14 September 2016

Yesterday’s blog about double-crested cormorants reminded me there other birds that spread their wings to dry, not fly.  Some of them aren’t even wet when they do it.

Cormorants’ feathers are wettable but a layer near the skin stays dry so they don’t get very cold.  This allows them to live in the North Atlantic and the Aleutians (see species list below) where they sometimes “dry” their wings in fog or rain.

Anhingas (Anhinga anhinga) aren’t so lucky.  When they go swimming they get soaked and have to get out of the water to warm up.  This limits their distribution to warm climate zones.

Turkey vultures (Cathartes aura) are often dry when they spread their wings because they’re doing it to warm up.  Overnight their body temperature drops so a good sunning is welcome in the morning.

So there’s more than one reason to spread your wings.  Read more about it here.

(photo of double-crested cormorants by Steve Gosser. Anhinga and turkey vulture photos from Wikimedia Commons. Click on the Wikimedia images to see the originals.)

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p.s. Cormorant species list:  In North America the genus Phalacrocorax (“sea raven”) has six members, though one is rare.

• Along the Pacific coast:
  • Brandt’s cormorant, Urile penicillatus
  • Red-faced cormorant, Urile urile  (This rare bird only occurs from Alaska to Russia, spanning the Aleutians.)
  • Pelagic cormorant, Urile pelagicus
• On the Atlantic coast:
  • Great cormorant or “black shag”, Phalacrocorax carbo (Occurs worldwide. In North America breeds only in Maine and Greenland.)
• In eastern North America and along the Atlantic coast:
  • Double-crested cormorant, Nannopterum auritum
• In the Gulf of Mexico region, the Caribbean and South America:
  • Neotropic cormorant, Nannopterum brasilianum