Midwest Fish & Wildlife Conference 2019

AUTHORS: Maureen L. Hurd, Thomas J. Benson – Illinois Natural History Survey and Department of Natural Resources and Environmental Sciences, University of Illinois at Urbana-Champaign; Michael P. Ward, Department of Natural Resources and Environmental Sciences, University of Illinois at Urbana-Champaign

ABSTRACT: The Chimney Swift (Chaetura pelagica) is a bird species of conservation concern in Illinois and one of many aerial insectivores experiencing population declines across North America. While causes of declines are unknown, habitat availability and changes in insect populations are likely contributing factors. Chimney Swifts historically nested in tree cavities, but switched to nesting primarily in masonry chimneys as North American settlements expanded. With the growing trends of chimney caps and gas/electric heating, available chimneys are disappearing, and the loss of available nest sites may be driving Chimney Swift declines. Like other aerial insectivores, Chimney Swifts may also provide valuable pest control services and action may be needed to maintain this benefit. To investigate potential causes of declines in Illinois, we examined the influence of habitat and landscape factors on Chimney Swift abundance. We conducted surveys for swifts in 126 municipalities throughout Illinois and recorded the number of uncapped masonry chimneys at each survey point. We used these data along with landscape-level data such as composition of land cover surrounding points, areal extent of municipality, and age distribution of buildings. We found that 97% of municipalities were occupied by Chimney Swifts, but abundance varied considerably. Swifts were detected at 72.5% of survey points. Chimney Swift abundance was most heavily influenced by the number of uncapped masonry chimneys at survey points. Our results suggest that although Chimney Swifts are still widespread, contemporary building practices will continue to drive population declines and management should focus on approaches for providing and preserving suitable nesting sites.

AUTHORS: Bradley F. Blackwell, Morgan B. Pfeiffer, Travis L. DeVault, Thomas W. Seamans – USDA/APHIS/WS National Wildlife Research Center

ABSTRACT: Bird movements, particularly during migration, provide information on timing and species composition relative to climate change and population dynamics.  Movement data have been traditionally gleaned from observers for the North American Breeding Bird Survey (BBS) and Audubon Christmas Bird Count, and via band returns.  More recently, weather and avian radars are contributing movement data (not necessarily specie-specific), and citizen science is providing observation data via Ebird.  An untapped and publically available source of species-specific movement data is the U.S. Federal Aviation Administration’s Wildlife Strike Database.  From 1990–2016, 183,296 wildlife-aircraft collisions (strikes) were reported (179,542 in USA and 3,754 strikes by US-registered aircraft in foreign countries) to the FAA. Birds compose approximately 96% of reported strikes, and aircraft “sample” intensively a broad spectrum of altitudes and geography seasonally.  Approximately 529 bird species have been struck over the 27-year period.  Our purpose is to introduce this novel source of avian survey data as a potential compliment to current information on avian movements.  As such, we will discuss how strike data are collected, identified, reported, and inherent biases.  We will provide trends for March through July over the last ten years in reported strikes for six species (including a warbler, blackbird, shorebird, waterfowl, wading bird, and raptor) struck in the Mississippi Flyway and species relative strike frequency per the respective year.  We will relate these trends to the known spring migration movement timing and Ebird population trends for each species for the same region and period.  

AUTHORS: Brian Washburn, USDA Wildlife Services; Adam Phillips, USDA Wildlife Services; Siddhartha Majumdar, University of Illinois at Urbana-Champaign; David Mayer, University of Illinois at Urbana-Champaign; Ryan M. Swearingin, USDA Wildlife Services; Edwin Herricks, University of Illinois at Urbana-Champaign; Travis L. Guerrant, USDA Wildlife Services; Scott Beckerman, USDA Wildlife Services; Craig Pullins, USDA Wildlife Services

ABSTRACT: Avian radar technologies have the potential to serve an important role in the quantification of bird movements and determining patterns of bird use in areas where human–wildlife conflicts might occur (e.g., airports, wind energy facilities). However, capabilities and limitations of these technologies are relatively unknown and ground-truthing studies are needed to help wildlife managers understand the biological meaning of radar information. We evaluated the efficacy of 3 X-band marine radar sensors for tracking birds and flocks of birds observed on the airfield at Chicago’s O’Hare International Airport, USA, during March 2011−November 2012. Specific information regarding field observations of birds or flocks was used to determine how frequently the 3 radar sensors provided corresponding tracks of these avian targets. In addition, various factors were examined to determine if they had any influence on the frequency of correspondence between visual observations and radar tracks. Of the 972 sightings of individual birds (49%) or flocks of birds (51%) by observers on the airfield that had the potential to be observed by the radar, 141 (15%) were tracked by at least one radar sensor. All confirmed tracks of bird/flocks were ≤4.8 km from these radars. Among the 3 radar sensors, larger-bodied bird species, bird/flocks flying at higher altitudes, and bird/flocks closer to the radars increased the ability of those units to track avian targets. This study provides new information regarding the performance of radar systems for tracking birds on the airfield of one of the largest and busiest airports in the world.

AUTHORS: Ryan Askren, Mike Ward – Illinois Natural History Survey; Scott Beckerman, Craig Pullins – USDA Wildlife Services

ABSTRACT: Increasing abundances of Canada geese (Branta canadensis) wintering in urban areas have led to a host of human-wildlife conflicts including feces deposition, human health risks, and aircraft collisions. Harassment is the primary tool wildlife managers use to deal with nuisance goose abundances yet has been deemed ineffective at changing goose abundances in an area or reducing issues in longer time periods. However, the effects of harassment at the individual level are poorly studied, especially in winter when harassment may have more dire consequences. The objectives of this study were to examine the effects of targeted harassment on 1) average daily movement distances, 2) habitat use, and 3) overall dynamic body acceleration (ODBA) as an index of energetic expenditure. To examine effects of harassment on individual Canada geese we used data from 41 geese marked with GPS transmitters in the Chicago Metropolitan Area. Harassment efforts were conducted December 2017- February 2018 by US Department of Agriculture – Wildlife Services personnel at an urban park near Midway International Airport as part of ongoing efforts to reduce risk to air traffic. We compared average daily movement distance and ODBA of geese that in and out of harassment areas. In addition, we quantified differences in proportional habitat use of geese between treatments. Canada geese subjected to harassment moved more than unharassed geese in December (x¯_harassed= 338.2 ± 19.3 SE, x¯_unharassed= 211.3 ± 8.4 SE), January (x¯_harassed= 409.0 ± 2.5 SE, x¯_unharassed= 269.0 ± 11.0 SE), and February (x¯_harassed= 447.0 ± 36.4 SE, x¯_unharassed= 232.8 ± 13.5 SE). Results of this study suggest that winter harassment of Canada geese in winter has effects on the behavior and energetic expenditure that could result in lower survival and reduced conflicts in urban parks where targeted harassment is conducted.