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Monday
Sep172012

Ternapolooza!


One of the more intersting reports of this Autumn was of an Elegant Tern at Sandy Hook NRA. I was fortunate enough to see and photograph this bird, as well as a number of other tern species, there and elsewhere on the New Jersey coast.

 While the Elegant Tern most closely resembles our Royal and Caspian Terns, it was associating itself with Common, Forster's, and Black Terns as well as Black Skimmers.

A look at the images immediately above and below this note should help identifying these species at this time of year. The birds in the left image of the first row and the last image in the third row are Black Skimmers. These are unique terns in North America in that their lower mandibles are noticeably longer than their upper mandibles. As such, these birds are rarely misidentified.

A bit more difficult to separate are the Royal (third from the left image in the first row and the right image in the bottom row) and Caspian Terns (left image in the second and fourth rows). At this time of year, the Royal Tern has a prominent receding "hair" line giving it a white forehead that extends back behind its eyes. The Caspian Tern, on the other hand, always has black from the back of its head to the top of its bill. True, at this time of year, there are often some white feathers mixed in with the black ones, but they are relatively small in number. 

The issue many of us eastern birders where concerned with was how difficult it would be to separate the Elegant Tern from the Royal Tern. However, this turned out to be rather easy as the black on the back of the head of Royal does not extend down the back of its head while it does on the Elegant Tern. There is even less of an issue separating the Elegant from the Caspian as the latter has an essentially solid black cap.

The most difficult tern species to separate are Common (right image in the first row and next to the right image in the third row) and Forster's Terns (next to the right image in the second row and left image of the third row). However, at this time of year, they are relatively easier to tell apart. The Forster's Tern, at this time of year, has two black ear patches. Note that the back of the Forster's Tern's head is white. The Common Tern, on the other hand, has black ear patches that are connected with black behind its head. As such, only its forehead is white.

The last species present with New Jersey's first Elegant Tern was the Black Tern (next to the left image in the first and third rows). This is a small tern and is smudged with black on its head and upper surface.

There were three species that reasonably could have been seen but were not present: the Gull-billed, Least, and Sandwich Terns. The Gull-billed Tern (next to the left image in the last row) has a stubby (for a tern) all black bill. The Least is our smallest tern, has a yellow (sometimes yellowish) bill, and always has a white triangle above its bill. The Sandwich Tern is about the length of the Royal Tern, but has shorter legs. It also has a black bill tipped with yellow (mustard on this ham sandwich).

I hope this short note helps you identify the species of tern that occur in New Jersey.



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