Redwings and Fieldfares on the move (Focus - Nov)

With the abundance of fruits, seeds, and berries in the countryside this autumn, the migrant birds which visit us during the colder months should be in for a feast. This may make them less reliant on our bird tables. Thrush species, especially the redwing and fieldfare will particularly favour the hawthorn and holly berries which glow red along the hedgerows and through the woods. Only when they have exhausted all that supply will they move onto the open fields to look for food there. These birds will have travelled large distances from their breeding grounds to wintering areas; other species make much shorter journeys. Solitary birds, small groups, or whole flocks may arrive in an area overnight and then just as quickly move on.

By keeping an eye on the skies for a while on a regular basis it is possible to pick out those movements which are local – for instance short flights by cormorants between lakes in the area – and longer distance – for instance the continuous movement of swallows gradually working their way south at the end of summer.

Birders call watching such movements visible migration, or vismig for short. This contrasts with nocturnal migration or nocmig.

If you want to experience some nocmig for yourself at this time of year, keep your ears open when walking through the village after dark. Especially on nights with low cloud, one can often hear the calls of redwings passing over-head. Their distinctive, high-pitched “tseeep” call is easy to identify but they are by no means the only species to migrate at night. Many others, of which we may be blissfully unaware, will pass through under cover of darkness. Increasingly, recording devices are being employed, especially at coastal bird observatories, to monitor birdcalls through the hours of darkness. Then, with the help of the ever-improving bird call ID applications such as Merlin, it is possible to pick out which species have been passing over while we are asleep. This is telling us more about bird movements than we could previously determine from daylight observation and bird ringing.

Abrupt and significant changes in weather or food supply can prompt major movements of birds. It is always worth looking, listening, and considering where the birds around us have come from and are going.

​Andrew Graham