Lark Sparrow genetics and ecology
Jeremy Ross (Bowling Green State University)

A continent-wide study of Lark Sparrow (Chondestes grammacus).

Restoration of Sand Prairie in Illinois: Seed Banks and Existing Vegetation
Molly McNicoll (University of Illinois at Champaign-Urbana)

Our objectives for this research are to compare the vegetation of native sand prairie to the present vegetation of former sand prairie that was protected from external impacts and vegetation for 80 years, and former sand prairie with a long grazing history. The proposed research will be conducted on successional and former sand prairie at the Lost Mound Unit, including areas dominated by little bluestem (Scizachyrium scoparium) and exotic annual grasses (Bromus spp.). Sample plots will also be located on bare ground sites that were created by the removal of storage platforms in December 2004. These bare ground sites will provide a view of sand prairie succession from the seed bank and immediately adjacent seed sources.

Reproductive ecology of fragile prickly pear (Opuntia fragilis)
Barbara Anderson and Eric Ribbens (Western Illinois University)

Nest site selection of turtles
F. Janzen (Iowa State University)

Site fidelity and return rates of grassland birds.
Dan Wenny

The upland portion of Lost Mound Unit has been designated a Nationally Important Bird Area. It provides critical habitat for many grassland birds, including nine species of high concern in Region 3. The extent to which grassland birds return to the same site to breed in successive years, however, is poorly understood. This project would be an expansion of work funded by IDNR over the past two years. In that work, over 300 grassland birds were banded at 10ha sites at three sand prairies: Lost Mound, Thomson, and Ayers. Approximately 30% of adult birds banded in 2001 retuned in 2002, but the fate of the remaining 70% of birds is unclear. Previous studies tend to assume most of these “missing” birds die rather than disperse to other sites. In this project we propose to continue banding in the 10ha study sites, and more importantly, search the surrounding areas for returning banded birds. Thus we will be able to estimate the number of birds that disperse to new sites rather than return to the same breeding site. This type of work has not been conducted with any grassland birds. The results will therefore be useful for other grasslands in the region.

Photo of banded Grasshopper sparrow

Grassland bird habitat use in Northwest Illinois: The roles of vegetation structure, plant community composition, and landscape factors
Dan Wenny, Amy Symstad (INHS now USGS), and Jim Rachuy (Prairie Enthusiasts)

The regional and national population declines of grassland birds have attracted much attention. The primary cause of these declines is habitat loss mainly as a result of agricultural intensification. The Conservation Reserve Program (CRP), intended to take marginal land out of crop production, and a growing interest in prairie restoration has led to an expansion of grassland habitats in some areas. This study was designed to examine grassland bird use of various grassland habitats in northwestern Illinois in order to develop management recommendations to benefit grassland birds.

Most previous studies indicate that vegetation structure is far more important than species composition of the plant community for grassland birds (Herkert et al. 1993). This idea is certainly true when different plant species have the same growth form or when different management practices produce different vegetation structure from the same plant species. On the other hand, a common expectation in ecology is that diversity begets diversity. In other words, areas with differing plant species composition should also have different bird communities and, possibly, areas with greater plant diversity will support a greater diversity of birds. While several studies have examined grassland bird communities in native and non-native grasslands (Sutter and Brigham 1998, Davis and Duncan 1999, Washburn et al. 2000, Ludwig et al. 2001), none have examined the influence of plant species diversity on grassland bird diversity in detail.

The underlying expectation is that because grassland birds in central North America existed in prairie vegetation for at least 8,000 years, prairies, and by analogy prairie restorations, should provide optimal habitat for them. On the other hand, non-native cool season grasses have dominated grassland habitats east of the Mississippi river for the past 300 years after European settlers replaced forest with pastures, hayfields, and other agricultural lands. In this study we examined the relationship between grassland bird diversity and abundance and plant diversity and vegetation structure across a variety of grasslands in Jo Daviess and Carroll counties, Illinois. Because the structure of the landscape is also known to affect grassland bird habitat selection (Helzer and Jelinski 1999, Winter and Faaborg 1999, Haire et al. 2000, Soderstrom and Part 2000, Coppedge et al. 2001), we also incorporated landscape parameters that may confound effects of diversity and structure.

Prairie bird response to cessation of grazing.
Dan Wenny, Ed Anderson (IDNR), Randy Nyboer, and Jim Herkert (TNC)

Winter diet of long-eared owls at Lost Mound.
Dan Wenny and Natural Area Guardians

Long-eared owls (Asio otus) formerly nested in northern Illinois. They were removed from the Illinois Endangered Species list because the breeding population has been extirpated. Now long-eared owls occur in Illinois only in the winter, primarily in the northern part of the state. Protecting and maintaining significant winter roost areas may facilitate the establishment of a breeding population as occurred during the recovery of bald eagles (Haliaeetus leucocephalus) in the midwest. We have located a roost of 30-40 birds at the Lost Mound Unit of the Upper Mississippi River National Wildlife Refuge. This group of birds was the largest report for the species during the Great Backyard Bird count in Feb. 2004 (so large in fact that staff from Cornell questioned the numbers sent in!). Although long-eared owls had been reported from this area in previous years, it appears that the number of owls at Lost Mound in winter has increased since grazing by cattle ceased in 1999. A better understanding of the winter habits of these owls may help with recovery efforts.

Objectives:
1. Determine relative abundance of prey species in Long-eared owl diet from the winters of 2002-03 and 2003-04.

2. Estimate the number of each rodent species eaten over the course of the winter.

3. Measure selected bones to estimate age classes of rodents eaten by the owls (Lyman et al. 2001).

4. Compare relative abundance of rodents in owl diet with past studies of small mammal abundance (Anderson et al. 1994, Hofmann et al. 2000).

5. Compare the results from this study with other studies on owl diets in the Midwest (Cahn and Kemp 1930, Errington 1932, Voight and Glenn-Lewin 1978).

6. Involve volunteers with field station research.

Photo of owl pellets

Seed dispersal by birds and woody encroachment of sand prairie.
Dan Wenny, Joan Harmet (Natural Area Guardians), and Randy Nyboer.

We investigated patterns of seed dispersal by birds under different tree species at Lost Mound in JoDaviess County, Illinois. The site is a 4,000 acre sand prairie that has been grazed by cattle for at least 40 years but has not been burned for many years. Control of woody vegetation is a main management issue. Seeds were collected in 75cm X 75cm seed traps made of aluminum window screen supported on a PVC frame 75 cm above the ground. In July 2002 traps were placed under black cherry (Prunus serotina), honey locust (Gledista tricanthos), red cedar (Juniperus virginiana), and dead trees. Traps were placed under 12 isolated individuals of each species. These treatments represent three of the most common tree species in the prairie and dead trees represent the result of girdling trees (a typical management strategy for controlling woody species in prairies). Seeds were collected monthly, stored in vials and later identified to species. Seed rain varied widely among traps, among treatments, and among months. The number and diversity of seeds was higher under dead trees than live trees and higher under cherry than locust. In March 2003 we girdled the locust trees and we added 12 traps each under box elder (Acer negundo) and black oak (Quercus velutina). As expected, seed rain increased up to four times under dead locusts compared to the live locusts the year before. Seed rain under box elder and oak was lower than under dead trees and species with fleshy fruits that attract birds (cherry, cedar). These results suggest that girdling trees may actually increase woody encroachment under some circumstances. Given a choice and assuming limited time and workforce, site managers should consider removing woody species with fleshy fruits before other species.

Historic endangered and threatened plant species element occurrence updates for Illinois Department of Natural Resources Administrative Region 1.
Randy Nyboer, A. Mankowski, and Dan Wenny

The Illinois Natural Heritage Biological Conservation Database (BCD) documents 212 endangered and threatened plant element occurrences that are 8 years or older (at 175 locations in 19 counties representing 81 listed species) for Illinois Department of Natural Resources (IDNR) Region 1. It is desirable for these records to be re-surveyed and updated to provide current listed species status and distribution information that is utilized by: the IDNR for the Endangered Species Consultation Process, the Comprehensive Environmental Review Process, Natural Area protection and management, and maintenance of the BCD; the Illinois Endangered Species Protection Board for Species Listing evaluations and Recovery planning; and, the Illinois Nature Preserves Commission for evaluating and engaging in Natural Area management, preservation and protection. With the current Natural Heritage vacancies in Region 1 (three vacancies out of seven positions = <60% staffed) and expected future budget shortfalls, there is a need to contract this work to an outside source.

This proposal is to conduct field surveillance of up to approximately 212 element occurrences over the course of two years. The FY04 work will focus on counties with the highest concentrations of historic plant EOs - Winnebago (54 occurrences), Ogle (44 occurrences), and JoDaviess (39 occurrences) Counties, and adjacent county EOs will be included when time and travel allows. The 2005 work will focus on the remaining EOs (up to 75 occurrences across 16 counties) and additional work on locating selected occurrences searched for but not found in the previous year. Work may also include library and herbarium searches and may require multi-seasonal field checks. GPS coordinates will be recorded for all element occurrences successfully relocated. This proposal acknowledges that due to phenology, annual and seasonal climatic variability, and other potentially site-specific conditions, the confirmation of some EOs may not be possible during this two-year study. A first year report will be completed by December 2004 and will include survey data, summary, progress report, and pertinent maps including copies of all EORs. A final report will be completed by December 2005 and will include the same information for the 2005 work (2004 results should be included in the summary). Locations of any threatened and endangered species, as well as documentation of absences (or “not found”) for historic locations, will be recorded and reported to the Natural Heritage Biological Conservation Database via Element Occurrence Records.

Ecology and conservation of Swainson’s Hawk in Illinois.
Dan Wenny, D. Kirk (IDNR), Dave Enstrom (INHS), T. Coleman (UIUC), Ken Paige (UIUC)

A small population of Swainson’s Hawk persists in northeastern Illinois. This population is isolated from the larger western populations by about 500 miles. We propose a basic study to determine habitat requirements, nesting success, and return rates of the Illinois birds. In addition, we will compare the genetic relationship of the Illinois population with two western populations to examine the distinctness of the Illinois population. The results of this study will be used to assess the feasibility of maintaining the population in Illinois and, if appropriate, to develop management guidelines to do so.

Swainson’s Hawk occurs in Illinois only in Kane and possibly McHenry counties. A small population of this species has persisted since presettlement times. Although Swainson’s Hawk is fairly common in the western US, apparently it has always been rare in Illinois (Ridgway 1889, Cory 1909, Bohlen 1989). Swainson’s Hawk is listed as state-endangered in Illinois but no recent studies have been conducted and virtually nothing is known about this population. The Illinois population likely has been isolated from the western populations for over 150 years and information about the ecology of western populations may not apply to the Illinois population.

In the west, Swainson’s hawk is mainly a grassland species (England et al. 1997). In Illinois, this species nests in woodlands imbedded in an agricultural matrix. The rapid changes in land use in this area of Illinois, in particular the decline in agricultural land and projected increase in residential areas (CRBC 1999), may jeopardize the future survival of the hawk. Because Swainson’s Hawks have large home ranges (approximately 20 km2; England et al. 1997) measures taken to protect this species will benefit many other species as well. Although a predatory species, Swainson’s Hawk eat mostly small rodents and large insects (esp. grasshoppers) and are not a threat to livestock or pets. Thus, the hawks and humans can coexist if habitat needs are taken into account (e.g., Brawn and Stotz 2001).

The goals of this project are to locate and monitor all Swainson’s Hawk breeding sites in northeastern Illinois. We seek basic demographic data and patterns of habitat use to estimate the viability of the population and management needs over the next several decades. An additional goal is to determine if the Illinois population is genetically distinct from the western populations. The extent to which the Illinois birds are reproductively isolated from the western populations will help estimate population viability. The information from this project will help prioritize the needs and goals of conservation efforts for Swainson’s Hawk in Illinois.

Photo of a Swainson's Hawk nestling

Woody plant invasion of grasslands: interaction between seed dispersal and microhabitat characteristics.
Dan Wenny, Christopher J. Whelan (INHS-Midwein), and Norbert J. Cordeiro (Field Museum)

Invasion of grasslands by woody plant species is of global concern. Plant invasion consists of linked processes, beginning with seed arrival and survival, and progressing through seedling germination and establishment, local spread and population growth, to local dominance. Surprisingly, seed arrival, the initial phase of invasion, is little investigated and poorly understood.

Here we propose to investigate seed arrival, survival, and invasion of native and non-native woody plant species into two federally-protected grasslands. Our study sites, the Lost Mound Unit of the Upper Mississippi River National Wildlife Refuge (US Fish & Wildlife Service and the Illinois DNR) and Midewin National Tallgrass Prairie (US Forest Service and IDNR), are both designated prairie restorations. Invasion of the grasslands at both Lost Mound, a remnant sand prairie, and Midewin, a remnant tallgrass prairie, is a major management issue. The two sites differ in soil type, but otherwise offer unique and highly replicated microhabitats. Both sites include over 100 identical, equally spaced earth-covered storage structures built over 60 years ago. These structures are now vacant and have become incorporated into the grassland habitat. The structures are identically-oriented mounds that provide five different microhabitats with respect to aspect, soil moisture, and wind exposure. Each microhabitat thus offers distinct environmental conditions for plant invasion. We include both native and non-native woody plant species because much of the past work on invasive species focused on non-native species without comparative data on native species. Comparison of seed arrival and survival for native and non-native plants across a gradient of microhabitat conditions has strong potential to reveal critical differences in the invasion process that can be used to develop adaptive control strategies for non- native invasive species. Because both sites have similar land-use history over the past 60 years and provide this unique and highly replicated set of microhabitats for experimentation, our proposed study uniquely limits confounding factors and helps to pinpoint specific limitations or promoters of woody plant invasion.