A Brown-hooded Gull (Chroicocephalus maculipennis) and a Snowy-crowned Tern (Sterna trudeau), perched on some rocks along the Rio de la Plata in Montevideo, Uruguay. These birds were photographed from the Rambla República Argentina, between Dique Mauá and Playa Ramirez. Both birds are in basic plumage, which is to be expected, as this photograph was taken towards the end of the Uruguayan summer.

The Brown-hooded Gull is the larger, taller bird standing furthest away from the camera. Structurally, it is similar in size and shape to the Bonaparte's Gull of North America, which is one of its close relatives. It is a relatively small gull with a slight body and fairly short, dark reddish legs. Its head is proportional to the rest of its body, with a fairly small, delicate, and slightly drooping reddish bill and a long, gradually rising forehead that ends in a small peak towards the rear of the bird's head. Having already molted into basic plumage, this bird’s head and face are almost completely white, with just a small, dark auricular spot behind each eye. This auricular spot is all that remains of the dark brown head and face that it sported during the summer months.

The Snowy-crowned Tern is the smaller, shorter bird closest to the camera. It has the small, squat structure of an Arctic or Common Tern, with ridiculously small legs that seem as if they are about to collapse under the weight of the bird’s body. Although a number of small terns frequent Uruguay’s shoreline, this one can be identified by the odd, almost bulbous shape to its head; its long, slightly drooping bill; and the dark eyeline that recurves sharply behind each of its eyes. In basic plumage (seen here), this bird's bill is black, with a bright yellow tip, and its legs are dark red to black. In alternate plumage, its bill color becomes yellow, with a dark, vertical stripe near the tip, and its legs turn reddish. I am a bi t concerned about this bird's underparts, which should be grayish in all plumages. I do not seen this picture; however, this could very well have been caused by feather wear and bleaching from the sun.