Birds of Indian Subcontinent

A Fledgling-mass Threshold Greatly Affects Juvenile Survival in the Hawaii Akepa (Loxops coccineus coccineus) (Un Umbral en la Masa de los Volantones Afecta Fuertemente la Supervivencia de los Individuos Jóvenes en Loxops coccineus coccineus)

Publication Type:Journal Article
Year of Publication:2009
Authors:Medeiros, MC, Freed, LA
Journal:The Auk
Date Published:2009
ISBN Number:00048038
Keywords:Fringillidae, indicator, Loxops, Loxops coccineus
Abstract:Abstract Offspring quality is an important issue in avian life-history theory, particularly with regard to birds that have low reproductive rates and extended parental care. Offspring mass has been identified as an indicator of quality in several bird species. These studies have shown that nestling mass is predictive of offspring survival outside the nest, but few studies have considered the role of fledgling mass. Mass during the fledgling period may change and influence juvenile survival. Fledgling mass may be especially relevant for tropical birds that have very long fledgling periods during which food conditions randomly or seasonally change. Here, we show that fledgling mass predicts juvenile survival in the Hawaii Akepa (Loxops coccineus coccineus), an endangered Hawaiian Honeycreeper with high annual adult survival and a two-egg clutch. Juvenile survival of Hawaii Akepa approximated a trimodal pattern of no survival, low survival, and high survival that corresponded to ascending mass classes. Fledglings in the highest mass class had an apparent juvenile survival probability that was more than double that of fledglings of the lower mass classes and that was statistically indistinguishable from survival rates of adults. This mass-dependent juvenile survival has important implications for understanding the life-history evolution and population biology of the Hawaii Akepa and perhaps of other tropical birds.
Short Title:The Auk
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith