Sunday, July 25, 2010

Nature Journal: That sinking feeling

Juvenile Pied-billed Grebe, Fernhill Wetlands, Forest Grove, Oregon on 13 July 2010 by Greg Gillson.

 

Two weeks ago I observed this juvenile Pied-billed Grebe at the local wetlands. To submerge, grebes either lunge forward and dive head-first, or simply sink. This bird used this latter method.

It actually happens quite quickly. The bird starts submerging at the breast, then the body goes under, and finally the head. Here are two submerging sequences.



























































Here's another set...





























4 comments:

  1. Wow that's cool.. I don't think I've ever seen them just sink!

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  2. Greg,

    Here is a link to a video of a grebe sinking I captured and posted on Flickr:

    http://www.flickr.com/photos/12567713@N00/3565619816/

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  3. Fascinating. I'll have to start paying more attention to how birds go under water.

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  4. Hi Greg.
    I was browsing through Cornell's Handbook of Bird Biology and came across this passage:
    Pied-billed Grebe Sinking:
    When mildly alarmed, the Pied-billed Grebe may squeeze air from its feathers and air sacs, decreasing its buoyancy and thus slowly sinking straight down into the water. It may submerge to various degrees, sometimes remaining completely underwater, sometimes leaving the neck and body partly visible, and sometimes leaving just the eyes and nostrils above the surface, to check for danger.
    It reminded me of your post and thought you would find it interesting.

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