Evol Ecol Res 9: 157-167 (2007)     Full PDF if your library subscribes.

Adaptation in the Hawaii akepa to breed and moult during a seasonal food decline

Leonard A. Freed,* J. Scott Fretz‡ and Matthew C. Medeiros

Department of Zoology, University of Hawaii at Manoa, Honolulu, HI 96822, USA

Author to whom all correspondence should be addressed.
e-mail: lfreed@hawaii.edu


Question: How can a bird breed and moult during a seasonal food decline?

Hypothesis: Nestling overgrowth (weighing more than adults by storing fat) during the period of relative plenty enables parents to bank their parental care in the bodies of their nestlings for use when they are fledglings during leaner times when the parents are moulting.

Organism: Hawaii akepa (Loxops coccineus coccineus).

Field site: Hakalau Forest National Wildlife Refuge, Mauna Kea, Island of Hawaii, HI, USA.

Methods: We documented breeding, moulting seasonality, and seasonality of canopy arthropods of Metrosideros polymorpha. We weighed and measured nestlings and fledglings to document ontogeny. We tracked fat and mass changes of adults and offspring throughout the 4-month long fledgling period to assess condition in relation to food availability.

Conclusion: Nestling overgrowth is the outcome of an adaptation of offspring to consume and use more than they need at the time and of parents to provide that additional food. The newly documented role of overgrowth enables fledglings to continue to grow while parents are heavily moulting primary flight feathers during deteriorating food availability.

Keywords: breeding season, moult–breeding overlap, nestling overgrowth.

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        © 2007 Leonard A. Freed. All EER articles are copyrighted by their authors. All authors endorse, permit and license Evolutionary Ecology Ltd. to grant its subscribing institutions/libraries the copying privileges specified below without additional consideration or payment to them or to Evolutionary Ecology, Ltd. These endorsements, in writing, are on file in the office of Evolutionary Ecology, Ltd. Consult authors for permission to use any portion of their work in derivative works, compilations or to distribute their work in any commercial manner.

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