Theses and Dissertations

Date of Award


Document Type


Degree Name

Master of Science (MS)



First Advisor

Dr. Robert K. Dearth

Second Advisor

Dr. Timothy Brush

Third Advisor

Dr. Teresa P. Feria Arroyo


Using GPS-GSM transmitters I determined when 14 juvenile Gray Hawks (Buteo plagiatus) in the Lower Rio Grande Valley of Texas fledged from their natal areas and how far they traveled once they dispersed. These transmitters also allowed me to calculate home range sizes for 22 adults. Additionally, with the GPS-GSM transmitters and 15 VHF transmitters, I discovered that adult Gray Hawks in the study area remained in their territories year-round. Home range sizes were calculated using the minimum convex polygon estimator, the estimation of kernel home-range, and the estimation of kernel Brownian bridge home-range. The same three methods allowed me to calculate the size of winter territories for 11 juveniles.

This information will help guide conservation efforts for Gray Hawks in Texas where they are a Species of Greatest Conservation Need.


Copyright 2021 Michael Stewart. All Rights Reserved.