INVESTIGATION

THE BIRDS OF ACOSTA

On last November 05 we fulfilled a tour of study to The Agua Buena Range, in order to take some photography of birds for the publication of the bulletin with information about Birds of Acosta. In the beginning of the Range, exactly in the place known as The Shell (La Concha) we had, perhaps, the best observation of the tour, a couple of Bat Falcon (Falco rufigularis).

Two individuals were perching on a Encino tree without leaves and green (Quercus sp) it is at the edge of an isolated area of trees, where they were going out doing flights similar to the White-Collared Swift (Streptoprocne zonaris) (Stiles and Skuth 1995). We were observing them for a period of five hours and we had the opportunity to contemplate their behavior. They were sharing the perch with a Black Vulture (Coragyps atratus) and they were not presenting nuisance of anyone for the presence of both, only we observed an individual once struggling in flight with an Asturina nitida (Graw Hawk) but it was for a little time and eliminating the Hawk of the zone. They were flying over a group of not very numerous of Turkey Vulture (Cathartes aura) and Black Vulture.

The zone where they were observed is characterized for having a line of Steep rocks of approximately 100 meters high in its average part, covered by Agaves, Clusias and grassland. There we could observe certain quantity of small vertebrates and other types of small birds.

One week later (12/11/05) we visit again the place meeting two individuals in the same place and the same behavior, we think the same, we will continue with the observation of two individuals to know more on they development in the place, having the hope that they are resident. The Shell (La Concha) is located in front with the Steep rocks of the Hill Dragon forming a depression where we could have observed in other occasions others Raptors and Kites as the American Swallow-tailed Kite (Elenoides forficatus). So our interest of preservation the place and iis surroundings.

Paula Calderón M. and Warren Umaña C.

Biologists of the University of Costa Rica

Adilio Antonio Zeledón M.

Observer and annotator