ユウガアジサシ Thalasseus elegans

Long-billed tern of the Pacific coast, from the U.S. to Chile. Pale gray above with shaggy black cap in breeding plumage; nonbreeding birds develop white forehead. Best field mark is the slender orange bill with a slight droop. Strictly coastal; commonly found on beaches and estuaries. Similar to Royal Tern but smaller and slimmer with a thinner bill. Harsh grating calls similar to other terns.