Nonbreeding Season Survival and Habitat Selection of Northern Bobwhite in Northeastern Colorado

Authors

Joseph M. Wolske, University of Nebraska - LincolnFollow

First Advisor

Larkin A. Powell

Second Advisor

Adam C. Behney

Date of this Version

8-2022

Citation

Wolske, J. M. 2022. Nonbreeding survival and habitat selection of northern bobwhites in northeast Colorado. Thesis, University of Nebraska, Lincoln, USA.

Comments

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: Natural Resource Sciences, Under the Supervision of Professors Larkin A. Powell and Adam C. Behney. Lincoln, Nebraska: August, 2022

Copyright © 2022 Joseph M. Wolske

Abstract

Northern bobwhites (Colinus virginianus) have experienced range-wide population declines. Recent harvest data from northeastern Colorado suggests bobwhite populations have declined and populations can be sensitive to adult nonbreeding season survival. We monitored 157 bobwhites in northeastern Colorado, on the northern periphery of the species’ range, for the 2019-2020 and 2020-2021 nonbreeding seasons to estimate nonbreeding season survival and habitat selection. We used known-fate survival models to assess any variation in survival between the winter stages of early-winter, mid-winter, and late-winter, as well as sex, age class, and mass at the time of capture. Survival varied among winter stages, with the period having the lowest survival corresponding with the harshest weather conditions. We also monitored bobwhite habitat selection by performing weekly covey habitat surveys to collect vegetation cover percentages, micro-climate variables, vegetation structure variables, and plant species richness estimates at used and random sites. We used stepwise backward selection modeling to determine if any variables were being selected disproportionate to their availability. Bobwhites chose locations with higher levels of visual obstruction, percent bare ground and percent litter cover Winter survival was low in our study and dependent on weather conditions and predation. Habitat management has the potential to reduce the risk of nonbreeding season mortality for bobwhites, which is critical to sustain local populations at the northwestern edge of the species’ range. Our research aims to provide demographic and habitat selection data to managers to assist them in management action decision making.

Advisors: Larkin Powell and Adam Behney