On 16 August an immature and very cooperative, ABA Code-3, Brown Booby (Sula leucogaster) was spotted by Mary Richmond at the breakwater of Corporation Beach, Dennis, Massachusetts. A photograph of the bird can be viewed here.
This pantropical species is known to disperse northward after breeding and it is the nominate subspecies that occurs in the Caribbean and tropical Atlantic. They are strictly a marine species feeding primarily on inshore wasters where they capture squid, halfbeak, mullet, and anchovy, and depending less on fly-fish than other boobies (Handbook of the Birds of the World, Volume 1). They practice kleptoparasitism (especially on frigatebirds) a common trait in large fish-eating species (Smithsonian Field Guide to the Birds of North America, Floyd). Like other boobies they plunge-dive for prey items, flying low over the water while diving at an oblique angle. Underwater, they use their wings in short underwater pursuits of prey their but will also take prey from the surface.
Boobies have highly developed sizable air sacs, extensions of the bronchi that help to minimize the impact of crashing into the water. Their short legs with wide webbing on their feet help them in their pursuit of prey underwater. Because they need to fly on a daily basis, flight feathers are molted continuously thus avoiding periods of incapacity. Boobies lack brood patches, instead incubating eggs on their highly vasculated feet (Handbook of the Birds of the World).