送交者: apate 于 2005-1-09, 21:26:13:
回答: 今天头一次看见整齐的排成"人'字型飞的燕群 由 shine 于 2005-1-09, 18:21:28:
they were probably mallards (Anas platyrhynchos), a common kind of ducks with a glossy green head and neck. (also could be pintails, but they don't have shiny necks. cf. http://duckcentral.com/Pintail.470.0.html). swans, geese, and ducks belong to the same family; swans are bigger than geese, and geese bigger than ducks.
the shape of their flight is usually called the V formation. hhs and chqlz are about right.