Restless spirits: bird changeover time is here. There is probably never a day when birds aren’t migrating, so finding the perfect time to write about bird migration is impossible, but mid to late October in Britain marks the big changeover when the last summer migrants depart, and most of the winter birds are arriving. The continuously changing bird gallery is what makes birdwatchers keep going to the same places; you never know what might turn up, sometimes a rare bird will pause briefly in your patch or may just pass through for a few moments never to be seen again. Our volunteer bird surveyor Roger Buisson was lucky enough to be doing a count at Westfield in late September when an osprey flew over, for example. One of the most obvious summer visitors to our farms and villages are the swallows, these familiar birds often nest on our buildings and like to feed on the flies attracted to livestock and their dung. These birds are more or less all gone by now; the last ones seen on CRT property were at Bere Marsh in the second week of October; I haven’t seen any around Lark Rise in Barton since I went away for a week at the end of September, though I did see some while I was in Scotland that week, my last ones were flying close to the M74 as we drove back into England on October 3rd. I like to keep in touch with migration by following some of the Bird Observatories which are situated at suitable watchpoints; the observers on Skokholm Island off the Pembrokeshire coast counted 42 swallows on October 20th but these were a notably large number for so late in the year. There is still time to spot one or two late breeding individuals and with milder winters, a very small number of swallows sometimes stay in sheltered spots. Have you spotted a swallow flying high? Grab a picture and send it to us! Replacing these summer visitors we get an influx of other species, most notably redwings and fieldfares, two types of thrush species which breed further north in Scandinavia and elsewhere in northern Europe. As their breeding grounds become ice- and snow-bound in winter they move south and west to milder climates, finding a wealth of berry-bearing hedges and worm-filled wet fields in Britain perfect to keep them fed through these harsh months. Our farmed landscape is ideal for these birds, particularly where hedges are left untrimmed, and fields are not chemically dosed. My first redwings in Cambridgeshire were on the 10th of October, almost a week before they were first seen in Dorset. This is fairly typical, as the birds arrive across the north sea coast and settle in eastern Britain first, moving on south and west as the weeks progress. Following the adventures of the North Ronaldsay (Orkney) bird observatory, they saw redwings and fieldfares a couple of weeks earlier still. When they are all in, redwings can be one of the commonest birds in Britain in winter, flocks of over 100 are not uncommon. They haven’t arrived in Herefordshire yet but when they get there, they stay in larger numbers as the orchards provide abundant windfall apples and the mild wet fields are so rich in earthworms. The pattern of arrival across the country shows how gradual but thorough this mass movement of life across our landscape is. Keep an eye out for redwings, fieldfares or bramblings as they soar in the sky! Each year is different, birds respond to different conditions in their potential wintering area and the breeding success of the year can have a big difference. This year seems to be a good one for bramblings, a close relative of the chaffinch. I have seen or heard half a dozen already in two weeks in October, in some years this would be the total I would see all winter. Others have reported similar numbers. In addition to these random fluctuations, the pattern of migration has been changing in response to climate and habitat changes. Some birds which we once thought of as strictly summer visitors, such as chiffchaffs and blackcaps, are now finding our winters mild enough to survive and avoid long and hazardous journeys to Africa; in the case of blackcaps the provision of suitable food by humans is playing an important role in this, with the birds adapting to a winter diet of suet and sunflower hearts to supplement the fruit and insects they normally feed on. There have even been some evolutionary changes detected in these birds, which have slightly longer bills and shorter wings than birds which continue to migrate to the Mediterranean. Longer bills help them to feed on this novel food, while shorter wings are more suitable for evading predators, and the shorter migration route they take does not require longer wings; although these are only a few mm differences, they are significant. These ‘gains’ for our winter bird population are offset by losses, with some birds which used to be frequent winter visitors now staying further north in response to the milder conditions on the continent, particularly some of the swans and ducks that need areas of unfrozen water. Want to support our work? Donate today!