eWestern BirdsThe Quarterly Journal of Western Field Ornithologists
Vol. 40, No. 1
Western Field Ornithologists
Nestling Provisioning by American Dippers near Juneau, Alaska
Mary F. Willson and Katherine M. Hocker
ABSTRACT: The rate of food delivery by male American Dippers (Cinclus mexicanus) increased as the female spent more time brooding young chicks, although the delivery rate by male parents varied greatly when the female was not brooding. Males commonly delivered food more often than females when females were brooding, but nonbrooding females sometimes made more deliveries than their mates. Pairs differed in the relative numbers of food-delivery trips by male and female. Juvenile salmon, and salmon eggs in season, were often delivered to chicks on streams with salmon spawning runs, by both parents. Single parents raised chicks successfully in three cases. One male mated bigamously, but only one of his females was successful in rearing chicks, probably because of a severe infestation of bird-blowflies.