Hatching Synchrony, Green Branch Collecting, and Prey Use by Nesting Harpy Eagles (Harpia harpyja)

We observed an occupied Harpy Eagle (Harpia harpyja) nest over three separate periods in eastern Venezuela. Both eggs in the clutch hatched on the same day, and two nestlings competed in the nest for 14 days before one succumbed. The female adult collected green branches 45 times over 60 days of observation. Green branch deliveries were positively associated with prey deliveries and our observations best support the 'nest sanitation by covering prey' hypothesis for the adaptive significance of green branch collecting. Prey delivery rate to the nest averaged one delivery every 2.4, 2.1, and 3.7 days in the three observation periods. Three-toed sloths (Bradypus tridactylus) and wedge-capped capuchins (Cebus olivaceus) were the most common prey items brought to the nest. Received 14 April 2010. Accepted 23 July 2010.