what kind creatures are they?
A dabbling duck .
Mallard
The mallard () ("Anas platyrhynchos") is a dabbling duck that breeds throughout the temperate and subtropical Americas, Eurosiberia, and North Africa and has been introduced to New Zealand, Australia, Peru, Brazil, Uruguay, Argentina, Chile, Colombia, the Falkland Islands, and South Africa.
when does a male mallards head turn green During the final period of maturity leading up to adulthood (6–10 months of age).
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Mallard [SEP] Introduction
The mallard () ("Anas platyrhynchos") is a dabbling duck that breeds throughout the temperate and subtropical Americas, Eurosiberia, and North Africa and has been introduced to New Zealand, Australia, Peru, Brazil, Uruguay, Argentina, Chile, Colombia, the Falkland Islands, and South Africa. This duck belongs to the subfamily Anatinae of the waterfowl family Anatidae. The male birds (drakes) have a glossy green head and are grey on their wings and belly, while the females (hens or ducks) have mainly brown-speckled plumage. Both sexes have an area of white-bordered black or iridescent blue feathers called a speculum on their wings; males especially tend to have blue speculum feathers.