AVIS-IBIS

Birds of Indian Subcontinent

Behavioral and Morphological Correlates of Heterochrony in Hispaniolan Palm-Tanagers

Publication Type:Journal Article
Year of Publication:1994
Authors:McDonald, MA, Smith, MH
Journal:The Condor
Volume:96
Issue:2
Date Published:1994
ISBN Number:00105422
Keywords:Corvidae, Corvus, Corvus capensis, Corvus corone, Corvus tristis, Phaenicophilus, Phaenicophilus palmarum, Phaenicophilus poliocephalus, Poliocephalus, Thraupidae
Abstract:We documented the occurrence of heterochrony for morphological and behavioral characters in two species of Hispaniolan Palm-Tanager. Phaenicophilus palmarum is age-dimorphic in morphology and foraging behavior with 55% (n = 126) of specimens classified as juveniles. Juveniles differed from adults of their own species in five of eight foraging variables, average flight distance during a foraging bout, foraging height, use of broadleaf instead of pine substrates, and the presence of a gray instead of black crown. Phaenicophilus poliocephalus have gray crowns similar to those of P. palmarum juveniles and do not differ significantly from them for any of the eight foraging variables measured, choice of substrate, or average flight distance. They do differ from adult P. palmarum for four of eight foraging variables, average flight distance, and use of substrates. Phaenicophilus poliocephalus lacks a significant age-dimorphism in all behavioral and morphological characters measured. We classified only 15% (n = 66) of the specimens examined as juveniles based on morphology. This species tends to form groups of four to six individuals in the non-breeding season, in contrast to P. palmarum occurring singly or in pairs. Phaenicophilus poliocephalus is also smaller than adult P. palmarum for seven of 11 size-related features. We assessed the degree of gene flow across the narrow hybrid zone we documented and concluded, based on morphological variance analysis, that there was little introgression. The resemblance of P. poliocephalus to juvenile P. palmarum in general morphology and behavior, their smaller body size, and the increased tendency to form groups is consistent with a paedomorphic derivation of P. poliocephalus from P. palmarum.
URL:http://www.jstor.org/stable/1369326
Short Title:The Condor
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith