Saturday, January 16, 2021

Double-crested Cormorant

Erika and I encountered this Double-crested Cormorant on 6 January 2021 at the Billy Frank Jr National Wildlife Refuge. Wing-Spreading is a common, but not universal, cormorant behavior. Cormorants do spread oil on their feathers, an action that water-proofs feathers in other birds. Cormorants, however, may make use of wet feathers, since that makes the birds less buoyant when they dive. Wet feathers, however, facilitate heat loss in the birds. Most ornithologists believe wing-spreading is a thermoregulatory behavior. Occasionally, wing-spreading is done in the rain, which would be an odd thing to do for a cold cormorant. The answer may be that this behavior simply contributes to feather maintenence (Dorr et al. 2020). The second photo is of a Galapagos Cormorant on 2 May 1976 showing the same behavior. Interestingly, this species is flightless.

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