Title of Presentation or Performance

Determining the Distribution and Abundance of Wintering Red-tailed Hawk Subspecies in Illinois

Major

Environmental Studies

Type of Submission

Poster

Type of Submission (Archival)

Event

Area of Study or Work

Biology, Environmental Studies

Expected Graduation Date

2023

Location

CNS Atrium, Easel 27

Start Date

4-9-2022 8:30 AM

End Date

4-9-2022 9:45 AM

Abstract

Determining the Distribution and Abundance of Wintering Red-tailed Hawk Subspecies in Illinois

Steven Burkett2, Rebekah Harden1, Miles Keeton2, Meredith Fraker1

and R. Given Harper*

Biology Department1 and Environmental Studies2 Program, Illinois Wesleyan University

Red-tailed Hawks (RTHA), which are one of the most common raptorial birds in North America, are often seen soaring or hunting from trees and the tops of utility poles. Five of twelve recognized subspecies winter in Illinois: Buteo jamaicensis borealis, the predominant subspecies found year-round in Illinois and eastern North America; B. j. calarus (breeds in western North America); B. j. kriderii (breeds in northern Great Plains and western Canada); B. j. harlani (breeds in Alaska); B. j. abieticola (breeds from New England to southeast Alaska; under consideration as a distinct subspecies). Few systematic efforts have been conducted to determine the winter distribution and abundance of RTHA subspecies within the state. Wintering RTHAs in Illinois were identified via analyses of photos of live-trapped hawks, photo submissions to eBird (a national repository of documented bird sightings in the U.S.), documentation in Vert Net (listing of RTHA study skins in museum collections), photos from private individuals, and winter raptor surveys. Preliminary analyses of photos (n = 390) indicate that B. j. borealis comprised 90.3% of sightings, followed by B. j. abieticola (3.5%), B. j. calurus (2.7%), B. j. harlani (2.7%) and B. j. kriderii (0.8%). Our analysis corroborates Wheeler’s (2018) distribution map for B. j. calurus and B.j. borealis, which winter throughout Illinois. However, the Wheeler distribution maps of wintering B. j. kriderii and B. j. harlanii only extended into the southwestern edge of Illinois. In contrast, our data indicate they winter northeast of Wheeler’s demarcation, extending into central and northern Illinois. These data can inform future conservation efforts and aid in understanding how climate change may alter the winter distribution pattern of RTHA subspecies in the midwestern U.S.

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Apr 9th, 8:30 AM Apr 9th, 9:45 AM

Determining the Distribution and Abundance of Wintering Red-tailed Hawk Subspecies in Illinois

CNS Atrium, Easel 27

Determining the Distribution and Abundance of Wintering Red-tailed Hawk Subspecies in Illinois

Steven Burkett2, Rebekah Harden1, Miles Keeton2, Meredith Fraker1

and R. Given Harper*

Biology Department1 and Environmental Studies2 Program, Illinois Wesleyan University

Red-tailed Hawks (RTHA), which are one of the most common raptorial birds in North America, are often seen soaring or hunting from trees and the tops of utility poles. Five of twelve recognized subspecies winter in Illinois: Buteo jamaicensis borealis, the predominant subspecies found year-round in Illinois and eastern North America; B. j. calarus (breeds in western North America); B. j. kriderii (breeds in northern Great Plains and western Canada); B. j. harlani (breeds in Alaska); B. j. abieticola (breeds from New England to southeast Alaska; under consideration as a distinct subspecies). Few systematic efforts have been conducted to determine the winter distribution and abundance of RTHA subspecies within the state. Wintering RTHAs in Illinois were identified via analyses of photos of live-trapped hawks, photo submissions to eBird (a national repository of documented bird sightings in the U.S.), documentation in Vert Net (listing of RTHA study skins in museum collections), photos from private individuals, and winter raptor surveys. Preliminary analyses of photos (n = 390) indicate that B. j. borealis comprised 90.3% of sightings, followed by B. j. abieticola (3.5%), B. j. calurus (2.7%), B. j. harlani (2.7%) and B. j. kriderii (0.8%). Our analysis corroborates Wheeler’s (2018) distribution map for B. j. calurus and B.j. borealis, which winter throughout Illinois. However, the Wheeler distribution maps of wintering B. j. kriderii and B. j. harlanii only extended into the southwestern edge of Illinois. In contrast, our data indicate they winter northeast of Wheeler’s demarcation, extending into central and northern Illinois. These data can inform future conservation efforts and aid in understanding how climate change may alter the winter distribution pattern of RTHA subspecies in the midwestern U.S.