Evolution of winter molting strategies in European and North American migratory passerines. Issue 19 (1st September 2021)

• Record Type: Journal Article
• Authors: Pageau, Claudie; Sonnleitner, Jared; Tonra, Christopher M.; Shaikh, Mateen; Reudink, Matthew W.
• Is Part Of: Ecology and evolution. Volume 11:Issue 19(2021)
• Page Start: 13247
• Page End: 13258
• Publication Date: 2021-09-01
• Subjects: molt -- Nearctic -- Passeriformes -- phylogenetic analysis -- Western Palearctic; Ecology -- Periodicals; Evolution -- Periodicals; 577.05
• DOI: 10.1002/ece3.8047
• Languages: English
• ISSNs: 2045-7758

Abstract

Abstract: Molt is critical for birds as it replaces damaged feathers and worn plumage, enhancing flight performance, thermoregulation, and communication. In passerines, molt generally occurs on the breeding grounds during the postbreeding period once a year. However, some species of migrant passerines that breed in the Nearctic and Western Palearctic regions have evolved different molting strategies that involve molting on the overwintering grounds. Some species forego molt on the breeding grounds and instead complete their prebasic molt on the overwintering grounds. Other species molt some or all feathers a second time (prealternate molt) during the overwintering period. Using phylogenetic analyses, we explored the potential drivers of the evolution of winter molts in Nearctic and Western Palearctic breeding passerines. Our results indicate an association between longer photoperiods and the presence of prebasic and prealternate molts on the overwintering grounds for both Nearctic and Western Palearctic species. We also found a relationship between prealternate molt and generalist and water habitats for Western Palearctic species. Finally, the complete prealternate molt in Western Palearctic passerines was linked to longer days on the overwintering grounds and longer migration distance. Longer days may favor the evolution of winter prebasic molt by increasing the time window when birds can absorb essential nutrients for molt. Alternatively, for birds undertaking a prealternate molt at the end of the overwintering period, longer days may increase exposure to feather‐degrading ultra‐violet radiation, necessitating the replacement of feathers. Our study underlines the importance of the overwintering grounds in the critical process of molt for many passerines that breed in the Nearctic and Western Palearctic regions. Abstract : Our study explored the potential drivers of the evolution of winter molts in Nearctic and Western Palearctic breeding passerines. Using phylogenic analysis, we tested whether photoperiod, migration distance, NDVI of the breeding and overwintering grounds, habitat, and diet were associated with species undergoing a winter prebasic molt or a prealternate molt. Our study suggests that the evolution of winter molt strategies in Nearctic and Western Palearctic migratory passerines was likely driven by multiple factors, but photoperiod, migration distance, and overwintering ground conditions are particularly important.