Cormorant Surveys
 
 
 
2019
The double-crested cormorant (Phalacrocorax auritus) is a member of the cormorant family of seabirds. Its habitat is near rivers and lakes 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 7090 cm (2835 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. 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. Once threatened by the use of DDT, the numbers of this bird have increased markedly in recent years (WikipediA).
 
When large numbers of cormorants congregate in a roosting or nesting area, their droppings can kill trees and other vegetation. They also compete with loons and other fish-feeding birds for food.

Cormorants have been using White Lake for many years. However, their numbers have always remained small. In recent years, we have noticed that the White Lake population of cormorants was increasing. As part of our water quality monitoring program, we decided to start monitoring cormorant numbers on White Lake. Every two weeks we patrol and sample 9 sites in all parts of the lake. Samples for total phosphorus are collected as are plankton samples, water temperature and secchi depth. During this two-hour period, we collect data on the location and numbers of cormorants at 4 specific sites, where they have been observed to roost. We do not know the location of the nesting sites at this time. Sites 1,2 and 4 (see map) are exposed rocks where local gulls also roost. Sites 2 and 4 are submerged until late summer whereas site 1 is available during the entire summer. Site 3 is a small islet on the north end of the Stanley Island group. Cormorants were observed there roosting in the tall pines as well as on the rocks along the shoreline.
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2020