Greater crested tern
There are no global conservation concerns for this bird, which has a stable total population of more than 500,000 individuals. The breeding adult of the nominate subspecies T. bergii is 46–49 cm long, with a 125–130 cm wing-span. In winter, the upperparts plumage wears to a paler grey, and the crown of the head becomes white, merging the rear into a black...