AVIS-IBIS

Birds of Indian Subcontinent

Plumage and Molt in Shorebirds Summering at Enewetak Atoll

Publication Type:Journal Article
Year of Publication:1977
Authors:Johnson, OW
Journal:The Auk
Volume:94
Issue:2
Date Published:1977
ISBN Number:00048038
Keywords:Arenaria interpres, Heteroscelus incanus, Marshall Islands, Numenius, Numenius arquata, Numenius phaeopus, Numenius tahitiensis, Pluvialis apricaria, Scolopacidae, Tringa incana
Abstract:Various features of plumage and molt were studied in Golden Plovers, Whimbrels, Bristle-thighed Curlews, Wandering Tattlers, and Ruddy Turnstones. Specimens collected during July 1973 at Enewetak Atoll, Marshall Islands, represent birds that had not migrated to the northern breeding grounds. Based upon several criteria (bursa of Fabricius, wear of remiges and rectrices, and the condition of body feathers) most specimens appeared to be first-year birds. The relative development of alternate plumage showed considerable individual variation, which presumably reflects physiological variability in the factors controlling prealternate molt in the late winter and spring. Many birds remain in nonbreeding plumage (exhibiting only a few alternate feathers), and essentially pass from one basic plumage to another while on the winter range. Plovers replace primaries, secondaries, and some tertials during the winter, and were undergoing a complete prebasic molt in July. Such a pattern varies considerably from molt chronology in postnuptial adults. Whimbrels and Bristle-thighed Curlews finish wing molt in the late spring to midsummer, and birds collected in July had not yet begun prebasic molt. Wandering Tattlers were molting juvenal remiges commencing with the 6th and progressing to the 10th primary. The molting sequence of primaries 1 through 5 was not entirely clear. Museum skins indicated that remige molt starts with the 1st primary in some specimens. The overall pattern awaits detailed study for clarification. No indications of prebasic molt were found in summering turnstones, hence subsequent timing of this molt may coincide with that of postnuptial adults. As no wing molt was occurring, first-year birds apparently retain their juvenal remiges until the prebasic II molt. In each species, summering birds showed considerable individual variability in ongoing rectrix molt. Also some specimens had replaced a few or all of these feathers during the preceding winter while others had not.
URL:http://www.jstor.org/stable/4085084
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