Answer to Pop Birdquiz 13: New Jersey, March

 

DELAWARE BIRDS
So here we have four apparently very large and mostly black birds perched on top of some man-made structure. For me, that combination typically would trigger brain cells in the part of my brain that recognizes vultures. Although they look big enough to be vultures, the major problems are that the plumage on the head has a combination of black, gray, and white that is not vulture-like, and the bills on these birds are also not vulture-like, being much more elongated. A closer look at the elongated bill reveals that the upper mandible curls and hooks over the lower one. That bill shape points directly towards the cormorants. Here in NJ the default cormorant is the Double-Crested Cormorant, but during the winter Great Cormorants are seen near the ocean and other large bodies of water. (Neotropic Cormorant is a rare sighting in NJ) To distinguish these species in immature birds, we typically would determine whether the bird has a pale breast (Double-crested) or a white belly (Great Cormorant). Unfortunately, despite having four birds here, none is facing the viewer. Adult Double-crested Cormorants are completely orange around the throat at the base of the bill, while Great Cormorant has a white throat patch and sports a white ‘hip patch’ when in breeding plumage. Two of these birds have a clear white throat patch, and the other two have clear hip patches. These are four breeding plumaged Great Cormorants roosting over the lower Delaware River, soon to depart for their breeding grounds.

A closer view shows the details of the breeding plumage in this species and the tip of the bill.
Great Cormorant

 Posted by at 3:17 PM