Canada Geese (Branta Canadensis Canadensis) are the most abundant wild geese and there are various subspecies that differ in voice, size, color intensity, proportion, posture, head, bill and neck shape, all are identifiable as Canada Geese (Branta Canadensis Canadensis) by their black head and neck, and white cheek patches that join beneath the chin. They feed in swallow water, where their long necks enable them to reach underwater vegetation. Canada Geese (Branta Canadensis Canadensis) are primarily herbivores, although they sometimes eat small insects and fish. Their diet includes a variety of green vegetation and aquatic plants, such as seaweeds. They also eats beans and grains such as wheat, rice, and corn when they are available. In urban areas, they are also known to pick food out of garbage bins. They are monogamous, and most couples stay together all of their lives. The female lays from 2–9 eggs with an average of five and both parents protect the nest while the eggs incubate, but the female spends more time at the nest than the male. Their nest is usually located in an elevated area near water such as streams, lakes, ponds and sometimes on a beaver lodge. Their eggs are laid in a shallow depression lined with plant material and down. They incubate for 28 days after laying. As the annual summer molt also takes place during the breeding season, the adults lose their flight feathers for 20–40 days, regaining flight at about the same time as their goslings start to fly. Both parents are assiduous in gosling care. As soon as the goslings hatch, they are immediately capable of walking, swimming and finding their own food (a diet similar to the adult geese). Parents are often seen leading their goslings in a line, usually with one adult at the front, and the other at the back. While protecting their goslings, parents often violently chase away nearby creatures, from small blackbirds to lone humans that approach, after warning them by giving off a hissing sound and will then attack with bites and slaps of the wings if the threat does not retreat or has seized a gosling. Canada Geese (Branta Canadensis Canadensis) are known for their seasonal migrations. Their autumn migration can be seen from September to the beginning of November. Canada Geese (Branta Canadensis Canadensis) fly in a distinctive V-shaped flight formation, with an altitude of 1 km (3,000 feet) for migration flight.