Double-crested cormorant - what strange feather patterns

Double crested cormorant drying itself in Lloydminster, Alberta

The crests of a double-crested cormorant only appear during breeding season.  They appear on both breeding males and females.  The feathers can be white or black.  The white-crested variety tends to be from Alaska.  There is a good photo on this web page if you want to see the "crests".  Kudos to the photographer who took them.  I have never gotten that close to these magnificent birds.

I have gotten some good images of neotropic cormorants and little pied cormorants from Texas and Australia.  See the image below.  Also, New Zealand has a group of cormorant-like birds called shags.  The issue with them as a rule is that they are often in deep waters and rarely on land.  They are difficult to approach without startling them.  

Left:  Little pied cormorant (Australia)  Right:  Neotropic cormorant (Texas)

What I have always liked is the bold feather patterns that you can see on the birds' backs and wings.  I have enlarged the neotropic's feathers to show you what I mean.  There is an enlargement below.

Feather definition on neotropical cormorant

Double-crested cormorants have quite a wide range that covers much of North America, although their breeding range is in the central US/southern Canada.  Neotropic cormorants range from the far southern US all the way down to the far reaches of South America.  The interesting part in this is that their ranges overlap to some extent.  Where they overlap, interbreeding has been observed.  Viable young are produced which have characteristics between the two species.  I imagine the offspring are infertile, similar to mules which are the offspring between a horse and donkey.

Cormorants don't dive from the air the way osprey and eagles do.  They float on the surface like pelicans, but there the difference ends.  Cormorants dive, up to 25 feet beneath the surface, to approach fish and then quickly strike.  They will consume smaller prey underwater but will surface to eat larger items.  Not only do they eat fish, they also eat crustaceans (crabs, shrimp, etc.) and amphibians.

They are remarkable birds and worth watching, especially when they are actively fishing.

Thanks for reading.     www.ericspix.com