The double-crested cormorant is a dark waterbird that is found through out North America. They primarily breed in colonies on lakes and larger ponds in the the central portion of the continent, although their are also some colonies on the east and west coast and Florida. The cormorants that breed in the central portion of the continent migrate to coastal regions of the East, West and Gulf Coasts during the winter. Doubkle-crested cormorants get their name from dual black and white crests that are visible on their heads during the breeding season.
Like other cormorant species the double-crested cormorant does not produce as much preen oils as other birds. These oils help to provide birds such as ducks with a waterproof coating for their feathers. Having less preen oils the cormorant feathers can get soaked as they are diving for fish, which is their main type of food. Having their feathers soaked actually help them under the water because the added weight helps to compensate for the buoyancy of their light bodies. After they are done diving they can often be seen perched in the sun with their wings out stretched drying their feathers.
In the 1960's the double-crested cormorant populations plummeted because of DDT. DDT was an insecticide that affected the production of egg shells in many different species of birds, including the cormorants. Most of the eggs would break while the birds were trying to incubate them because of their thin shells. DDT was banned in 1972 and like other species affected by DDT the cormorants have made a complete recovery.
8 comments:
Very enlightening. I had an opportunity to paddle out to a nesting ground, a small island, yesterday and wander. Their nests were numerous and really cool. There were still lots of them on this island, but they certainly don't let you get too close. However, upon leaving the island, I let the current take me around a little point and they didn't know I was there, so I got up close. My camera was packed away, though, darn.
Wonderful photos and very interesting to see them in flight. Great post and as always very informative, thank you!
crested so nice, they crested it twice.
ROG, ABC Wednesday team
Interesting looking bird, great in flight shots!
Now that's a Decent take off eh :)
PhenoMenon, ABCW Team
Great post, very informative, great photos of bird in flight and good to know they ave recovered now.
Thank you for this interesting post. Every time I visit you I learn something new!
Have a great week!
Wil, ABCW Team.
Oh My Goodness, these are aboslutely glorious captures...very well done!!!
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