Little is known about how variation in nestling begging affects the behavior of adult raptors and how responses of adult males and females might differ. Our objective was to manipulate the begging intensity of nestling American Kestrels (Falco sparverius) to examine the responses of adult males and females. We studied 12 pairs of kestrels and their broods from 1 May – 1 July 2014 in Madison County, Kentucky. To manipulate hunger levels, nestlings were fed until satiated and deprived of food. The begging behavior of 12-26-day-old nestlings and provisioning behavior of adults were video-recorded prior to (control) and after treatments. Proportion of nestlings begging did not differ at adult arrival, but differed at adult departure (F2,19 = 13.79, p = 0.0002). Intensity of begging differed at both arrival (F2,19 = 9.93, p = 0.0011) and departure (F2,19 = 15.96, p \u3c 0.0001), and nestling vocalizations in absence of a parent differed among treatments (F2,19 = 5.87, p = 0.0104). In response to treatments, adults increased and decreased their provisioning rates (F2,19 = 10.36, p = 0.0009). Adults visited food-deprived nestlings (4.164 visits/nestling/hour) four times the rate for nestlings that were fed to satiation (1.068 visits/nestling/hour). Adult males and females provisioned at similar rates (F1,57 = 2.770, p = 0.1014). The begging behavior of nestling American Kestrels varies with hunger level and is an honest signal of need. Adult kestrels interpret begging signals and respond by modifying their provisioning rates, and male and female kestrels respond to nestling signals in similar ways
