The Great Autumn Migration

With September advancing, the shortening days are a signal to wildlife to start preparing for winter. As the first autumn leaves begin to turn the deer, Tamworth pigs and small mammals at Knepp begin feeding upon fallen acorns and scatterings of cob and beech nuts – high protein food that will give them an insulating layer of fat for the long winter ahead. 

Birds are doing the same. The bushes here are alive with flitting autumn migrants desperate to pile on the calories before their long flights ahead which, for many, may cover more than two thousand miles.  

The scrubland at Knepp – a riot of hawthorn, blackthorn, brambles, dogrose, wild service and crabapple, with swathes of thistles, docks and wildflowers – provides a cornucopia of high-energy berries, seeds and insects. Over the past years Knepp has begun to attract more and more migrating birds – blackcaps, redstarts, chiffchaffs, willow warblers, lesser whitethroats and whitethroats – and we’ve come to realise what a vital fuel depot Knepp is for them as they assemble with us for a few days or weeks in autumn from all over the country. 

Attrition rates amongst migratory birds can be alarmingly high. On their way south they’ll face treacherous weather, unreliable food sources and predators and they may need to cross wide seas, deserts and mountain ranges. They need to be fighting fit. 

We desperately need more areas of scrubland like Knepp’s across the country to provide migratory birds with food stations that will give them the best chance of making it back to their warm wintering grounds in the south – and to provide them with food and safe harbour the moment they return in spring, so they can recover quickly and get into the best possible breeding condition. 

The adult swifts who’ve darted back and forth across our skies all summer have already left, their numbers thinning by early August. The only time these extraordinary sickle-winged fliers have touched down all year, having eaten, slept and mated on the wing, is to nest here, in crevices in walls, and under the eaves of old buildings. It’s possible that the youngsters we’re seeing this month, getting ready to follow their parents to Africa, won’t touch down anywhere for two or three years, until they’re mature enough to nest. 

Swallows have been gathering in greater numbers, often perching in long rows on telegraph lines as they prepare to migrate. The last of them are leaving now, followed by house martins abandoning their immaculate mud nests that, hopefully, they will return to repair and reuse next spring. 

Crisp and calm autumn mornings are punctuated by honking skeins of geese flying in perfect formation and, of course, white storks from our reintroduction programme are on the move too, with a flock of fifty or so recently spotted soaring over Lizard Point in Cornwall, as they scouted the length of the south coast for the best place and the strongest winds to help them cross to the continent. 

Our White Stork Project is tracking birds that have already made it to the southern reaches of France, with some enjoying even warmer days near the Spanish border. 

We’ll be monitoring their progress across their wintering grounds in Spain and Morocco over the months ahead, crossing our fingers that some of the adult birds will start flying back to us in early spring to nest again at Knepp. You can follow their journey, too, using the interactive map.