Pacific Island Bird Survey Design and Data Analysis
Abundance data are collected for bird populations throughout the Pacific Islands by numerous federal, state, university, and non-profit organizations. In order to ensure data are standardized and available to researchers throughout the region, interagency bird databases have been created and continue to be used. These databases contain more than a million compiled, proofed, and standardized records collected over the past 40 years.
Overview:
Abundance survey data represent a valuable informational resource that was not accessible in the past. Analysis of historical data is largely complete, but analysis and reports of new survey data continue to provide important information for managers. These reports deliver revised distribution maps and population estimates (for native and non-native birds and invasive species), examine population trends, help test hypotheses for the causes of decline, develop habitat suitability models, and support resource managers in conservation planning and decision-making. The database and results are available to scientists and natural resource managers throughout the Hawaiian Islands.
Project Locations
Pacific Island National Parks - Inventory & Monitoring: The U.S. National Park Service (NPS) implemented a strategy to institutionalize natural resource inventory and monitoring to ensure that the approximately 270 park units possess the information needed for effective, science-based decision-making and resource protection. The strategy supports (1) basic natural resources inventories, (2) evaluation of experimental monitoring designs and strategies, and (3) operational monitoring of critical parameters in all natural resource parks. More than 10 Pacific parks design and test prototype protocols to lead as examples of successful monitoring program development.
USGS researchers work with NPS partners to evaluate monitoring protocols, report on the status of endangered birds and the invasive species that affect them, and provide quality data that support natural resource inventories in the Pacific parks.
Hawaii U.S. Fish & Wildlife Refuges: Since 1999, the Hawaii Forest Bird Interagency Database Project (HFBIDP) has compiled, reviewed, and standardized records from over 800 forest bird surveys conducted throughout Hawaii by 22 agencies and organizations. The database and results are available to scientists and natural resource managers to elucidate trends in distribution and density of species of concern (both endangered and invasive species), test hypotheses for the causes of population change, examine the results of management actions, and guide future survey effort, conservation planning, and decision-making. USGS researchers add to this decades-spanning database and report on the status of endangered and non-native bird species in the refuges managed by the Hawaii U.S. Fish and Wildlife Service.
Nihoa: The Nihoa millerbird (Acrocephalus familiaris kingi) and Nihoa finch (Telespiza ultima) are endangered passerine birds endemic to the island of Nihoa, part of the Hawaiian Islands National Wildlife Refuge (HINWR) in the Papahānaumokuākea Marine National Monument. The refuge extends about 1300 km along the northwestern chain of Hawaiian Islands and provides habitat for over 30 species and 14 million breeding seabirds, wintering shorebirds, and endangered endemic songbirds and waterfowl. At about 1 square km in size, Nihoa is home to the two endemic land birds, 72 terrestrial arthropods, an endangered fan palm and shrub, and other native plants.
Reducing risks to the endemic Nihoa millerbird and Nihoa finch requires understanding their population trends to project anticipated trajectories, evaluate the potential impact of translocation, and prioritize management actions. The former survey protocol produced a wide range of annual population estimates for both species. For example, between 1967 and 2009, millerbird point estimates ranged from 30 to 814. This very high variability made determining the actual population size and assessing management actions problematic. It also required long periods of surveys before statistically significant trends could be determined.
USGS biologists evaluated the Nihoa passerine survey methods to improve the accuracy of density and population estimates for the Nihoa millerbird and Nihoa finch. A final report and journal manuscript are available.
Mauna Kea, Island of Hawai‘i: The palila (Loxioides bailleui) is an endangered species of Hawaiian honeycreeper which exists only in subalpine forests dominated by māmane (Sophora chrysophylla) and naio (Myoporum sandwichense) on Mauna Kea volcano. The diet of this finch-billed bird is unusually restricted; immature seeds, flowers, and insects found on māmane trees are critical to its existence. Māmane is also the preferred nesting substrate of the palila. Federal court orders have resulted in efforts to reduce populations of introduced feral sheep and mouflon sheep within Palila Critical Habitat, because they eliminate most māmane regeneration and modify forest structure. U.S. Fish and Wildlife Service specified mitigation of the effects of realigning Saddle Road (Highway 200) through Palila Critical Habitat to include restoration research to guide the conservation of palila within their core range and to develop techniques for reestablishing a population within a portion of its former range. In addition, cattle grazing leases were withdrawn to allow forest restoration in areas formerly occupied by palila. The U.S. Army has also agreed to manage former palila habitat within Pōhakuloa Training Area for palila restoration. The concentration of palila in dry, highly flammable subalpine forest increases the threat of extinction due to many factors. Of greatest concern is the reduction of habitat carrying capacity resulting from long-term browsing by introduced sheep and the likelihood that drought severity and frequency is increasing due to climate change. Managers need both comprehensive ecological information for developing management strategies and practical information and techniques to effectively restore populations and habitats.
Guam & Commonwealth of the Northern Mariana Islands:
The birds of the Mariana Islands, an archipelago of 15 islands in the western Pacific, are threatened by habitat loss or conversion and the spread of non-native species, particularly a devastating predator, the brown treesnake (Boiga irregularis). The accidental introduction of the brown treesnake to Guam after World War II resulted in the loss of 13 of 22 native birds on the island. However, the Mariana Islands remains an Endemic Bird Area of the Pacific as identified by BirdLife International and is a biodiversity hotspot within Micronesia. The native land bird fauna of the Mariana Islands is currently composed of 19 species, of which 16 have highly restricted ranges and 10 are endemic to the archipelago. Remaining native avifauna now largely persist on the islands north of Guam — Rota, Aguiguan, Tinian Island, and Saipan Island, which are part of the Commonwealth of the Northern Mariana Islands (CNMI).
Although there have been reports of the brown treesnake from some islands of the CNMI, particularly from the most populous island, Saipan Island, surveys have not yet demonstrated the existence of a population there. Nevertheless, without intensive prevention efforts, the snake could establish itself in the CNMI. Other invasive species also pose serious threats to the CNMI avifauna through predation and habitat alteration. Research can help identify how competition and disease could be affecting native birds.
The USGS provides technical assistance to the U.S. Fish and Wildlife Service, CNMI Division of Fish & Wildlife, and Department of War by developing methods for conducting effective bird survey and monitoring programs, analyzing and interpreting data to determine population abundance and trends, and developing new tools to understand difficult-to-monitor populations. See Publications tab to learn more about this USGS research.
Abundance data are collected for bird populations throughout the Pacific Islands by numerous federal, state, university, and non-profit organizations. In order to ensure data are standardized and available to researchers throughout the region, interagency bird databases have been created and continue to be used. These databases contain more than a million compiled, proofed, and standardized records collected over the past 40 years.
Overview:
Abundance survey data represent a valuable informational resource that was not accessible in the past. Analysis of historical data is largely complete, but analysis and reports of new survey data continue to provide important information for managers. These reports deliver revised distribution maps and population estimates (for native and non-native birds and invasive species), examine population trends, help test hypotheses for the causes of decline, develop habitat suitability models, and support resource managers in conservation planning and decision-making. The database and results are available to scientists and natural resource managers throughout the Hawaiian Islands.
Project Locations
Pacific Island National Parks - Inventory & Monitoring: The U.S. National Park Service (NPS) implemented a strategy to institutionalize natural resource inventory and monitoring to ensure that the approximately 270 park units possess the information needed for effective, science-based decision-making and resource protection. The strategy supports (1) basic natural resources inventories, (2) evaluation of experimental monitoring designs and strategies, and (3) operational monitoring of critical parameters in all natural resource parks. More than 10 Pacific parks design and test prototype protocols to lead as examples of successful monitoring program development.
USGS researchers work with NPS partners to evaluate monitoring protocols, report on the status of endangered birds and the invasive species that affect them, and provide quality data that support natural resource inventories in the Pacific parks.
Hawaii U.S. Fish & Wildlife Refuges: Since 1999, the Hawaii Forest Bird Interagency Database Project (HFBIDP) has compiled, reviewed, and standardized records from over 800 forest bird surveys conducted throughout Hawaii by 22 agencies and organizations. The database and results are available to scientists and natural resource managers to elucidate trends in distribution and density of species of concern (both endangered and invasive species), test hypotheses for the causes of population change, examine the results of management actions, and guide future survey effort, conservation planning, and decision-making. USGS researchers add to this decades-spanning database and report on the status of endangered and non-native bird species in the refuges managed by the Hawaii U.S. Fish and Wildlife Service.
Nihoa: The Nihoa millerbird (Acrocephalus familiaris kingi) and Nihoa finch (Telespiza ultima) are endangered passerine birds endemic to the island of Nihoa, part of the Hawaiian Islands National Wildlife Refuge (HINWR) in the Papahānaumokuākea Marine National Monument. The refuge extends about 1300 km along the northwestern chain of Hawaiian Islands and provides habitat for over 30 species and 14 million breeding seabirds, wintering shorebirds, and endangered endemic songbirds and waterfowl. At about 1 square km in size, Nihoa is home to the two endemic land birds, 72 terrestrial arthropods, an endangered fan palm and shrub, and other native plants.
Reducing risks to the endemic Nihoa millerbird and Nihoa finch requires understanding their population trends to project anticipated trajectories, evaluate the potential impact of translocation, and prioritize management actions. The former survey protocol produced a wide range of annual population estimates for both species. For example, between 1967 and 2009, millerbird point estimates ranged from 30 to 814. This very high variability made determining the actual population size and assessing management actions problematic. It also required long periods of surveys before statistically significant trends could be determined.
USGS biologists evaluated the Nihoa passerine survey methods to improve the accuracy of density and population estimates for the Nihoa millerbird and Nihoa finch. A final report and journal manuscript are available.
Mauna Kea, Island of Hawai‘i: The palila (Loxioides bailleui) is an endangered species of Hawaiian honeycreeper which exists only in subalpine forests dominated by māmane (Sophora chrysophylla) and naio (Myoporum sandwichense) on Mauna Kea volcano. The diet of this finch-billed bird is unusually restricted; immature seeds, flowers, and insects found on māmane trees are critical to its existence. Māmane is also the preferred nesting substrate of the palila. Federal court orders have resulted in efforts to reduce populations of introduced feral sheep and mouflon sheep within Palila Critical Habitat, because they eliminate most māmane regeneration and modify forest structure. U.S. Fish and Wildlife Service specified mitigation of the effects of realigning Saddle Road (Highway 200) through Palila Critical Habitat to include restoration research to guide the conservation of palila within their core range and to develop techniques for reestablishing a population within a portion of its former range. In addition, cattle grazing leases were withdrawn to allow forest restoration in areas formerly occupied by palila. The U.S. Army has also agreed to manage former palila habitat within Pōhakuloa Training Area for palila restoration. The concentration of palila in dry, highly flammable subalpine forest increases the threat of extinction due to many factors. Of greatest concern is the reduction of habitat carrying capacity resulting from long-term browsing by introduced sheep and the likelihood that drought severity and frequency is increasing due to climate change. Managers need both comprehensive ecological information for developing management strategies and practical information and techniques to effectively restore populations and habitats.
Guam & Commonwealth of the Northern Mariana Islands:
The birds of the Mariana Islands, an archipelago of 15 islands in the western Pacific, are threatened by habitat loss or conversion and the spread of non-native species, particularly a devastating predator, the brown treesnake (Boiga irregularis). The accidental introduction of the brown treesnake to Guam after World War II resulted in the loss of 13 of 22 native birds on the island. However, the Mariana Islands remains an Endemic Bird Area of the Pacific as identified by BirdLife International and is a biodiversity hotspot within Micronesia. The native land bird fauna of the Mariana Islands is currently composed of 19 species, of which 16 have highly restricted ranges and 10 are endemic to the archipelago. Remaining native avifauna now largely persist on the islands north of Guam — Rota, Aguiguan, Tinian Island, and Saipan Island, which are part of the Commonwealth of the Northern Mariana Islands (CNMI).
Although there have been reports of the brown treesnake from some islands of the CNMI, particularly from the most populous island, Saipan Island, surveys have not yet demonstrated the existence of a population there. Nevertheless, without intensive prevention efforts, the snake could establish itself in the CNMI. Other invasive species also pose serious threats to the CNMI avifauna through predation and habitat alteration. Research can help identify how competition and disease could be affecting native birds.
The USGS provides technical assistance to the U.S. Fish and Wildlife Service, CNMI Division of Fish & Wildlife, and Department of War by developing methods for conducting effective bird survey and monitoring programs, analyzing and interpreting data to determine population abundance and trends, and developing new tools to understand difficult-to-monitor populations. See Publications tab to learn more about this USGS research.