Royal Tern

Thalasseus maximus

Royal Tern

Royal tern, photographed at Spanish River Park, Boca Raton, Palm Beach County, in December 2017.

A bird with male pattern baldness. That's what comes to mind when we see the royal tern, Thalasseus maxium. And the image is actually more appropriate than you might first think.

For a short time during breeding season, adult royal terns sport a black "skull cap" that covers the top of the head. For most of the year, however, it recedes to the back and sides of the head, leaving the top white — and creating the male pattern baldness look. Of course, come next breeding season the full skull cap — the full black head — returns without the birds resorting to dyes, toupees or joining the feather club for terns.

Royal terns are shore birds, rarely straying far inland. They feed in the waters offshore and they breed on the beaches of islands.

In winter, they can be found on Florida's beaches and along the Gulf and Atlantic coasts as far north as North Carolina. A portion of the royal tern population spends the summer on the beaches of the Mid-Atlantic states and as far north as Massachusetts. Southern California is another wintering spot for western populations. They are found year-round in the Caribbean and in parts of Mexico, Central America and South America.

Royal terns along with another bird, sandwich terns, were common nesters in Florida until the late 19th century, then for some unknown reason, both stopped breeding in Florida. Both terns formed huge mixed nesting colonies. The first royal tern nests in the 20th century were found in Port St. Joe in Gulf County in 1951, according to the Florida Fish and Wildlife Conservation Commission. Nesting colonies since have been established in Tampa Bay and along Merritt Island and in other places in the state.

As noted above, for most of the year, royal terns have a white face and top of the head, with an unruly looking black rim on the sides and back. The bill is a bright orange, the eyes dark, the body white and wings a light gray with dark tips.

It is fairly large, with a body length of a foot-and-a-half or more and wingspan that can exceed four feet. Among terns, its size is exceeded only by the Caspian tern. Caspian terns are probably the closest in looks to royal terns, but the bill on the Caspian is thicker, slightly two-toned at the tip and more red to the royal's more orange.

Royal terns fly over water with their heads facing down, looking for fish or shrimp or some other seafood delight. When they spot a meal, they will plunge straight down, emerging with the catch and flying off to eat it.

Island beaches are favorite nesting spots for royal terns. They scrape out a hole, then poop on the sides, which acts as a kind of cement to reinforce the nest. Females lay one or two eggs, with both parents doing the incubating. According to the FWC, 90 percent of the nests in Florida have only one egg. The eggs hatch in four to five weeks, with the offspring joining a large gathering of royal tern chicks called a creche. A creche can number in the thousands, but the parents will find and feed only their own offspring.

Royal terns are able to fledge within four to five weeks, but will stay with their parents for as long as eight months and will migrate with them. They become sexually mature in four years.

This was another bird that once saw its population diminished substantially because of humans, in this case because the nests were raided for food. Although royal terns have bounced back, they're still vulnerable to loss of suitable nesting habitat and foraging grounds.

A quick taxonomic note: Royal terns were once known scientifically as Sterna maxima, and the name is still seen in some older references. Royal terns are members of Laridae, the gull and tern family.

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Published by Wild South Florida, PO Box 7241, Delray Beach, FL 33482.

Photographs by David Sedore. Photographs are property of the publishers and may not be used without permission.