• Imprinting. When a bird hatches, it does not know what its mother looks like. As a result, it usually gets attached to the character it first sees and recognizes as moving. Most often, such a character is its own mother, but sometimes it can even be a human. 

• Nest evasion. Young waterfowl leave their nest soon after hatching. This is why they are called nest-evasive birds. In contrasts, the young of some other bird species, such as those of the great tit, hatch in a less developed state, and stay in their nests for a couple of weeks after hatching. 

• Molting. Birds change their feathers regularly. By molting their feathers, their plumage and down stay in good condition. During the molting period, the bird is unable to fly for a couple of weeks, as their wing feathers are yet undeveloped. During this time, the birds often stay hidden in shrubs and other foliage.

The young goldeneyes have left their nest at a young age and imprinted themselves to their mother.