OBSERVATIONS ON SOME KENYA EAGLES

• Published in: Ibis
• Main Author: Brown, L. H.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1966
• Subjects: Eagle Hill; Falco peregrinus
• Online Access: http://dx.doi.org/10.1111/j.1474-919x.1966.tb07208.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1474-919X.1966.tb07208.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1474-919X.1966.tb07208.x

SUMMARY This paper describes the continuation of work on eagles in Embu district, Kenya, especially at Eagle Hill, which has now been under observation continuously since 1949. Observations in other parts of Kenya have been included. The ecological changes possibly affecting eagles on Eagle Hill are discussed. The population fell from a pair each of Circaetus cinereus, Aquila verreauxi, Hieraetus fasciatus spilogaster, H. dubius, Polemaetus bellicosus and Stephanoaetus coronatus in 1952 to a pair each of H. dubius, P. bellicosus and S. coronatus in 1965. Possible causes of the decline are discussed. The species of eagles are not normally aggressive to one another, in contrast to other resident species such as Falco peregrinus and Buteo rufofuscus. Although the eagles appear to be ecologically separated by food preferences and habitat this is apparently not the whole explanation for the unusual concentration of eagles on this hill. Additional breeding data are given for H.f. spilogaster, H. dubius, P. bellicosus and S. coronatus. These species rear respectively 0.56, 0.65, 0.42 and 0.44 young per pair per annum. S. coronatus breeds in alternate years and cannot breed every year because of a protracted post‐fledging period in which the young is fed for up to 350 days. P. bellicosus, with about the same annual reproductive rate, does not have the same breeding rhythm. Data on reproductive rates combined with other data suggest possible life spans in the wild state of adults of H.f. spilogaster 10–11 years, H. dubius nine years, P. bellicosus 14 years, and S. coronatus 16 years. At nests of H. dubius and S. coronatus changes of mates have been recorded for 16 and 17 years respectively. In S. coronatus a change occurs about every six years and in H. dubius about every four years, indicating that S. coronatus may live about 1.5 times as long as H. dubius in the wild state. One female S. coronatus was known to live for 8.5 years as an adult. Other incomplete life spans are eight and eight years for two male S. ...