Sunday, September 16, 2018

Great Cormorant

The great cormorant (Phalacrocorax carbo) has a number of subspecies. The nominate subspecies (P. c. carbo) is found in the western Atlantic along the eastern seaboard of North America, although it only breeds in the maritime provinces of Canada (New Brunswick, Nova Scotia and Prince Edward Island). The nominate subspecies is the largest, about 10% larger than the smallest subspecies. The largest great cormorants in the world are found on Prince Edward Island. 
A great cormorant.
The Australian subspecies is known as the black cormorant or black shag in New Zealand (P. c. novaehollandiea), the Sub-Saharan Africa subspecies is known as the white-breasted cormorant, (P. c. lucidus), and there are subspecies in Japan (P. c. hanedae), northwestern Africa (P. c. maroccanus), and western Europe to Asia (P. c. sinensis).   
Two great cormorants (back) and a double crested cormorant (front).
On our boat trip out to the bird islands off Cape Breton, outside Sydney, Nova Scotia, we were occasionally alerted to the presence of great cormorants among the hundreds of double crested cormorants we saw everywhere. From that I got the impression that the great cormorant was quite rare, particularly because we were told that these islands had 11% of the population of great cormorants. As I read and look back on it, they must have 11% of the breeding population of the subspecies carbo. 

A close-up of the beautiful wing feathers.
A close-up of the head.
It is only through reviewing my photos, taken with a long telephoto lense, that I'm really seeing the great cormorants now. Out of hundreds of double crested cormorants we saw, we probably saw about ten total great cormorants. Our boat captains pointed them out on the rocks when they would see them, I would take photos of the area, and now I'm picking them out. Now that I've done that, I think I could go again and readily pick them out. 

The great cormorant is larger and bulkier than the double crested cormorant, has less yellow on the bill and throat (in fact the double crested cormorant throat and bill color is more orange-ish) and the breeding great cormorant has a white patch on the bill and on the flanks (although I'm not really seeing the flank white patches on the great cormorants we saw). 
Double crested cormorants and one great cormorant (at the far right end). 
The photo above is cropped to isolate one of each. The differences are quite obvious. 

1 comment:

  1. The close-up of the wing feathers is wonderful. Such artistry exists in nature that we never really take time to examine. You do a good job of that.