Hooded warbler males ditch nestlings to molt

[Cara J]

Hooded warbler (Setophaga citrina) moms must do double duty when the fathers tend to their feathers rather than their chicks. When nesting male hooded warblers replace their plumage in the late summer, a new study from Pennsylvania found, they commonly vanish to molt, leaving the females to rear their nestlings. Like other North American warbler species, as the breeding season nears its end, the hooded warbler loses its wing feathers and tail feathers, which it flicks open to reveal white tail spots that help startle hidden insect prey. Over the month-long molt, birds can’t fly, let alone fulfill their parental responsibilities. The males “desert the young, switch into molt and let their mate do the rest of parental care,” said Ronald Mumme, author of the paper published in The Auk: Ornithological Advances. A biology professor at Allegheny College, Mumme went searching for hooded warblers towards the close of nesting season every August from 2013 to 2017 in the dense understories of northwest Pennsylvania. He used call playbacks to attract 62 molting individuals into mist nets and locate their fledglings to determine if they were still caring for them. He discovered that nearly 70 percent of the birds — almost always [...]

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