Breeding biology and behavior of the Collared forest-falcon (Micrastur semitorquatus) in Guatemala

Collared Forest Falcon (Micrastur semitorquatus) Science Article 1


We studied Collared Forest-Falcons Micrastur semitorquatus in Tikal National Park, Guatemala from 1988 through 1993, documenting 9 nesting attempts. The Collared Forest-Falcon is a year-round resident, nesting in pre-existing cavities in large trees. Breeding commenced during the middle of the dry season. Egg laying occurred early March to early April, with laying peaking in early March and spanning 30 days (n= 8 clutches), with one exceptionally late laying date in May. The incubation period was 46-48 days at 1 nest and nestlings fledged on average at 50 days of age (n = 5). Only females incubated while males provided food until the mid-nestling period when the females began hunting and delivering prey to the young. Young fledged in June, early in the rainy season and were not observed again at the cavity. Of 16 eggs laid in 8 nests (mean = 2.0), 10 of 16 (63%) hatched, and 8 (80%) of those hatchlings fledged. The only reproductive losses resulted from egg depredation (n = 2 nests). The breeding period of the Collared Forest-Falcon lasted approximately 28 weeks from courtship to fledgling dispersal, long in comparison to similarly sized temperate raptors.

Russell Thorstrom, Jose D. Ramos & Jose M. Castillo, ORNITOLOGIA NEOTROPICAL 11: 1112

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