Northern Bobwhite Population Characteristics, Productivity, and Hen Survival in West Central Louisiana

We examined aspects of northern bobwhite (Colinus virginianus; hereafter quail) population dynamics in longleaf pine (Pinus palustris) forests on the Vernon Ranger District, Kisatchie National Forest, located in west central Louisiana. We used sex, age, and weight data from 246 birds captured a total of 404 times during 9 February-20 June 1991-1993 in baited traps to describe population characteristics. We used data from 128 (106 F:22 M) birds trapped, radio tagged, and monitored during 3 field seasons to describe productivity and survival of these birds during March through August. The best-fit linear-logistic model (G2 = 7.42, 5 df, P = 0.1912) indicated that proportions of second year (SY) birds captured during spring depended on year; but sex ratios of captured birds were independent of year. Thus, we estimated that the breeding population contained 42.4 ± 3 . 1% (mean ± 1 SE) females and the proportion of SY birds varied among 62.5 ± 7.1%, 46.2 ± 5.3%, and 66.4 ± 4.6% during 1991, 1992, and 1993 respectively. Adult birds were consistently (no significant interactions with year or day, P > 0.1) 4.1 % heavier than SY birds (168 ± 1.2 g vs. 161 ± 1.1 g). We observed no difference in the relationship between body mass and sample date among years {P > 0.1), but females experienced a curvilinear change in mass compared to males, which decreased at a rate of 0.12 ± 0.03 g/day. Average clutch size for 39 completed nests pooled over years was 13.3 ± 0.4. Pooled estimated nest success was 48 ± 8%. Of 40 nests found, 19 produced hatchlings for an average production rate of 5.9 ± 1.0 hatchlings per clutch, but 12.4 ± 0.4 hatchlings per successful nest. Proportional hazards regression models indicated that hen survival was not affected by age (P = 0.25), but that hens were 1.8 times as likely to die (P = 0.05) during 1992 than during 1991 and 1993. Estimated 150-day (Mar-Jul) survival rates for hens were 16 ± 4% during 1992 and 36 ± 4% during 1991 and 1993, which were lower or similar to several other studies of breeding season mortality.

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