Abstract

Northern Bobwhite (Colinus virginianus) populations have been declining over much of their range, but some of the steepest declines have been documented in New Jersey. Negative population trends in New Jersey and elsewhere have been attributed to a reduction in habitat quality and quantity. Managers in New Jersey are interested in how additional aspects of bobwhite ecology and demography may be mitigating or aggravating bobwhite declines. I conducted a two year (2006–2007) breeding season (1 May-30 September) telemetry study in southern New Jersey to collect baseline data on bobwhite movement, habitat selection, survival, reproductive rates, and nest and brood microhabitat. Pooling data between 2006 and 2007, I recorded 2,513 locations on 80 radiomarked bobwhites. Mean hourly movement rate (HMR) between consecutive day locations was 6.29 ± 0.49 m/h (n = 21 bobwhites). I observed 11 extreme movements, the greatest of which was 12,372 m in 169.8 h. Breeding season 95% adaptive kernel home ranges averaged 38.7 ± 6.1 ha (range 8.5–112.3 ha, n = 27 bobwhites). In order of greatest to least relative selection within the home range, bobwhites used scrub-shrub, followed by mixed grass, forest, agriculture, and other habitats. Breeding season survival was 0.343 ± 0.064 (95% CI 0.238–0.493, n = 80 bobwhites), and mortality risk did not differ by age, sex, year, or HMR (P > 0.242). I located 23 bobwhite nests and 21 were usable for survival analyses. Incubation period nest survival rate was 0.454 ± 0.010 (95% CI 0.280-0.727). Mean clutch size was 14.2 ± 0.58 (range 10-19, n = 20) and hatchability in successful nests was 96.1 ± 2.0% (range 86-100%, n = 10). The estimated probability an individual that entered the breeding season would initiate incubation on ≥ 1 nest was 0.687 for females and 0.202 for males. Nest microhabitat selection was positively related to visual obstruction and percentage of litter. Brood microhabitat selection was positively related to visual obstruction, vegetation height, and percentage of forb but negatively related to percentage of cool season grass and litter. Ecological and demographic parameters for bobwhites in southern New Jersey appear to be similar to those reported elsewhere in the species’ range. Management efforts to improve bobwhite in southern New Jersey should focus on increasing the quantity of available breeding and brood-rearing habitat.