You might be puzzled to see these geese flocks flying north or east early in the morning, how can it be that they are not going south? The reason is these birds are wintering or staging their migration in the Humber Estuary. What we are watching is their daily commute, in fact, their morning rush hour! Every night, the flocks gather to roost Read's Island and Whitton Island in the upper Humber estuary, where they are safe from disturbance and predation. At day rise, the birds fly to fields on Holderness or the wolds to feed, favouring fallow fields, or the spilt grain in those fields still to be planted, and also left-over potatoes! A similar movement happens towards Lincolnshire.
The Pink-footed geese population suffered strong declines in the 20th century, but it has been steadily increasing in the last couple of decades. The increase was followed by a renewed use of the Humber Estuary for wintering and also as a staging post on the way to Norfolk. UK coasts and estuaries now hold a sizeable amount of the total wintering population of this geese species, estimated to be about half a million birds.
With the constant daily movement, it is unavoidable that a few stragglers will separate from the flock. They call pitifully when trying to catch up. Many will eventually find the flock. Some others, which could mainly be young birds which haven't learned the route, may be disoriented and join a Greylag flock, as has happened several times in our local parks.
More information
A Humber Goose spectacular. RSPB Blog by Pete Short.