In Hudson and Bergen County, NJ, the most likely terns you’ll see are Common Terns (Sterna hirundo) or Forster’s Terns (Sterna forsteri). Smaller than seagulls, with long pointed wings and forked tails, terns fly gracefully. They’re also very vocal–I often hear terns’ “kerr-kerrr” and “keeearrrrr” sounds before I see them. They breed in colonies and are often seen in groups, though there’s lots of bickering over who gets the best hunting perch. Both Common and Forster’s Terns are considered to be medium-sized members of the tern family (Sternidae), but whenever I see them up close, I’m struck by how small they are.
I generally see Forster’s Terns along and near the Hackensack River and Common Terns along the shore in Jersey City and Bayonne, but of course there are exceptions. The Forster’s Terns in this gallery were photographed at DeKorte Park in Lyndhurst (many of those pictured are juveniles) and the Common Terns were at both Liberty State Park and on the Hudson River Waterfront Walkway in Bayonne (near the Bayonne Golf Course).
How does one tell these two types apart? The Forster’s Tern is a paler, more uniform gray and when it’s standing its tail is visibly longer than its wings. Both types have orange bills with black tips, but the Forster’s Tern’s bill is a paler orange and it has more of a black tip than the Common Tern. The Common Tern’s bill is a darker orange (almost red) and it has darker gray feathers on its back. It also has a black “wedge” on its outer wingtips, visible easily in flight and when its wings are folded. The two are much easier to tell apart in their winter plumage: The Forster’s Tern has a comma-shaped black spot over its eye and the Common Tern has black that wraps around the back of its head. Of course, they migrate, so the best time to see terns in non-breeding plumage is when they arrive in the spring or just before they fly south.
The Common Tern is considered to be of special concern as a breeding species in New Jersey due to habitat loss and loss of nesting areas to gull species.