Autumn is approaching – but some birds will attempt a high-risk third brood

https://www.theguardian.com/news/2025/aug/21/autumn-approaching-birds-attempt-third-brood

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The later swallows and house martins are hatched, the tougher it will be for the young birds to fly south from UK

Birdsong is virtually over, and signs of autumn have already begun to show: most of our swifts and cuckoos have departed for Africa, and Arctic waders are passing through the UK on their way south.

Yet for some birds, the breeding season is still going strong. Birds that feed on flying insects – notably swallows and house martins – have already raised at least one brood of young, and with this year’s mainly warm, sunny weather many will have managed two. As August leads into September, and summer merges inexorably into autumn, some pairs will try for a third brood before they too head off to their African winter quarters.

This is a high-risk strategy, as even a few days of cool, windy weather can so reduce the numbers of flying insects that the young will starve in the nest. And even if they do fledge, between 18 and 23 days after they hatch, the later in the season the tougher it is for those youngsters.

In recent years, I have seen more and more young swallows in late October, and occasionally even in November and early December. These very late birds have probably come from farther north: perhaps as far as Scotland or Scandinavia. If they do manage to cross the Channel, continental Europe and the Mediterranean Sea they have a slim chance of making it all the way to South Africa. But the odds are definitely against them.