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Christopher "Alex" Hartman

Dr. Alex Hartman is a Wildlife Biologist with the USGS Western Ecological Research Center at the Dixon Field Station. His interests and expertise are in waterbird ecology, wetlands, behavioral ecology, breeding biology, and the effects of contaminants on avian ecology and reproduction.

Education:

  • Ph.D., Ecology, Evolution and Conservation Biology, University of Nevada, Reno, 2008
  • M.Sc., Environmental and Natural Resource Sciences, University of Nevada, Reno, 2003
  • B.Sc., Biological Sciences, University of California, Davis, 1997

 

Professional Experience:

  • Wildlife Biologist, U.S. Geological Survey, Western Ecological Research Center, Dixon Field Station, California (2013-present)
  • Wildlife Biologist, U.S. Geological Survey, Western Ecological Research Center, UC Davis Field Station, California (2011-2013)
  • Shorebird Conservation Biologist, Audubon California, Sacramento, California (2009-2011)
  • Landbird Program Supervisor, San Francisco Bay Bird Observatory, Milpitas, California (2009)
  • Doctoral Research, Program in Ecology, Evolution and Conservation Biology, University of Nevada, Reno (2003-2008)
  • Masters Research, Department of Environmental and Natural Resource Sciences, University of Nevada, Reno (2000-2003)

 

Publications:

2019

Hartman CA, JT Ackerman, MP Herzog, C Strong, and D Trachtenbarg. 2019. Social attraction used to establish Caspian tern nesting colonies in San Francisco Bay. Global Ecology and Conservation 20: e00757.

Hartman CA, JT Ackerman, and MP Herzog. 2019. Mercury exposure and altered parental nesting behavior in a wild songbird. Environmental Science & Technology 53:5396–5405.

Ackerman JT, CA Hartman, and MP Herzog. 2019. Mercury contamination in resident and migrant songbirds and potential effects on body condition. Environmental Pollution 246:797-810.

McDuie F, ML Casazza, CT Overton, MP Herzog, CA Hartman, SH Peterson, CL Feldheim, and JT Ackerman. 2019. GPS tracking data reveals daily spatio-temporal movement patterns of waterfowl. Movement Ecology 7:6.

Peterson SP, JT Ackerman, MP Herzog, CA Hartman, R Croston, CL Feldheim, and ML Casazza. 2019. Sitting ducklings: Timing of hatch, nest departure, and predation risk for dabbling duck broods. Ecology and Evolution 9:5490–5500.

2018

Croston R, CA Hartman, MP Herzog, ML Casazza, and JT Ackerman. 2018. A new approach to automated incubation recess detection using temperature loggers. Condor 120:739–750.

Peterson SH, JT Ackerman, CA Eagles-Smith, MP Herzog, and CA Hartman. 2018. Prey fish returned to Forster’s tern colonies suggest spatial and temporal differences in fish composition and availability. PLoS ONE 13(3):e0193430.

Science and Products

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Clark's Grebe at Thermalito Afterbay, CA

Monitoring Mercury's Risk to Wildlife in California Lakes

USGS scientists sampled grebes in California lakes to compare mercury levels in these predators versus the small fish they prey on—developing a new tool for water quality monitoring.
By
Ecosystems Mission Area, Species Management Research Program, Western Ecological Research Center (WERC)
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Monitoring Mercury's Risk to Wildlife in California Lakes

USGS scientists sampled grebes in California lakes to compare mercury levels in these predators versus the small fish they prey on—developing a new tool for water quality monitoring.
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Nest Attendance, Incubation Constancy, and Onset of Incubation in Dabbling Ducks

This dataset includes daily nest attendance (proportion of time females spent at the nest), incubation constancy (proportion of time females maintained their nests at nest-specific incubation temperatures), nest temperature variation, and the duration of individual incubation bouts for three species of dabbling ducks (mallard, gadwall, and cinnamon teal) nesting in Suisun Marsh, California during
By
Western Ecological Research Center (WERC)

How Mallard and Gadwall Hens Nesting in Grizzly Island Wildlife Area Respond when Flushed (2015 - 2018)

This dataset describes responses to flushes by surveyors and predators for mallard and gadwall hens nesting on the Grizzly Island Wildlife Area, Suisun Marsh, California in 2015 through 2018. It includes the start time and duration of recesses, as well as the cause of recess initiation and responses of hens to various trapping activities at the nest site. These data support the following publ
By
Western Ecological Research Center (WERC)

Breeding Waterbird Populations in South San Francisco Bay 2005-2019

The dataset includes three separate excel spreadsheets which provides waterbird (and predator) observations within individual survey units during the May 2019 breeding waterbird survey of south San Francisco Bay (2019WaterbirdSurveyFullData.xlsx), the total number of American avocets, black-necked stilts, and Forster's terns within each pond unit surveyed during the May 2019 survey (2019WaterbirdS
By
Western Ecological Research Center (WERC)

Incubation Constancy, Number of Incubation Recesses, Recess Duration and Mercury Concentrations for Tree Swallows at the Cosumnes River Preserve 2014

These metadata provide data used to examine tree swallow incubation behavior in relation to egg mercury concentration and maternal blood mercury concentration. These data were collected from tree swallows nesting in artificial wooden nest boxes at the Cosumnes River Preserved in California's Central Valley in 2014. Included are two datasets. One dataset provides daily incubation constancy (the pro
By
Western Ecological Research Center (WERC)
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Monitoring nesting waterbirds for the South Bay Salt Pond Restoration Project—2022 breeding season

The San Francisco Bay supports thousands of breeding waterbirds annually and hosts large populations of American avocets (Recurvirostra americana), black-necked stilts (Himantopus mexicanus), and Forster’s terns (Sterna forsteri). These three species have relied largely on former commercial salt ponds in South San Francisco Bay, which provide wetland foraging habitat and island nesting habitat. Th
Authors
Joshua T. Ackerman, C. Alex Hartman, Mark P. Herzog
By
Ecosystems Mission Area, Western Ecological Research Center (WERC)

Nest attendance, incubation constancy, and onset of incubation in dabbling ducks

In birds, parents must provide their eggs with a safe thermal environment suitable for embryonic development. Species with uniparental incubation must balance time spent incubating eggs with time spent away from the nest to satisfy self-maintenance needs. Patterns of nest attendance, therefore, influence embryonic development and the time it takes for eggs to hatch. We studied nest attendance (tim
Authors
C. Alex Hartman, Josh T. Ackerman, Sarah H. Peterson, Brady Lynn Fettig, Michael L. Casazza, Mark P. Herzog
By
Ecosystems Mission Area, Western Ecological Research Center (WERC)

Habitat use by breeding waterbirds in relation to tidal marsh restoration in the San Francisco Bay estuary

The South Bay Salt Pond Restoration Project aims to restore many former salt production ponds, now managed for wildlife and water quality, to tidal marsh. However, because managed ponds support large densities of breeding waterbirds, reduction of pond habitat may influence breeding waterbird distribution and abundance. We investigated habitat use associated with breeding, feeding, and roosting beh
Authors
Carley Rose Schacter, C. Alex Hartman, Mark P. Herzog, Sarah H. Peterson, Max L. Tarjan, Yewei Wang, Cheryl Strong, Rachel Tertes, Neil Warnock, Josh T. Ackerman
By
Ecosystems Mission Area, Western Ecological Research Center (WERC)

Dabbling duck eggs hatch after nest abandonment in the wild

In most birds, parental incubation of eggs is necessary for embryo development and survival. Using a combination of weekly nest visits, temperature dataloggers, infrared video cameras, and GPS tracking of hens, we documented several instances of duck eggs hatching after being abandoned by the incubating female. Of 2826 Mallard (Anas platyrhynchos) and Gadwall (Mareca strepera) nests monitored 2015
Authors
Carley Rose Schacter, Brady Lynn Fettig, Sarah H. Peterson, C. Alex Hartman, Mark P. Herzog, Michael L. Casazza, Josh T. Ackerman
By
Ecosystems Mission Area, Western Ecological Research Center (WERC)

Predator movements in relation to habitat features reveal vulnerability of duck nests to predation

Nest predation is the main cause of nest failure for ducks. Understanding how habitat features influence predator movements may facilitate management of upland and wetland breeding habitats that reduces predator encounter rates with duck nests and increases nest survival rates. For 1618 duck nests, nest survival increased with distance to phragmites (Phragmites australis), shrubs, telephone poles,
Authors
Sarah H. Peterson, Josh T. Ackerman, Meghan P Keating, Carley Rose Schacter, C. Alex Hartman, Michael L. Casazza, Mark P. Herzog
By
Ecosystems Mission Area, Western Ecological Research Center (WERC)

Breeding waterbird populations have declined in south San Francisco Bay: An assessment over two decades

In south San Francisco Bay, former salt ponds now managed as wildlife habitat support large populations of breeding waterbirds. In 2006, the South Bay Salt Pond Restoration Project began the process of converting 50% to 90% of these managed pond habitats into tidal marsh. We compared American Avocet (Recurvirostra americana) and Black-necked Stilt (Himantopus mexicanus) abundance in south San Fran
Authors
C. Alex Hartman, Josh T. Ackerman, Carley Rose Schacter, Mark P. Herzog, Max Tarjan, Yiwei Wang, Cheryl Strong, Rachel Tertes, Nils Warnock
By
Ecosystems Mission Area, Western Ecological Research Center (WERC)

Wetland availability and salinity concentrations for breeding waterfowl in Suisun Marsh, California

Availability of wetlands with low salinities during the breeding season can influence waterfowl reproductive success and population recruitment. Salinities as low as 2 ppt (3.6 mScm–1) can impair duckling growth and influence behavior, with mortality occurring above 9 ppt (14.8 mScm–1). We used satellite imagery to quantify the amount of available water, and sampled surface water salinity at Grizz
Authors
Carley Rose Schacter, Sarah H. Peterson, Mark P. Herzog, C. Alex Hartman, Michael L. Casazza, Josh T. Ackerman
By
Ecosystems Mission Area, Western Ecological Research Center (WERC)

Nocturnal incubation recess and flushing behavior by duck hens

Incubating birds must balance the needs of their developing embryos with their own physiological needs, and many birds accomplish this by taking periodic breaks from incubation. Mallard (Anas platyrhynchos) and gadwall (Mareca strepera) hens typically take incubation recesses in the early morning and late afternoon, but recesses can also take place at night. We examined nocturnal incubation recess
Authors
Rebecca Croston, Sarah H. Peterson, C. Alex Hartman, Mark P. Herzog, Cliff L. Feldheim, Michael L. Casazza, Josh T. Ackerman
By
Ecosystems Mission Area, Western Ecological Research Center (WERC)

Egg morphometrics and egg shape coefficients for White-faced Ibis (Plegadis chihi)

Egg size is a useful metric for maternal investment, offspring quality, and contaminant studies. Yet these values and the egg shape coefficients required to estimate egg size are not available for many species, including White-faced-Ibis (Plegadis chihi). We provide egg morphometrics derived from 319 White-faced Ibis eggs sampled at Bear River Migratory Bird Refuge, Great Salt Lake, Utah, from 201
Authors
Mark P. Herzog, Josh T. Ackerman, C. Alex Hartman
By
Ecosystems Mission Area, Western Ecological Research Center (WERC)

Interrupted incubation: How dabbling ducks respond when flushed from the nest

Nesting birds must provide a thermal environment sufficient for egg development while also meeting self‐maintenance needs. Many birds, particularly those with uniparental incubation, achieve this balance through periodic incubation recesses, during which foraging and other self‐maintenance activities can occur. However, incubating birds may experience disturbances such as predator or human activit
Authors
Rebecca Croston, C. Alex Hartman, Mark P. Herzog, Sarah H. Peterson, Jeffrey Kohl, Cory T. Overton, Cliff L. Feldheim, Michael L. Casazza, Josh T. Ackerman
By
Ecosystems Mission Area, Western Ecological Research Center (WERC)

Mercury exposure in mammalian mesopredators inhabiting a brackish marsh

Bioaccumulation of environmental contaminants in mammalian predators can serve as an indicator of ecosystem health. We examined mercury concentrations of raccoons (Procyon lotor; n = 37 individuals) and striped skunks (Mephitis mephitis; n = 87 individuals) in Suisun Marsh, California, a large brackish marsh that is characterized by contiguous tracts of tidal marsh and seasonally impounded wetland
Authors
Sarah H. Peterson, Josh T. Ackerman, C. Alex Hartman, Michael L. Casazza, Cliff L. Feldheim, Mark P. Herzog
By
Ecosystems Mission Area, Western Ecological Research Center (WERC)

Establishing Forster’s Tern (Sterna forsteri) nesting sites at pond A16 using social attraction for the South Bay Salt Pond restoration project

Forster’s terns (Sterna forsteri), historically one of the most numerous colonial-breeding waterbirds in South San Francisco Bay, California, have experienced recent decreases in the number of nesting colonies and overall breeding population size. The South Bay Salt Pond Restoration Project aims to restore 50–90 percent of former salt evaporation ponds to tidal marsh habitat in South San Francisco
Authors
C. Alex Hartman, Josh T. Ackerman, Mark P. Herzog, Yiwei Wang, Cheryl Strong
By
Ecosystems Mission Area, Western Ecological Research Center (WERC)
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Research Spotlight: Mercury Exposure in Wild Songbirds Associated with Disrupted Parental Care at the Nest

In a study published in the journal Environmental Science and Technology, U.S. Geological Survey biologists report that methylmercury concentrations...

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USGS Scientists Find Success in New "Real Estate" for Waterbirds

There’s hot new real estate for wildlife in south San Francisco Bay, and a report from USGS biologists shows that the waterbirds are flocking in.

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