Some Interesting Cormorant Facts

Double-crested Cormorant

Cormorants get a lot of bad press these days. The Ontario Government is proposing a hunting season which would allow each hunter to kill 14,000 a year.

In my youth, it was rare to see a cormorant and was always a highlight of trips that I took to Sault Saint Marie and points further north.

In the 1960’s, an insecticide called DDT was commonly used and it had the side effect of causing cormorants to lay eggs with shells as thin as tissue paper when hatched, IF they hatched. Chicks were born with crossed bills and other defects. By 1970, there were only 89 cormorants in the entire Great Lakes.

After 1972, DDT was banned and the Migratory Bird Treaty Act gave further protection to cormorants. By 2001, cormorant population in the Great Lakes increased to over 200,000.

Double-crested Cormorants

People are concerned with the number of fish that cormorants eat, the damage they do to trees in their colonies and the fact that they terrorize gulls and terns trying to nest in the same areas.

Double-crested Cormorants in the Great Lakes region eat primarily introduced fish species of Round Goby and Alewife. 

Double-crested cormorant

In the Southern Hemisphere, cormorants are usually called “shags” and many species show lots of white:

Blue-eyed Shag

In Antarctica, cormorants sometimes breed in the same colonies as penguins and I was fortunate to see many while working as a naturalist there.

Some Gentoo Penguins nest with Shags
Blue-eyed Shags at the nest
Blue-eyed Shags and Gentoos
Blue-eyed Shag colony

While reading The Wonderful Mr Willughby (Bloomsbury Publishing 2018), the biography of a 17th-century naturalist, I came across this account of the use of cormorants for fishing.

In Strasbourg, France, we met a man who had a tame cormorant – a scarce bird on the Rhine – that was ‘tied to a string, who catch’d the fishes himself that he eats’.

Captive cormorants were ‘hood-winked’ (had a hood placed over their eyes) so that they ‘be not frightened’. ‘When the keepers come to the rivers, they take off their hoods, and having tied a leather thong round the lower parts or their necks that they may not swallow down the fish that they catch, they throw them into the river. 

Once the cormorants had caught five or six fish the birds are called to their keeper, and ‘little by little, one after another they vomit up all their fish a little bruised with the nip they gave them’

Double-crested Cormorant

“James 1 of England employed a keeper of cormorants in the early 1600s and enjoyed watching the captive birds fishing. So popular was this aquatic form of falconry that the king had birds imported both from the Isle of Man and Reedham in Norfolk, but also from Sevenhuis in the Netherlands where he ordered “yearly two ships full’. The cormorant fishing tradition was continued by Charles ll, who instructed his servant Richard Edes to ‘keepe and breede three cormorants for our recreation’. (“The Wonderful Mr Willughby” pg 100)

Double-crested Cormorant

Miles Hearn

1 thought on “Some Interesting Cormorant Facts

  1. George

    Double-crested Cormorants in the Great Lakes region eat primarily introduced fish species of Round Goby and Alewife. The proposal to make this bird a “game bird” is a political sop to the OFAH. It’s not scientific wildlife management.


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