Among James’ (male DC) prey this month are two young white-tailed deer. Yu-Cheng has also noted that DC takes two-toed sloths almost exclusively in one part of the island and mostly three-toed sloths in another. We have yet to determine if this is related to their relative densities.

Female MV inhabits a remote area of Camino de Cruces National Park. The very hilly area requires six or seven hours of hiking to reach her. We have useful data on her foraging behavior on the mainland and we hope to compare it with her behavior on Barro Colorado Island. Thus far, she eludes our attempts to trap her, often moving away at our approach.

This month we trapped female MV, now 22 months old and independent for the last ten months, and moved her to Barro Colorado Island (BCI) where she joins James (male DC). With luck they will form a pair in the years to come. Female MV is an accomplished huntress and has been observed taking Howler Monkeys, sloths, and various other prey on the mainland. She will provide us with the opportunity to compare her foraging habits in Soberania with her hunting habits on BCI. On BCI, the proportions of prey animals and the anti-predator behaviors of different animals, particularly primates, are different. Barro Colorado Island abounds with howlers and White-faced Capuchin monkeys, a favorite fare of female MV.

Our resident Barro Colorado Island (BCI) biologist, Yu-Cheng Hsu, returned to Taiwan, not having visited his home since the earthquake. Yu-Cheng logged a remarkably long uninterrupted field study of Harpy behavior on the Smithsonian research island. Notwithstanding the hardships of the rainy season and a case of Leishmaniasis (a dangerous disease contracted from sloths via a fly), Yu-Cheng hardly missed a day in the field. Treatment of Leishmaniasis includes 42 painful injections and Yu-Cheng even administered these in the field. The important data he collected on male DC was during a later phase of development when young Harpies begin to interact with primates seriously. With this daily record of activities and cycles of behavior we can better understand behavior and development of large avian predators.

Colorado biologist Janeen Touchton is continuing BCI observations on the two eagles with a special focus on female MV.

By Alberto Palleroni