Nesting habitat and success of the Chimango Caracara in Southern Chile

We studied the nesting ecology of the Chimango Caracara (Milvago chi,nar Eg o), a common yet poorly known raptor on Chiloe Island, southern Chile, duri ng two breeding seasons. Deforestation and land clearing in this landscape may be benefiting this raptor, which is tolerant of open and disturbed habi tats and human activity. Chimangos nested at different heights in a variety of trees and shrubs, but nests were always well concealed because they wer e placed centrally and in dense vegetation within the substrate. Egg laying occurred in most nests in October during both years; the most common clutc h sizes were 2 or 3 eggs. The incubation and nestling periods were approxim ately 5 (2 nests) and. 6 (1 nest) weeks, respectively. Nest success (Mayfie ld) for 72 nests averaged 57% for the two years. Productivity averaged 1.22 +/- 0.11 Fledglings per active nest and did not differ between years. For nests located during both years (n = 15), productivity was slightly higher in 1997-1998 and more nests failed in 1998-1999. Two pairs attempted to ren est after nest failure but were not successful. Habitat and landscape featu res associated with high productivity of chimango nests included exotic tre es and shrubs, tidal Rats, linear forest strips, and occupied houses or bar ns. Successful nesting was associated with exotic trees and shrubs. Nesting density was highest along beaches, although not all pairs that built nests along beaches laid eggs. Successful nests along beaches fledged twice as m any young as inland nests. Continued clearing of the rainforest in this reg ion may provide increased foraging opportunities for this raptor but may al so result in fewer nest sites.