Effects of Nest and Brood Visits and Radio Transmitters on Rock Ptarmigan

Abstract

The effect of researchers on animal behavior and survival has received attention, and avian studies have reported results ranging from few effects to decreases in reproductive success and survival. We examined potential effects of researchers'nest and brood visits on rock ptarmigan (Lagopus mutus) survival and breeding success and the effects of radio transmitters on ptarmigan survival in the central Canadian Arctic in 1988-89. Predation rate of hens (P = 0.92), clutch size (P = 0.28), number of chicks leaving the nest (P = 0.93), and nesting success (P = 0.86) did not differ between disturbed (flushed hen off nest) and undisturbed (determined hen's status on or off nest by telemetric triangulation) nests. Brood size at fledge (P = 0.89) and fledging success (P = 0.14) did not differ between broods that were visited frequently (every 3-4 days) or infrequently (every 6-9 days). Approximately half (n = 27) of the males captured and banded were fitted with radio transmitters. Survival of radio-marked males (S = 0.62) was lower than that of unmarked males (S = 1.00) in 1988 (P = 0.03) and for years pooled (radiomarked, S = 0.55; unmarked, S = 0.83; P = 0.008), but not in 1989 (P = 0.11). Transmitters weighed more in 1988 than 1989 (3.6 vs. 2.3% body mass, respectively). Studies should consider potential effects of researchers and test for them to detect biases that may exist and to develop methods and equipment that have minimal effect on the study animal