FINAL REPORT
State of Oklahoma
Grant Number W-82-R
Project Number 009
Grant Title: Upland Game Investigations
Grant Period: July 1, 1997- June 30, 2002
Project Title: Northern Bobwhite Chick Ecology Study
Project Objective: To determine the feasibility of using micro transmitters on northern bobwhite chicks and determine the earliest optimum age at which chicks can be marked. To collect data during the critical brood-rearing period which will provide information on survival, mortality, identification, and help to identify and understand production mechanisms that affect fall populations.
Abstract: In 1991, the Oklahoma Department of Wildlife Conservation initiated a 10-year study of northern bobwhites (Colinus virginianus; hereafter, bobwhite) to obtain information applicable in understanding and managing mid-latitude populations. We report on aspects of chick ecology (survival, cause-specific mortality, and growth rates) during 1997-2002. Survival est1mates were sensitive to censor-period length. Survival became time independent at around 30 days post capture. Annual survival with a 30-day censor period was 2.5%, which converts to a daily survival rate of 0.9899. The proportion of deaths attributed to various causes was independent of censor-period length (G = 21.9, P>O.O5). Raptor predation (21.5%) was the largest source of loss. Capture- (13.5%) and col1ar-related (4.5%) losses occurred after subsequent recaptures. That is, 26% of bobwhite chicks that succumbed to radio attachment did so after having their radios replaced upon recapture. Twelve percent of bobwhite chicks were never relocated after transmitter attachment and were assumed to have dispersed. Mammals killed 14.5% of radioed bobwhite chicks over the span of the study. Mass was a logistic function of age. Differentiating this function revealed that bobwhite growth rate peaked at 2.96 g/day at 36
days of age. The extremely low annual survival estimate obtained in this study suggests that radiotagging might adversely affect survival. Therefore, when applying the results of radiotelemetry studies to wildlife-population management, it would be prudent to use caution when interpreting the results.
REPORT CONTENT:
The following manuscript, prepared for submission to the Journal of Wildlife Management, details study methodology, results, discussion and management implications derived from this study.