As regular CFZ-watchers will know, for some time Corinna has been doing a column for Animals & Men and a regular segment on On The Track... particularly about out-of-place birds and rare vagrants. There seem to be more and more bird stories from all over the world hitting the news these days so, to make room for them all - and to give them all equal and worthy coverage - she has set up this new blog to cover all things feathery and Fortean.

Thursday, 3 May 2018

Feather replacement or parental care? Migratory birds desert their offspring to molt

When parental care and the annual molt overlap in time, a migratory songbird often chooses single-parent desertion

Date:  April 19, 2018
Source:  American Ornithological Society Publications Office

A new study shows that when feather replacement and parental care overlap in time, migratory songbirds make a striking trade-off; they desert their offspring, leaving their mates to provide all remaining parental care.

This radical solution to conflict between parental care and the annual molt provides "a nice illustration of the complex lives that migratory songbirds lead," says Ron Mumme, the study's author and Professor of Biology at Allegheny College in northwestern Pennsylvania. "They have to negotiate conflicting demands and make difficult trade-offs and compromises, just like we do."

Migratory songbirds that breed in North America confront serious issues with time management. After spending a relatively leisurely winter and early spring luxuriating in warm tropical climates, they migrate north for a brief but highly eventful summer in North America, during which they must complete three energetically demanding and time-consuming tasks: (1) they must build nests, lay eggs, and provide for their offspring until the young reach independence, (2) they must completely replace all the feathers in their plumage as part of the annual molt, and (3) they must prepare for the fall southward migration by eating prodigiously and storing the body fat that will fuel their long-distance flights.

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