When a brown booby shows up in the northeastern U.S. it’s usually late in the year (August to December) and the bird is usually quite brown.  That’s because juvenile birds like this one are more prone to wandering from their tropical ocean homes than are their parents.

Having never seen a brown booby (Sula leucogaster) until this week at St. John, USVI my exposure was limited to a few photos of juvenile birds from Pennsylvania rare bird alerts.  For years I assumed that brown boobies were 100% brown.  Not!

Adults are crisp brown-and-white and even have white faces that acquire color in the breeding season.

Here’s a typical adult brown booby.  Quite a different-looking bird!

Since I’m used to seabirds in Maine I think it’s very cool that brown boobies so closely resemble northern gannets (Morus bassanus) in size, shape, and plunge-dive feeding strategy.

Fortunately they’re brown enough that you don’t misidentify them as gannets when you see them on the northern ocean.

Note: Brown boobies are very common tropical ocean birds but their population is declining in the Caribbean because of encroachment and invasive mammals on their nesting islands.  They made the State Of The Birds Watch List in 2014 because they’ve declined so much.

(brown booby photos from Wikimedia Commons. Click on the images to see the originals.  Northern gannet photo by Chuck Tague)