The greylag goose (Anser anser) was once the only goose that bred in Great Britain, and the name could be a reference to it lagging behind when all the other species had migrated. It was from the greylag that the familiar white farmyard goose descended, and there is a hint of this in the cackles and in-flight honks that are produced by both types of goose.
The greylag is a large goose, at 30-35 inches (75-90 cms) in length. It is – unsurprisingly – brown/grey in colour, with the head and neck being paler than the body. The legs are pink and the heavy bill is pink or orange. The sexes are alike.
The natural breeding ground for greylag geese is wild Scotland, particularly the heather moors with their lochs and lochans. They will also inhabit sea lochs, which is unusual for geese.
Greylag geese pair up for life and they go through a re-enactment of their courtship dance should they be separated for any length of time and then get back together. This is a complicated ritual of calling and posturing.
Nests are built on the ground near water and are made from heather, grass or moss. The eggs hatch after about a month and the goslings take to the water within hours. They are ready to fly when about two months old. They stay in the family group until the following Spring.
(The photo is taken from a copyright-free source)