Illinois Natural History Survey - University of Illinois

Wetland Bird Conservation in Northeastern Ilinois

Half of the 42 bird species listed as endangered or threatened in Illinois nest exclusively in wetlands. This relatively high proportion of wetland species is largely due to the loss of much of the state's wetland habitat since the early 1800s. Continuing development, which threatens our remaining wetlands and promises further declines for wetland birds, is particularly acute in northeastern Illinois where, in spite of the loss of much of the presettlement wetland acreage, significant populations of wetland birds persist.

A major impediment for wetland bird conservation is the lack of information regarding the population dynamics and habitat requirements for these species. Here we outline three projects that aim to improve our knowledge of wetland-dependent bird species in northeastern Illinois.

A Great Egret, one of the colonial wetland-dependent birds in Illinois being studied by INHS scientists.


I. Abundance and nesting productivity of wetland-dependent birds in northeastern Illinois.

Dr. C.R. Paine of the Max McGraw Wildlife Foundation, in cooperation with the Illinois Department of Natural Resources (IDNR) and the U.S. Fish and Wildlife Service, is conducting a long-term study of wetlands that is designed to provide accurate estimates of the regional abundance and distribution of wetland birds.

Study sites are systematically searched for nests and the fate of all nests recorded. Characteristics (physical and floral) of marshes and nest sites are also recorded. During the 1997 field season a team of 5 researchers working in 10 wetlands located and monitored 450 nests of 13 species. In the coming field season the effort will grow to 11 workers monitoring 90 wetlands.

The goals of this project are to:

1. develop estimates of the dis- tribution and abundance of wetland-dependent birds on a regional scale,

2. assess the health of wetland bird populations in the re- gion,

3. evaluate the effects of habitat characteristics on nest pro- ductivity, and

4. develop conservation priori- ties for wetland birds in the region.


II. The population dynamics of Yellow-headed Blackbirds in northeastern Illinois.

IDNR Natural Heritage biologists have recorded the presence and absence of Yellow-headed Blackbirds at marshes in northeastern Illinois over the past 20 years. These data indicate that Yellow-headed Blackbirds move among sites from year to year, making it difficult to predict the habitat requirements of the population in the long term. In order to better understand the movements of these birds INHS and IDNR scientists are color marking large numbers of individuals.

The goals of this study are to:

1. quantify the reproductive success of Yellow-headed Blackbirds,

2. assess habitat characteristics that favor Yellow-headed Blackbirds, and

3. assess site fidelity and dis- persal in the area. 


III. Use of foraging habitat by herons and egrets in northeastern Illinois.

One of the most difficult problems involving wetland bird conservation in rapidly developing areas is the protection of foraging areas required by colonial waterbirds (e.g., herons and egrets). These species nest in tight aggregations in small areas but forage up to 20 km away in the surrounding wetlands. In order to protect the foraging habitat of these species it is necessary to have accurate estimates of habitat utilization on a large scale. Gathering these data presents significant problems concerning both sampling design and logistics. To overcome the logistical problem volunteers will be used to gather foraging data throughout the region. This summer, trained volunteers from the Bird Conservation Network will collect preliminary data at 12 marshes in Lake and McHenry counties. Information gathered this year will be used to design a long-term monitoring program scheduled to begin in 1999.

A typical wetland in northeastern Illinois that serves as habitat for many species of animals.

David Enstrom, Charles Paine, Mike Ward, and James Herkert, Center for Biodiversity

Illinois Natural History Survey

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Champaign, IL 61820

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