It's a stirring sight on a bright spring day. However, these birds famously form large flocks for migration. Flocked migrants are the most conspicuous of migrating birds and are the most familiar to us. Additionally, flock sizes are shown. Cormorants eat only what they need to survive, including meeting the energetic costs of breeding and migration, or to feed their chicks while they are in the nest. The yellow orange, unfeathered throat pouch of the double-crested cormorant distinguishes it from similar species. Double-crested cormorants are long-necked black birds often seen sitting on piers and rocks in an upright position with wings open in a spread eagle posture. They are also easiest to watch because they are generally daytime migrants. The Double-crested (which rarely looks noticeably crested in the field) is the most generally distributed cormorant in North America, and the only one likely to be seen inland in most areas. Robins tend to flock south for warmer weather and more food availability in winter. On the other hand, cormorants do not breed in the area and are rare from late spring to late summer. ... Like all cormorants its dives for its food. The birds feed individually or in flocks, sometimes working together to increase their foraging efficiency. As a result of daily migration counts carried out in central North Rhine-Westphalia from mid-August to mid-November during 2001 and 2003, I describe migration patterns both throughout the autumn and within a day. Dark and swift, flocks of cormorants soar above Lake Ontario before hundreds of them finally dip down to the diamond-flecked water. Robins . They migrate in large flocks during autumn and early spring, but in winter they are present only on some ice-free water bodies. Each year, from mid-February to mid-April, between 400,000 and 600,000 sandhill cranes migrate to the central Platte River in Nebraska. Individuals occasionally migrate as far west as the Red Sea coast. Older reports suggest that it can stay submerged for up to 3 minutes, which is high for a cormorant and suggests that it would be capable of deep diving. However, there are also reports of foraging in flocks, and this is more usually seen in cormorants that feed in mid-water. Birds Migrating in Flocks or Alone Some species of birds are highly social during migration, moving in flocks that may stay together for the whole journey. Adult birds in breeding plumage have a crest on either side of the head. The birds congregate for feeding before they head further north to their subarctic nesting grounds. This dark, long-bodied diving bird floats low in the water with its thin neck and bill raised; perches upright near water with wings half-spread to dry.