMFS Permit No: 1032-1917.  

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Photo by USGS scientist William A Link at Erebus Bay, Antarctica.  Images were obtained under NMFS Permit No: 1032-1917.  

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Pup rests in the snow.  Images were obtained under NMFS Permit No: 1032-1917.  

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Pup rests in the snow.  Images were obtained under NMFS Permit No: 1032-1917.  

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Pup playfully greets mother in the snow.

Photo by USGS scientist William A Link at Erebus Bay, Antarctica.  Images were obtained under NMFS Permit No: 1032-1917. 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Pup playfully greets mother in the snow.

Photo by USGS scientist William A Link at Erebus Bay, Antarctica.  Images were obtained under NMFS Permit No: 1032-1917. 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Uncommon set of seal twins. Images were obtained under NMFS Permit No: 1032-1917. 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Uncommon set of seal twins. Images were obtained under NMFS Permit No: 1032-1917. 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Baby seal rests on its side in the snow. Images were obtained under NMFS Permit No: 1032-1917. 

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Baby seal rests on its side in the snow. Images were obtained under NMFS Permit No: 1032-1917. 

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Baby seal rests on its side in the snow. Images were obtained under NMFS Permit No: 1032-1917. 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Baby seal rests on its side in the snow. Images were obtained under NMFS Permit No: 1032-1917. 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Principal investiigator Dr Jay Rotella of Montana State University. Images were obtained under NMFS Permit No: 1032-1917.

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Principal investiigator Dr Jay Rotella of Montana State University. Images were obtained under NMFS Permit No: 1032-1917.

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Mount Erebus in background.  Little Razorback (left) and Big Razorback (right) islands are sites of seal colonies. Images were obtained under NMFS Permit No: 1032-1917.

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Mount Erebus in background.  Little Razorback (left) and Big Razorback (right) islands are sites of seal colonies. Images were obtained under NMFS Permit No: 1032-1917.

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Mount Erebus in background.  Images were obtained under NMFS Permit No: 1032-1917. 

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Mount Erebus in background.  Images were obtained under NMFS Permit No: 1032-1917. 

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Photo by USGS scientist William A Link at Erebus Bay, Antarctica.  Images were obtained under NMFS Permit No: 1032-1917. 

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Photo by USGS scientist William A Link at Erebus Bay, Antarctica.  Images were obtained under NMFS Permit No: 1032-1917. 

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Baby seal rests on its side in the snow. Images were obtained under NMFS Permit No: 1032-1917.

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Baby seal rests on its side in the snow. Images were obtained under NMFS Permit No: 1032-1917.

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Two seals in swimming lessons. Images were obtained under NMFS Permit No: 1032-1917. 

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Two seals in swimming lessons. Images were obtained under NMFS Permit No: 1032-1917. 

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Photo by USGS scientist William A Link at Erebus Bay, Antarctica.  Images were obtained under NMFS Permit No: 1032-1917.

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Photo by USGS scientist William A Link at Erebus Bay, Antarctica.  Images were obtained under NMFS Permit No: 1032-1917.

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Swimming lessons.  Note shaved ice in front of mom (right): she's been enlarging the hole with her teeth. Images were obtained under NMFS Permit No: 1032-1917. 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Swimming lessons.  Note shaved ice in front of mom (right): she's been enlarging the hole with her teeth. Images were obtained under NMFS Permit No: 1032-1917. 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Aerial photo of field camp, 12 miles from McMurdo station. Images were obtained under NMFS Permit No: 1032-1917. 

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Aerial photo of field camp, 12 miles from McMurdo station. Images were obtained under NMFS Permit No: 1032-1917. 

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Terminus of Mt. Erebus glacial tongue. Images were obtained under NMFS Permit No: 1032-1917. 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Terminus of Mt. Erebus glacial tongue. Images were obtained under NMFS Permit No: 1032-1917. 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weighing female seal, while pup waits. (Mom weighed 1115 pounds.) Images were obtained under NMFS Permit No: 1032-1917. 

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weighing female seal, while pup waits. (Mom weighed 1115 pounds.) Images were obtained under NMFS Permit No: 1032-1917. 

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Mount Erebus in background of Inaccessible Island. Images were obtained under NMFS Permit No: 1032-1917.  

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Mount Erebus in background of Inaccessible Island. Images were obtained under NMFS Permit No: 1032-1917.  

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Young pup's lanugo fur makes a soft pillow for mom.

Photo by USGS scientist William A Link at Erebus Bay, Antarctica.  Images were obtained under NMFS Permit No: 1032-1917. 

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Young pup's lanugo fur makes a soft pillow for mom.

Photo by USGS scientist William A Link at Erebus Bay, Antarctica.  Images were obtained under NMFS Permit No: 1032-1917. 

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Photo by USGS scientist William A Link at Erebus Bay, Antarctica.  Images were obtained under NMFS Permit No: 1032-1917.

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Photo by USGS scientist William A Link at Erebus Bay, Antarctica.  Images were obtained under NMFS Permit No: 1032-1917.

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Weddell Seal Research at Erebus Bay, Antarctica
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Photo by USGS scientist William A Link at Erebus Bay, Antarctica.  Images were obtained under NMFS Permit No: 1032-1917. 

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Image: Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Weddell Seal Research at Erebus Bay, Antarctica

Photo by USGS scientist William A Link at Erebus Bay, Antarctica.  Images were obtained under NMFS Permit No: 1032-1917. 

 

 

By
Patuxent Wildlife Research Center, Eastern Ecological Science Center, Communications and Publishing
Filter Total Items: 122

Population dynamics and harvest management of eastern mallards

Managing sustainable harvest of wildlife populations requires regular collection of demographic data and robust estimates of demographic parameters. Estimates can then be used to develop a harvest strategy to guide decision-making. Mallards (Anas platyrhynchos) are an important species in the Atlantic Flyway for many users and they exhibited exponential growth in the eastern United...
Authors
Anthony J. Roberts, Jeffrey A. Hostetler, Joshua C. Stiller, Patrick K. Devers, William Link
By
Ecosystems Mission Area, Eastern Ecological Science Center

American Woodcock singing-ground survey: Comparison of four models for trend in population size

Wildlife biologists monitor the status and trends of American woodcock Scolopax minor populations in the eastern and central United States and Canada via a singing-ground survey, conducted just after sunset along roadsides in spring. Annual analyses of the survey produce estimates of trend and annual indexes of abundance for 25 states and provinces, management regions, and survey-wide...
Authors
John R. Sauer, William Link, Mark E Seamans, Rebecca D. Rau
By
Ecosystems Mission Area, Eastern Ecological Science Center

A Bayesian Dirichlet process community occupancy model to estimate community structure and species similarity

Community occupancy models estimate species‐specific parameters while sharing information across species by treating parameters as sampled from a common distribution. When communities consist of discrete groups, shrinkage of estimates towards the community mean can mask differences among groups. Infinite mixture models using a Dirichlet process (DP) distribution, in which the number of...
Authors
Rahel Sollmann, Mitchell Eaton, William Link, Paul Mulundo, Samuel Ayebare, Sarah Prinsloo, Andrew J. Plumptre, D.S. Johnson
By
Ecosystems Mission Area, Climate Adaptation Science Centers

Sources of variation in maternal allocation in a long-lived mammal

1.Life history theory predicts allocation of energy to reproduction varies with maternal age, but additional maternal features may be important to the allocation of energy to reproduction.We aimed to characterize age‐specific variation in maternal allocation and assess the relationship between maternal allocation and other static and dynamic maternal features.Mass measurements of 531...
Authors
Kaitlin R. Macdonald, Jay J. Rotella, Robert A. Garrott, William A. Link
By
Ecosystems Mission Area, Eastern Ecological Science Center

Model selection for the North American Breeding Bird Survey

The North American Breeding Bird Survey (BBS) provides data that can be used in complex, multiscale analyses of population change, while controlling for scale‐specific nuisance factors. Many alternative models can be fit to the data, but most model selection procedures are not appropriate for hierarchical models. Leave‐one‐out cross‐validation (LOOCV), in which relative model fit is...
Authors
William A. Link, John R. Sauer, Daniel K Niven
By
Ecosystems Mission Area, Eastern Ecological Science Center

Variation of annual apparent survival and detection rates with age, year, and individual identity in male Weddell seals (Leptonychotes weddellii) from long-term mark-recapture data

Exploring age- and sex-specific survival rates provides insight regarding population behavior and life-history trait evolution, but many population studies exclude males. Accordingly, our understanding of how age-specific patterns of survival, including actuarial senescence, compare between the sexes remains inadequate. Using 35 years of mark-recapture data for 7,516 male Weddell seals...
Authors
Jamie L. Brusa, Jay J. Rotella, Robert A. Garrott, J. Terrill Paterson, William Link
By
Ecosystems Mission Area, Eastern Ecological Science Center

Consistency counts: Modeling the effects of a change in protocol on Breeding Bird Survey counts

Analysis of North American Breeding Bird Survey (BBS) data requires controls for factors that influence detectability of birds along survey routes. Identifying factors that influence the counting process and incorporating them into analyses is a primary means of limiting bias in estimates of population change. Twedt (2015) implemented an alternative counting protocol on operational and...
Authors
John R. Sauer, William A. Link, David Ziolkowski, Keith L. Pardieck, Daniel J. Twedt
By
Ecosystems Mission Area, Eastern Ecological Science Center

Analysis of population change and movement using robust design removal data

In capture-mark-reencounter studies, Pollock’s robust design combines methods for open populations with methods for closed populations. Open population features of the robust design allow for estimation of rates of death or permanent emigration, and closed population features enhance estimation of population sizes. We describe a similar design, but for use with removal data. Data...
Authors
William A. Link, Sarah J. Converse, Amy A. Yackel Adams, Nathan J. Hostetter
By
Ecosystems Mission Area, Eastern Ecological Science Center

Variation in the vital rates of an Antarctic marine predator: the role of individual heterogeneity

Variation in life‐history traits such as lifespan and lifetime reproductive output is thought to arise, in part, due to among‐individual differences in the underlying probabilities of survival and reproduction. However, the stochastic nature of demographic processes can also generate considerable variation in fitness‐related traits among otherwise‐identical individuals. An improved...
Authors
J. Terrill Paterson, Jay J. Rotella, William A. Link, Robert A. Garrott
By
Ecosystems Mission Area, Eastern Ecological Science Center

On the reliability of N‐mixture models for count data

N‐mixture models describe count data replicated in time and across sites in terms of abundance N and detectability p. They are popular because they allow inference about N while controlling for factors that influence p without the need for marking animals. Using a capture–recapture perspective, we show that the loss of information that results from not marking animals is critical, making...
Authors
Richard J. Barker, Matthew J. Schofield, William A. Link, John R. Sauer
By
Ecosystems Mission Area, Eastern Ecological Science Center

On the robustness of N‐mixture models

N‐mixture models provide an appealing alternative to mark–recapture models, in that they allow for estimation of detection probability and population size from count data, without requiring that individual animals be identified. There is, however, a cost to using the N‐mixture models: inference is very sensitive to the model's assumptions. We consider the effects of three violations of...
Authors
William A. Link, Matthew R. Schofield, Richard J. Barker, John R. Sauer
By
Ecosystems Mission Area, Eastern Ecological Science Center

Model selection for the North American Breeding Bird Survey: A comparison of methods

The North American Breeding Bird Survey (BBS) provides data for >420 bird species at multiple geographic scales over 5 decades. Modern computational methods have facilitated the fitting of complex hierarchical models to these data. It is easy to propose and fit new models, but little attention has been given to model selection. Here, we discuss and illustrate model selection using leave...
Authors
William A. Link, John R. Sauer, Daniel Niven
By
Ecosystems Mission Area, Eastern Ecological Science Center

Identifying Pareto-efficient eradication strategies for invasive populations

Invasive species are a major cause of biodiversity loss and are notoriously expensive and challenging to manage. We developed a decision-analytic framework for evaluating invasive species removal strategies, given objectives of maximizing eradication probability and minimizing costs. The framework uses an existing estimation model for spatially referenced removal data – one of the most...
By
Fort Collins Science Center
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