Midwest Fish & Wildlife Conference 2019

AUTHORS: Tom Will, U.S. Fish and Wildlife Service

ABSTRACT: Since its inception in 1990, Partners in Flight (PIF) has taken progressive steps to provide useful range-wide landbird conservation vulnerability assessment at both continental and Bird Conservation Region (BCR) scales. The 2016 Landbird Conservation Plan for Canada and the U.S. introduced new metrics designed to more effectively communicate the urgency of addressing precipitous declines of both range-limited and wide-ranging common species—notably the concept of a "half-life": the forecasted number of years when an abundance that is half the current abundance is reasonably expected to be observed. PIF has also redesigned its website to make it easier to access all of its tools, including its Technical Series, Species Assessment database, Population Estimates database, regional and national conservation plans, and access to its email information and announcement list-serves. Highlighting communication with partners, the revised website provides a platform for exploring and distributing other recent Partners in Flight developments. The Species Assessment, renamed the PIF Avian Conservation Assessment Database (ACAD), now covers all taxa—landbirds, shorebirds, waterbirds, and waterfowl—for over 1600 species from Canada through Panama. The Population Estimates database now provides upper and lower uncertainty bounds around its median U.S./Canada breeding adult population size estimates at state-x-BCR scales. As part of the 2016 Plan, PIF offers recommendations for U.S./Canadian planning unit responsibility for recovering Watch List species and, by incorporating global eBird data, identifies areas of greatest importance for migrants during the non-breeding season to facilitate full life cycle conservation. Finally, a thorough partner review of all regional-scale (BCR) breeding season assessment scores in the U.S. and Canada has just been completed and is now live via the website. The revised regional breeding season assessment provides recommendations reflecting Midwest contributions toward continental bird conservation and identifies regionally important species and regional stewardship responsibilities using a standardized and quantitative methodology.

AUTHORS: Evalynn M. Trumbo, Michael P. Ward, Jeffrey Brawn – University of Illinois

ABSTRACT: Understanding associations between habitat and the demography of endangered wildlife is essential for effective management, and the age or life-stage of an individual adds complexity to these associations. The Golden-cheeked Warbler (Setophaga chrysoparia; hereafter "warbler"), is an endangered neotropical migrant that breeds only in the contiguous juniper-oak forests in central Texas, of which many studies have evaluated how extensive habitat loss and fragmentation affect adult demography, yet no research has been conducted on post-fledging life stages and their habitat preferences, specifically microhabitat. For birds, the post-fledging stage is critical for sustaining species’ populations and many threats to survival during this life-stage are influenced by habitat type. To understand survival and habitat use, we studied the warbler population at Fort Hood military installation in central Texas. We monitored warbler nests until fledging and deployed one VHF transmitter per nest (n=8 and n=15, for 2017 and 2018, respectively). We tracked fledglings ~4 weeks after fledging. 15 of 23 (65%) of the fledglings survived the observation period. We obtained 1126 vegetation samples measuring various habitat characteristics for the entirety of the study (2017-2018). We compared habitat measurements between fledgling locations and random locations away from the fledgling location. Fledglings appear to select habitat that contains higher canopy cover (86% ± 0.6%, vs. 77% ± 1%). Ground cover, although correlated with canopy cover, differs from non-used habitat (29% ± 0.9%, 37% ±1.05%). Vertical vegetation density in the understory does not differ among used and non-used habitat. Most likely fledglings are selecting for canopy cover since it affords more protection from predators. Using this information for habitat selection will allow managers to implement techniques that promote higher canopy cover in GCWA habitat, hopefully providing a mosaic of necessary traits to support all life stages during the breeding season.

AUTHORS: Stephen A. Tyndel, University of Illinois at Urbana-Champaign; Dr. Jinelle Sperry – CERL-ERDC, University of Illinois at Urbana-Champaign; Dr. Michael P. Ward, University of Illinois at Urbana-Champaign, Illinois Natural History Survey

ABSTRACT: Blue-winged Warblers (Vermivora chrysoptera) and Golden-winged Warblers (Vermivora cyanoptera) are closely related species that hybridize frequently and produce fertile offspring yet tend to mate assortively and often hold overlapping territories. Information on how conspecific and heterospecific interactions impact settlement and habitat selection for both species is lacking.The purpose of this study was to examine the role of social information, specifically song, in habitat selection in both Blue-winged and Golden-winged warblers. Our first objective was to determine if conspecific and heterospecific song can be used to induce settlement in Blue-winged and Golden-winged warblers across their range and whether the response of each species to heterospecific song differs in allopatric and sympatric populations. Our second objective was to determine whether Blue-winged and Golden-winged Warblers males discriminate against heterospecific song and whether discrimination against heterospecific song differs in in allopatric and sympatric populations. To address the first objective, we broadcast songs of Blue-winged warblers and Golden-winged warblers in an area where only Blue-winged warblers breed, where only Golden-winged warblers breed, and where both species breed. To address the second objective, we conducted a simulated territorial intrusion experiment to compare how breeding territorial males of each species respond to heterospecific song in an area where only Blue-winged warblers breed, where only Golden-winged warblers breed, and where both species breed. Data analysis is ongoing but preliminary results for the first objective suggest the strongest response to conspecific cues occurred in the allopatric population of Golden-winged warblers with equivocal results found elsewhere. Responses to heterospecific cues were similarly ambiguous. Preliminary results for the second objective suggest strong species discrimination in sympatry and weak discrimination in allopatry. Ultimately our results will provide important insight into the relationship between these species and the role of social information in habitat selection.

AUTHORS: Benjamin W. Tjepkes, Stuart C. Fetherston, Scott E. Hygnstrom – Wisconsin Center for Wildlife, College of Natural Resources, University of Wisconsin-Stevens Point; Brian J. Stemper, Stephen L. Winter – Upper Mississippi River National Wildlife and Fish Refuge, U.S. Fish and Wildlife Service

ABSTRACT: The overall population of bald eagles (Haliaeetus leucocephalus) has increased in range and size across much of North America, since they were listed as a federally Threatened Species in the 1970’s.  This increase likely is due in part to the efforts of several federal and state wildlife management agencies in protecting nest sites, an important factor in raptor reproduction.  We studied nest-site selection in bald eagles along the 420-km long Upper Mississippi River National Wildlife and Fish Refuge using survey data from 1990 – 2012.  Spatial analyses were conducted on known active nest locations using a GIS to develop several metrics relating to bald eagle nesting ecology (e.g., distance to water, surrounding cover type, patch size) and several disturbance metrics (e.g., distance to navigable channel, distance to road).  These metrics will then be used to build a mixed-effects resource selection function under a use-availability design for this population.  This information will increase the understanding of how bald eagles occupy habitats along the Upper Mississippi River in relation to habitat features and human activities, further contributing to the effective management of this species.

AUTHORS: Luke J. Malanchuk, Michael P. Ward – Illinois Natural History Survey; Heath M. Hagy, U.S. Fish & Wildlife Service; Aaron P. Yetter, Forbes Biological Station, Frank C. Bellrose Waterfowl Research Center

ABSTRACT: The Illinois River Valley (IRV) serves as a crucial stopover area for migratory shorebirds in the midwestern United States despite the high prevalence of row crop agriculture and extensive  wetland loss and degradation in the region. Aerial surveys are commonly used to quantify waterfowl abundance and estimate population size, but few attempts have been made to evaluate aerial surveys for other guilds of wetland birds. We investigated whether aerial surveys may provide a good estimate of shorebird use of stopover sites in the IRV. During July-September 2017-2018, and April-May 2018, we conducted concurrent ground and aerial surveys at 5-7 sites per week. Additionally, a single observer counted and assigned all shorebird detections to either "large" (Killdeer (Charadrius vociferous) and larger) or "small" (Pectoral sandpiper (Calidris melanotos) and smaller) size classes, and recorded wetland habitat characteristics at a total of 96 surveyed sites in the IRV. The use of ground counts each survey allows for the calculation of aerial detection probability count bias, while using habitat data of the specific count location from the ground as a correction factor. Aerial surveys detected 89% (N = 93, Range = 0%-250%) of individuals counted during ground surveys. The total number of shorebirds counted in the IRV each week ranged from 1,705 to 30,290, with an average of 10,025 birds. Aerial surveys appear to be an accurate and efficient method to quantifying shorebird abundance along large-river systems. Future plans include questions associated with stopover duration and which species are present in the IRV.