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Folk, M.J., S.A. Nesbitt, J.M. Parker, M.G. Spalding, S.B. Baynes, and K.L. Candelora. Feather molt of nonmigratory whooping cranes in Florida. In: Folk, MJ and SA Nesbitt, eds. 2008. Proceedings of the Tenth North American Crane Workshop, Feb. 7-10, 2006, Zacatecas City, Zacatecas, Mexico: North American Crane Working Group. pp. 128-132.
Molt patterns of wild whooping cranes (Grus americana) are largely unknown, and what knowledge we have has been based on scant data. We documented patterns of feather molt in nonmigratory whooping cranes in Florida during 1993-2005. All birds replaced flight feathers (remiges) in a synchronous (simultaneous) manner and spent time flightless. It took 38-46 days (mean = 44 days, n = 8) for feathers to regrow and birds to regain flight ability. When flightless due to remigial molt, cranes became more secretive and spent more time in wetlands during feather regrowth. Most (70%) whooping cranes first molted their remiges at 3 years of age, 20% at 2 years of age, and 10% at 4 years of age. Birds never molted their flight feathers in consecutive years; instead they usually skipped 1 or 2 years between molts. Sets of flight feathers lasted 2-4 years (mean 2.5 years, n = 41). The remigial molt was seasonal; flight feathers were shed during 10 April-23 June, and contour plumage was molted later in the year (24 June-23 October). For 1-2 months in the summer prior to contour-plumage molt, whooping cranes took on a dingy gray appearance, but they appeared snowy white in autumn after the contour-feather molt.