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1 November 2013 Food Availability Fails to Explain Asynchronous Breeding of Two Syntopic Oriental Trogons
James S. Steward, Philip D. Round, John R. Milne
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Seasonal variation in food supply may not adequately explain avian breeding phenology in tropical areas with relatively stable climates. In northeastern Thailand the Red-headed Trogon (Harpactes erythrocephalus) and Orange-breasted Trogon (H. oreskios) share similar nest sites, diets, foraging habitats, and foraging techniques but differ in timing of reproduction even though their food supply of insects varies in a similar seasonal pattern, peaking in June for both species. For the Red-headed Trogon, egg laying lasts 5–6 months and peaks in May; nestling provisioning coincides with peak food availability. For the Orange-breasted Trogon, by contrast, egg laying lasts 2–3 months and peaks in February. This nesting period is shorter and earlier than that of most other species of birds at our study site, and nestling provisioning preceded the period of peak food by 4 months. Timing of breeding by the Orange-breasted Trogon may represent a compromise between breeding at the optimal time based on food resources and avoiding competition for nest sites from the larger Red-headed Trogon.

© 2013 by The Cooper Ornithological Society. All rights reserved. Please direct all requests for permission to photocopy or reproduce article content through the University of California Press's Rights and Permissions website,
James S. Steward, Philip D. Round, and John R. Milne "Food Availability Fails to Explain Asynchronous Breeding of Two Syntopic Oriental Trogons," The Condor 115(4), 838-846, (1 November 2013).
Received: 22 January 2012; Accepted: 20 September 2013; Published: 1 November 2013
food availability
Harpactes erythrocephalus
Harpactes oreskios
nest-site competition
Orange-breasted Trogon
Red-headed Trogon.
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