Biological Sciences, School of


First Advisor

Dr. John P. DeLong

Second Advisor

Dr. Daizaburo Shizuka

Third Advisor

Dr. Joseph J. Fontaine

Date of this Version

Spring 4-24-2020


Pokharel, Anisha. "Prey Selection by Birds of Prey" (2020).


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

Copyright © 2020 Anisha Pokharel


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 hawksand 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