One of the most evocative sounds of autumn is the calling of geese as they fly high overhead on a misty morning.
Geese tend to navigate using landmarks and in such conditions can become disorientated and often fly in circles above the mist until they regain their bearings.
In such conditions, or even on a clear day when they are too high to see properly, the best way to identify which species they are is by listening to their calls.
In the central Borders, the most frequent species are pinkfoot and greylag, which both arrive in huge numbers.
The greylags, which are the forebears of most of our farm geese, are distinguished by their “hooonk hooonk” calls, while the smaller pinkfeet give off a “wink wink” sound while in flight. Occasionally, barnacle geese fly over our area heading for the Solway and they have a more barking call.
On the ground, geese are collectively known as gaggles, but in flight they become skeins.
Most geese fly in a rough V formation, which boosts the efficiency and range of flying birds, particularly over long migratory routes. All the birds except the first fly in the upwash from the wingtip vortices of the bird ahead. The upwash assists each bird in supporting its own weight in flight, in the same way a glider can climb or maintain height indefinitely in rising air. In a V formation of 25 members, each bird can achieve a reduction of induced drag by up to 65 per cent and as a result increase their range by 71 per cent. The birds flying at the tips and at the front are rotated in a timely cyclical fashion to spread flight fatigue equally among the flock members.
There are several good roosting sites in the Borders, such as Hule Moss on Greenlaw Moor and Westwater near West Linton, but you have to be there at dawn or dusk to see them before they move off or return from their daytime feeding grounds.
This verse from a Bonchester Bridge reader reflects the magic of the annual goose invasion to our area.