Prairie Research Institute

Illinois Natural History Survey

INHS scientists carry out a range of ornithological research and monitoring activities. Long-range bird monitoring programs generate data that are critical to making informed management and conservation decisions and support Illinois’ outdoor recreation. INHS has over a century of data on bird populations in Illinois and beyond.

Large-scale surveys

INHS scientists conduct many surveys of Illinois’ plant and animal populations, including birds. These surveys help identify long-term population trends and understand potential drivers of these changes, such as habitat loss, invasive species, and environmental stressors.

  • Critical Trends Assessment Program: This program, supported by the Illinois Department of Natural Resources, monitors the biological condition of Illinois’ forests, wetlands, and grasslands. Data from CTAP surveys can be used to assess the occurrence or abundance of individual bird species as well as the number of species found at a particular site.
  • Monitoring Owls and Nightjars: The volunteer-powered Monitoring of Owls and Nightjars (MOON) program conducts annual monitoring to determine population trends and distribution of these nocturnal bird species in Illinois. It also investigates potential causes for the species’ decline, such as decreased habitat availability and food sources, and provides the data needed to implement best management practices to conserve them. This volunteer-based effort is coordinated by ornithologist Tara Beveroth.
  • Spring Bird Count: Each spring, citizen scientists fan out across Illinois to conduct the Spring Bird Count (SBC). These volunteers record all birds that they see and hear on a designated Saturday in May. This annual census began in 1959, and the resulting data can be used to estimate changes in populations of bird species throughout the state.
  • Transportation infrastructure: Ornithological surveys conducted by the INHS Biological Surveys and Assessment Program and Urban Biotic Assessment Program enable the Illinois Department of Transportation and Illinois State Toll Highway System to comply with federal regulations regarding environmental impact, clean water, and endangered species. Data from these surveys support conservation and management efforts.

Read more about INHS environmental assessment work.

Migration ecology

INHS scientists investigate the ecology of birds during migration, including habitat use, stopover duration, movement ecology, and survival of both game and non-game birds during spring and fall migrations.

This includes aerial inventories of Illinois’ waterfowl species along the Illinois and Mississippi rivers that have been conducted by staff at the Forbes Biological Station since 1948. These long-term data are used by state, federal, and private entities to direct waterfowl management, conservation planning, ecological research, and education. The Illinois Department of Natural Resources relies on these inventories to guide the establishment of hunting season dates, zones, and other regulations and to prioritize wetland habitat acquisitions.

Habitat selection and quality

Significant INHS research focuses on understanding the relationships between birds and their habitats, including in wetlands, forests, and agricultural lands. This work informs conservation and management decision making.

Forbes Biological Station scientists assess the quality of wetlands in the Illinois and Mississippi river valleys as stopover sites for waterfowl, monitor waterfowls and waterbirds at the 7,000-acre Emiquon Preserve, while other INHS scientists investigate the effect of forest management on wild turkeys and other forest birds. Other research focuses on the roles of vegetation structure and composition, food resources, landscape context, natural and human-caused disturbances, abiotic factors, and management and restoration actions on habitat use and demographic performance of conservation-priority birds.

For example, scientists from the Forbes Biological Station investigate the impact of prescribed fire in Gulf of Mexico coastal wetlands on three birds of conservation concern. Other scientists are examining habitat use of Eastern Whip-poor-wills during migration and on their wintering grounds in southern Mexico.

Behavior and reproduction

INHS scientists study fundamental questions about bird reproduction and factors that contribute to bird reproductive success and collect data on breeding and nesting habits, incubation, nestling behavior, and post-fledging ecology.

Topics of research interest in the Benson Wildlife Ecology and Conservation Lab, for example, include how birds perceive and respond to nest predation risk, the influence of incubation temperature on development and subsequent consequences for nestlings, how nest composition and structure influence the thermal environment of eggs and nestlings, and the vocal and movement behaviors of birds during the breeding season. Wendy Schelsky and Jeff Hoover conduct long-term monitoring of the Prothonotary Warbler—a migratory, socially monogamous songbird—in southern Illinois swamps and forested wetlands. Their research also focuses on the interactions between Prothonotary Warblers and an Illinois native species of brood parasite, the Brown-headed Cowbird. The Ward Ornithology Lab investigates nest success, adaptive age and timing of fledging, and post-fledging ecology of shrubland birds.

Bird collection

The INHS Bird Collection includes specimens of more than 200 avian species, including rare species such as Sprague’s Pipit, and hundreds of egg sets representing species from throughout the United States. These specimens support research efforts, including the investigation of environmental change over time, such as the presence of chemical pollutants and pathogens, and tracking species distribution and genetic diversity. Data from the bird collection are available through the INHS online portal.

Read more about all INHS biological collections.


Stephen A. Forbes and Alfred O. Gross began North America’s first systematic bird survey in 1906. This survey was repeated by Richard and Jean Graber in 1950 and by a team of INHS ornithologists from 2006 to 2008. This comparison of all three studies was published in 2011 as Illinois Birds – A Century of Change, which is available for purchase in our online shop.

Checklist of Illinois birds