Effects of site management practices on the avian fauna of the Babe Woodyard State Natural Area, Vermilion Co., Illinois.

S. B. Amundsen

The State of Illinois, Department of Natural Resources (IDNR), has recently acquired and begun development of the Babe Woodyard State Natural Area (BWSNA) in Vermilion Co., Illinois. This 1,044 acre site was once the property of the Peabody Coal Company, and a number of areas within the area were strip-mined during the first half of this century. Agricultural row-crop fields are also located on this site. The management plan for this site includes the development of recreational trails and a primitive campground, the removal of multiflora rose and elimination of fescue grass in old pastures, and the planting of trees in the former row-crop fields within the site. To examine the effects of management practices on the BWSNA bird fauna, avian point counts are being conducted along proposed trail corridors, within fields recently planted in trees and in other areas that will be potentially impacted by development as well as in areas in which no development is planned. The baseline data set produced by this survey will be compared with the results of censuses conducted after development has been completed allowing an assessment of the effects of those changes.

Yellow-headed Blackbird conservation in Illinois

D. A. Enstrom, M. P. Ward, J. Herkert

The ecology and population dynamics of the Yellow-headed Blackbird (Illinois Endangered) are being investigated in northeastern Illinois. The following are being quantified: 1) habitat requirements for the species in Illinois; 2) life history traits of the population, and 3) population dynamics of the population. The genetic relationships among Yellow-headed Blackbird populations from Michigan to the Great Plains are also being investigated. The goal of the project is to produce a viable recovery plan for the species. This study is in its third year.

The function and evolution male and female song in the Orchard Oriole.

D. A. Enstrom, C. Base

This study examines the song culture of the Orchard Oriole, an open country song bird in which females as well as males sing commonly. The study will test hypotheses regarding the function and evolution of female song.

Hormones and mate choice in the Dark-eyed Junco.

D. A. Enstrom, E. D. Ketterson, V. Nolan, Jr.

In 1999 the analysis and synthesis of a long term project investigating the function of testosterone in mate choice in the Dark-eyed Junco was completed.

Mate choice for plumage characters in the Red-winged Blackbird.

D. A. Enstrom, K. Yasukawa

This study generated observational and experimental data on the function of red wing patches in the Red-winged Blackbird.

Site fidelity, return rates, and reproductive success of Grasshopper Sparrows

D.G. Wenny

While habitat preferences of grassland birds are fairly well known, demographic information is not. For this project over 80 grasshopper sparrows were marked with unique combinations of plastic colorbands that allow the identification of individuals from a distance. Territory characteristics, number and success of nesting attempts, mate choice, site fidelity, and adult and natal return rates will all be examined each year on 50 acre plots within Ayers Nature Preserve, Thomson-Fulton Nature Preserve, and Savanna Army Depot.

Abundance and distribution of grassland and forest birds in Northwest Illinois

D.G. Wenny

Breeding bird surveys conducted annually at several sites in the northwestern part of the state to track population changes that may be related to management activities or that can help guide management plans being developed for the sites. Surveys were conducted at Savanna Army Depot, Ayres Sand Prairie Nature Preserve, Thomson-Fulton Nature Preserve, Upper Mississippi Wildlife Refuge (Savanna District), and Mississippi Palisades State Park.

Effects of olfactory cues on post-dispersal seed predation

D.G. Wenny, R.S. Duncan(UF), C.J. Whelan, M. Spritzer(OSU)

Many investigators of seed ecology simulate natural dispersal of seeds by placing seeds into the environment in a controlled manner. In doing so, olfactory cues associated with the investigator may bias results so that ensuing patterns of survivorship do not reflect natural conditions. To test for this effect, an experiment was conducted in which an odor-eliminating product was used to manipulate the level of cue associated with seeds of two common bird-dispersed plant species, Prunus serotina and Cornus drummondii. Results suggest a significant, but relatively weak and short-lived effect of human olfactory cues. Rodents appeared to the main seed predators of these two plant species.

Diets of grassland birds

D.G. Wenny, A Capparella (ISU)

Little is known about the specific diets of grassland birds. Using preserved stomachs from birds collected for other research projects, archival mounts of stomach contents are being prepared using micropaleontology slides. These mounts will allow more detailed identification of seed and insect fragments than is typically done in stomach content studies. Initially identification of insects will be to order and family. Eventually we hope to identify some items to genus or species by comparison with insect reference collections from sites with fairly large numbers of stomachs, and by sending the slides to experts for particular insect groups.

Breeding bird survey of Snakeden Hollow, Knox County

D.G. Wenny

Snakeden Hollow State Fish and Wildlife Area is a reclaimed strip mine area currently managed as a waterfowl refuge. Bird surveys were undertaken to guide management of grassland and woodland birds. Sixty-six species were observed, including 10 grassland and 20 shrubland species. No state or federal endangered or threatened species were observed. The grassland habitat is generally poor but the site has potential for good shrubland habitat.

Bell's vireo (Vireo bellii) reproductive ecology

C. J.Whelan

Bell's vireo is a migratory, shrub-land bird species on the Illinois Watch List, and a sizable population breeds at Midewin National Tallgrass Prairie. Observational study of the species, begun in 1998, continued at Midewin in 1999. Most sites occupied by Bell's vireo in 1998 were also occupied in 1999. In addition, presumably in response to habitat alteration following the cessation of grazing in selected tracts, the Bell's vireo population increased from 1998 to 1999 as new sites were occupied.

Response of woodland birds to removal of woody understory

C. J.Whelan

Many woodland bird species in the Midwest place their nests in the shrub layer, with nests built in either shrubs or saplings. Beginning in 1996, tracts at The Morton Arboretum (Lisle, DuPage County) have been mechanically cleared of virtually all understory woody plants. These tracts had previously been sites of studies of woodland bird reproductive ecology, and in this study repeated censuses are being conducted to document response of the bird community to the clearing. Most species that had occupied the tracts no longer do so.

Linking digestive physiology and consumer-resource theory: application to seasonal diet shifts.

C. J.Whelan, J. S. Brown, K. A. Schmidt, B. B. Steele, M. F. Willson

In this theoretical work, recent advances in digestive physiology were incorporated into the consumer-resource equations, and the resulting models were embeded into three ecological scenarios. In the first scenario, consumers do not deplete their resources; in the second, a fixed population of consumers deplete resources to an equilibrium between consumption and renewal; in the third, resource renewal, depletion, and consumer population sizes equilibrate. Within each scenario, optimal gut physiology is determined under the objective function of maximizing resource harvest.

Foraging under gut constraints: reconciling two schools of thought

C. J. Whelan, J. S. Brown

Many investigators assume that food consumption can be limited by the capacity of the digestive organs (both morphologically and physiologically). In this theoretical work, post-consumption handling of food in the gut is explicitly modeled within a traditional ecological foraging framework (Holling's disc equation), and the consequences of consuming foods that differ in the ratio of richness (energetic or nutritional reward) to bulk (proportion of food item that is resistant or refractory to digestion) are explored. Results thus far indicate that feeding rate is always maximized before gut capacity becomes saturated, suggesting that harvest rate is not constrained by gut capacity. Also, as gut capacity increases, the optimal diet depends upon the ratio of richness to bulk.

Fishes of Illinois: 100 years of change

L. Page, M. Retzer, M. Sabaj

The third survey of Illinois fishes is being conducted with assistance from the IDNR Division of Fisheries. The first survey (published in 1908) documented the presence of 188 native and one nonnative species. The second survey (1979) showed that the number of native species had dropped to 179 and nonnative species had risen to six. Recent data suggest that only 177 native fishes remain, and nonnative species have increased to 15. Some native species are increasing in abundance, but many survive only as small populations in highly fragmented habitats. Most changes are the results of anthropogenic effects such as increased sedimentation. Documenting distributions of Illinois fishes will enhance our ability to protect and restore aquatic communities.

Impacts of silt on stream fishes

S. Herrington, M. Retzer, L. Page

Increased siltation in streams appears to reduce fish production and diversity, although few studies have attempted to quantify the impact. A study has been initiated to examine the relationship between the amount of silt present and fish diversity and biomass in Illinois streams. The impact of silt on fishes will be examined by looking at taxonomic diversity and at species guilds based on habitat, reproductive requirements, and diet. The study is being conducted in tributaries of the Vermilion and Embarras rivers.

Effects of impoundment on small stream fish communities

C. Taylor, J. Knouft

The damming of rivers and streams is a practice that has been occurring in North America for hundreds of years. Besides the obvious physical changes that occur to a flowing body of water, changes to biological communities that inhabit these rivers and streams can also occur after damming. In 1999 we sampled fishes in a small southern Illinois stream to document what changes, if any, have occurred 30 years after the construction of a dam and large reservoir on that stream. Results indicate that substantial changes have occurred in the fish communities that inhabit the stream. Noteworthy changes include the extirpation of at least five species and the introduction and establishment of numerous non-native fishes. This project was completed in 1999 and has been submitted for publication.

Conservation status of the cricket frog in northern Illinois

J. Petzing, C. A. Phillips

The cricket frog (Acris crepitans) was once one of the most abundant frogs in the Midwest. This frog appears to have suffered major population declines in the northern part of its range. The same fate may be occurring in the northern third of Illinois. A statewide survey of 40 randomly chosen historic localities is being conducted to determine the presence and relative abundance of cricket frogs. Surveys were conducted in the spring and fall of 1998 and 1999 with the final survey to be conducted in the spring of 2000. Preliminary results indicate that northeastern Illinois appears to have cricket frogs at fewer historic sites than the rest of the state. This survey will clarify the status of the cricket frog in northern Illinois and provide baseline data for future surveys of the cricket frog throughout Illinois.

The eastern massasauga (Sistrurus catenatus) at Carlyle Lake: activity associated with hibernation egress at South Shore State Park

C.A. Phillips, M. E. Dreslik, B. Jellen

The southern three-quarters of Carlyle Lake has been recognized as one of the last strongholds for the massasauga rattlesnake (Sistrurus catenatus) in Illinois. The purpose of this study was to conduct a systematic survey for massasaugas at South Shore State Park to investigate hibernation habitat characteristics, timing of emergence and dispersal from hibernation sites, and establish baseline population data. Results indicate that massasaugas emerge from hibernation in crayfish burrows in late March and remain in the vicinity of their hibernacula for up to 36 days. Analysis of the hibernation habitat characteristics suggests that during egress, massasaugas actively select locations closer to retreats and shrubs compared to random locations. Close proximity to retreats and shrubs allows snakes to regulate their body temperatures and escape predation. Either of these explanations suggest that shrubs and small trees are an integral part of the overwintering habitat, although the optimal density and spacing of the vegetation remains to be determined.

Field guide to amphibians and reptiles of Illinois

C.A. Phillips, R.A. Brandon, E.O. Moll

A 300 page, hardcover field guide written to aid biologists, naturalists, land managers, law enforcement officials, and students in the identification of the amphibians and reptiles found in Illinois was completed in 1999. The guide contains full-color photographs of all 102 species plus information on habitats, natural history, and distribution. There is also a Web version of the guide with distribution maps that will be updated every few months.

Roosting behavior of the evening bat in Illinois

J.E. Hofmann, J. Kath

In 1999 a radiotracking study of the evening bat, Nycticeius humeralis, was initiated. Relatively little is known about the ecology of this species in Illinois which is at the northern edge of its range. The first phase of the study involves identifying the types of roost sites used by maternity colonies. Two evening bat colonies discovered in Illinois during the 1950's roosted in the attics of buildings and until recently colonies in Indiana had been found only in buildings. In the southern part of their range evening bats commonly roost in hollow trees and also have been found beneath the bark of dead pine trees. The only colony currently known in Indiana roosts in a tree cavity. During 1999 reproductively active females mist-netted at three sites were tracked to dead trees. Once roosts have been identified it will be possible to determine colony size and other aspects of roost selection and use.