Uncovered by retreating glaciers only about 150 years ago, South Marble Island in Glacier Bay is home to thousands of seabirds. Approaching the island we hear the cries of black-legged kittiwakes, nesting on the sheer cliff faces, and the calls of glaucous-winged gulls, nesting on the grassy slopes above. An adult bald eagle lands on the slope, and is mobbed by gulls, trying to prevent it from stealing their eggs. As many as seven eagles have been seen feeding on gull eggs on this island at one time, but the gulls continue to lay more, and all seem to successfully hatch two chicks, regardless of how many eggs are taken by the eagles. Another breeding bird on the island is the tufted puffin, one of the more spectacular birds on the northwest coast, and certainly a highlight of the trip. Nesting underground in burrows, they are easiest to spot sitting on the water or flying to and from the island, their bright orange bill, white face, and cream-colored "tufts" of feathers, seen only during the breeding season, contrasting with the solid black body. This is the largest of the puffins, weighing just over a pound, larger than their Atlantic cousins or the horned puffin, which also breeds here. Also known as "sea parrots", today we saw several small groups around the island. The vegetation on the island changes over time, "recovering" after the retreat of the glaciers, and more of the island is covered by trees. Puffins prefer treeless islands, so they may move further north in the bay, seeking new nesting sites.