Forster's Tern, Sterna forsteri
These entertaining and supremely photogenic birds summer in the Bay Area, with nesting colonies all along San Francisco Bay. I never get tired of photographing them, and I have many more pictures that can be seen here.
Above, an adult in non-breeding plumage; Forster's Terns molt into this plumage in late summer and fall, before they migrate, and every year a few of them stay over through the winter in the Bay Area.
Above, an adult Forster's Tern in non-breeding plumage in front, and an immature bird, also in non-breeding plumage, in the rear. The adult has pure white surrounding the black eye patch on the head, while the nape and and crown of the immature bird are gray; both have the black bill of non-breeding Forster's. The much larger adult Royal Tern in the middle is also in non-breeding plumage in March; note the white forehead.
Above, a juvenile bird, fully fledged in mid-summer.
Like other terns, Forster's are plunge-feeders, diving to catch the fish that is their main food. Above, soaring; below, diving...
... and below, flying away after capturing a fish.
Above, two Forster's battling in mid-air over fishing rights; below, a male
and female in their courting flight together.
Above, more courting, the male presenting a fish to the female; below, the courting was successful, and the pair mated.
Above, one adult of a pair flies in as the other adult guards two recently hatched chicks, their patterned down providing camouflage; below, a month later, the two young have survived to fledge, and one of them flies in to join its sibling and a parent on the same island.