Fig. 1
From: Female begging calls reflect nutritional need of nestlings in the hen harrier Circus cyaneus
Patterns of food deliveries and female begging at hen harrier nests. a shows variation in grams of food delivered to nests with (F) and without (U) access to adlib food during the nestling stage (1998 & 1999 data). b shows the relationship between female begging rate and the age of chicks in weeks. c shows the relationship between female begging rate and brood size. d shows the relationship between male provisioning rate (g per hour) and average female begging rate per 6 h watch, with the fitted line showing model output, controlling for chick age and number. e shows the effect of experimental feeding on average female begging over the nestling period. Figs show data from individual watches with means (filled circles) in a, b, c & e