Demography of Northern goshawks in northern Arizona, 1991-1996

Abstract

We studied 282 nesting attempts on 107 territories of Northern Goshawks (Accipiter gentilis) on the Kaibab Plateau in northern Arizona from 1991–1996. Mark-recapture methods were used to estimate recruitment, turnover of adults on territories, fi delity to territories by adults, and apparent annual survival of breeding adults. Territories were regularly spaced at a mean nearest-neighbor distance of 3.9 km. Annual proportion of pairs breeding and recapture rates were high in 1991–1993, sharply declined in 1994, and partially recovered in 1995–1996. Average annual turnover of breeding goshawks was 42% for males and 25% for females. Breeding males stayed on their territories from one breeding year to the next in 97% of cases and females in 95% of cases. Of 64 capture-recapture models evaluated in program SURGE, the model with the lowest AIC {Phis, Pt} showed that, while survival differed between genders, it was constant for both genders over years. Probability of recapturing a goshawk varied with time (0.15 in 1994; 0.66 in 1992) but not with gender; recaptures were lowest in years when few of the territorial goshawks nested and highest when the majority of pairs nested.

Citation

Reynolds, Richard T.; Joy, Suzanne M. 2006. Demography of Northern goshawks in northern Arizona, 1991-1996. Studies in Avian Biology. 31: 63-74.