NESTLING HUNGER AND PARENTAL CARE IN RED-WINGED BLACKBIRDS

We examined the influence of nestling hunger and the settlement of add itional mates on the parental behavior of polygynous male Red-winged B lackbirds (Agelaius phoeniceus). When brood size and nestling age were held constant, the begging behavior of food-deprived nestlings caused most males to begin provisioning nestlings. Males were not influenced by the presence of additional females settling on the territory. Male s that did not respond to nestling hunger had a fertile female mate. I n response to satiated nestlings, males stopped provisioning. These re sults suggest that polygynous male Red-winged Blackbirds may be withho lding parental care at one nest in order to protect paternity at anoth er nest. Females increased provisioning to food-deprived nestlings and reduced provisioning to satiated nestlings. Changes in female provisi oning rate were associated with changes in foraging habitat and volume of prey delivered to nestlings.