Prey Selection by Birds of Prey

Authors

• Anisha Pokharel, University of Nebraska-LincolnFollow

First Advisor

John P. DeLong

Committee Members

Daizaburo Shizuka, Joseph J. Fontaine

Date of this Version

4-2020

Document Type

Thesis

Citation

A thesis presented to the faculty of the Graduate College at the University of Nebraska in partial fulfillment of requirements for the degree of Master of Science

Major: Biological Sciences

Under the supervision of Professor John P. DeLong

Lincoln, Nebraska, April 2020

Comments

Copyright © 2020, Anisha Pokharel. Used by permission

Abstract

Prey selection is key to determine predator prey interaction and understanding the complexity of food web structure. In this thesis, we used two different approaches to understanding prey selection by North American birds of prey. Using a conventional method, in Chapter 1 we compared pellet analysis and trapping data to assess patterns of prey selection of barn owls in western Nebraska. Microtus spp. comprised 55.8% of the prey items in the barn owl’s diet. The proportion of several prey types in the diet were significantly different from the expected proportion based on trapping. This pattern may indicate barn owls actively select Microtus spp., possibly because they are a relatively more energetically rewarding prey. In Chapter 2, we quantified the prey selection of migrating Sharp-shinned hawks and Cooper’s hawks using DNA barcoding. Red-winged blackbirds (Agelaius phoeniceus) and rock pigeons (Columba livia) were the most common prey of Cooper’s hawk, and American robins (Turdus migratorius) were the most common prey of sharp-shinned hawks. Our results indicate that these raptors tend to consume relatively common prey species, possibly reflecting an energy conserving migration strategy. Detailed understanding of raptor diet is essential to identify their potential vulnerabilities and to develop effective conservation strategies.

Advisor: John P. DeLong