Double-crested Cormorant, Phalacrocorax auritus
The Double-crested Cormorant (Phalacrocorax auritus) is a member of the cormorant family of seabirds. It occurs along inland waterways as well as in coastal areas, and is widely distributed across North America, from the Aleutian Islands in Alaska down to Florida and Mexico. Measuring 70–90 cm (28–35 in) in length, it is an all-black bird which gains a small double crest of black and white feathers in breeding season. It has a bare patch of orange-yellow facial skin. Five subspecies are recognized.
They are found near rivers, lakes and along the coastline. It mainly eats fish and hunts by swimming and diving. Its feathers, like those of all cormorants, are not waterproof and it must spend time drying them out after spending time in the water. This is actually an advantage, in that it makes the cormorants less buoyant, and therefore easier for them to dive for the fish that they eat.
Cormorants regurgitate pellets containing undigested parts of their meals such as bones. These pellets can be dissected by biologists in order to discover what they ate. Once threatened by use of DDT, the numbers of this bird have increased markedly in recent years.
There are few birds as controversial as cormorants, especially here in the Great Lakes region. Fishermen, both commercial and sport fishermen believe that cormorants are wiping out the populations of fish in the region, however, that has never been proven. There is also much concern about the devastation that large flocks of nesting cormorants can have on vegetation. Accumulated fecal matter below nests can kill the nest trees. When this happens, the cormorants may move to a new area or they may simply shift to nesting on the ground.
Here’s a little blurb from Wikipedia on those subjects:
“The Double-crested Cormorant’s numbers decreased in the 1960s due to the effects of DDT. Colonies have also been persecuted from time to time in areas where they are thought to compete with human fishing.
Recently the population of Double-crested Cormorants has increased. Some studies have concluded that the recovery was allowed by the decrease of contaminants, particularly the discontinued use of DDT. The population may have also increased because of aquaculture ponds in its southern wintering grounds. The ponds favor good over-winter survival and growth.
For populations nesting in the Great Lakes region, it is believed that the colonization of the lakes by the non-native alewife (a small prey fish) has provided optimal feeding conditions and hence good breeding success. Double-crested cormorants eat other species of fish besides alewives and have been implicated in the decline of some sport-fish populations in the Great Lakes and other areas. Scientists are not in agreement about the exact extent of the role of cormorants in these declines, but some believe that Double-crested Cormorants may be a factor for some populations and in some locations.
In light of this belief, and because of calls for action by the public, the United States Fish and Wildlife Service (the U.S. Federal government agency charged with their protection) has recently extended control options to some other government entities. This includes culling of populations and measures to thwart reproduction, in an effort to control their growing numbers.
The U.S. Fish and Wildlife Service retains oversight and the control measures are not extended to the general public (no hunting season). Many government agencies at different levels in both the U.S. and Canada continue to wrestle with how best to respond to the situation.
In May 2008, the Canadian government reduced significantly the number of nests of the birds on Middle Island, a small island in Lake Erie and part of Point Pelee National Park. This is an attempt to keep the small island in balance and preserve its vegetation but opponents to the plan have pointed out that it is based on faulty information, provided in part by anglers who view cormorants as competitors.”
I have personally seen what large flocks of cormorants nesting on small islands in the Great Lakes have done to the vegetation on those islands, they are barren of any greenery what so ever. Masses of cormorant guano left behind makes visiting these islands a rather unpleasant experience these days. That being said, I still like cormorants, and I doubt that they have any significant impact on the sport fish populations.
However, I threw that in for those people who believe that only mankind is responsible for any environmental damage. The truth is, every living species impacts the environment to some degree, man just more so than others.
On to the photos.
This is number 18 in my photo life list, only 332 to go!
That’s it for this one, thanks for stopping by!