Category Archives: Terns

Terns: Royal Tern

Starting in early July, I make it a point to visit the Basket Island causeway a couple of times per week. This southern Maine spot is a premier location for observing summer shorebirds, gulls, and terns. I often bird the causeway 1-2 hours after low tide, when the rising waters concentrate a variety of birds onto shrinking sandbars.

Photo of Royal Tern

During a visit on July 2nd, I'd already photographed my first Whimbrel of the year, and was watching a small group of Roseate Terns, when I noticed a much larger tern alone in the distance. Caspian? No, this bird lacked a full black cap, and had an orange, not red bill. It'd been almost two full years since my first and only sighting of a Royal Tern at this same location, but finally I was looking at another.

Photo of Royal Tern

Unfortunately, almost as soon as I noticed the tern, some beach-goers approached the bird from the other direction. Before they pushed the bird, I moved quickly to capture the photos you see here. Moments later, the walkers got too close and the Royal Tern took flight, flying past me and out over the water where I lost him/her in the bright morning sun.

Photo of Royal Tern

I suspect this won't be my last Royal Tern sighting. I just hope the next one doesn't take another two years. You can bet I'll be visiting the Basket Island causeway a few more times this summer to increase my odds.

To learn more about Royal Terns, and hear samples of their calls, visit All About Birds. And if you'd like to go birding with me, keep an eye on my upcoming walks or consider hiring me for a custom birding workshop.

Terns: Caspian Tern

When I arrived at the Basket Island causeway (at Hills Beach in Biddeford, ME) one afternoon last month, I scanned the rising waters and the shrinking sand bars, noting the usual assortment of late-August birds. In late summer, on the rising tide, the causeway often hosts flocks of gulls, sandpipers, plovers, and terns. And sometimes, sifting through the masses reveals unusual or rare birds.

Photo of Caspian Tern with Herring and Great Black-backed Gull

Tern numbers were low that afternoon, but when this black-capped, red-billed Caspian Tern landed to join the mixed flock of gulls on the causeway, I penciled in one more bird code (CATE) to my observation notebook. Caspian Terns are rare visitors to Maine, typically seen only during spring/fall migration, and this was my first (and only) sighting in 2015. (I photographed the following duo in May of 2014 at Goose Rocks Beach.)

Photo of Caspian Terns with Ring-billed Gull

To balance the scales with a single Caspian TernĀ (1.4 lb) it would take five or six Common Terns (4.2 oz/ea) or almost fifteen Least Terns (1.5 oz/ea)*. As you might guess, they are the world's largest tern. Royal Terns (weighing about 1 lb) are the only other species likely to be mistaken for a Caspian. The two look most similar in spring, but by mid-summer, Royals lose their full black cap (see All About Birds for photos), making them easy to tell apart.

Photo of Caspian Tern in flight

*Weight estimates from David Allen Sibley's The Sibley Guide to Birds (2014).