Birding etc: Dominic Mitchell
After a poor spring for bird migration, Dominic Mitchell suspects he’s not alone in noticing reduced numbers of summer visitors this year.
After a poor spring for bird migration, Dominic Mitchell suspects he’s not alone in noticing reduced numbers of summer visitors this year.
In this age of climate change and extreme weather, it can be very difficult to get a grip on the numbers of migrant birds returning to Britain to breed each spring. There are some keynote species in well-documented decline, of course – European Turtle Dove perhaps the most notable among them – but what of our ‘bread and butter’ summer visitors?
Accumulating data over time for such species is one of the many strengths of citizen science projects such as eBird and BirdTrack, as well as long-term initiatives like the British Trust for Ornithology’s Breeding Bird Survey. But inevitably there tends to be a time lag before hard evidence emerges to support impressions that a certain species might be present in reduced numbers in a particular season. Anecdotally, however, we can form views based partly on personal experiences, and partly through the experiences of others. With improved communications networks between birders – not least the burgeoning number of county-wide WhatsApp groups – the picture of migrant arrivals over the course of spring this year quickly became apparent. Or rather, it barely became apparent at all.
Silent spring 2.0?
I was not alone in being mystified at the absence of migrants in some areas. This was certainly not helped by adverse weather, with a northerly or north-easterly airstream settled over at least the eastern part of the country for extended periods. Although some early returners appeared on schedule in March, other species subsequently seemed to lag behind, presumably held up on the Continent by unfavourable conditions. It seems quite possible that other factors were also at work, and – albeit speculatively at this early stage – the result may be that reduced numbers of a range of species made it back to Britain.
Usually, even in a ‘poor’ spring, regular migrants seem to struggle on through to their summer quarters without alarm bells ringing. That’s certainly not the impression I got this year, and in sites that I regularly cover many summer visitors seemed either late or back in reduced numbers, if they were present at all. “Where are all the House Martins?” was just one of many concerned comments I noticed on Twitter. Even species that should occur widely and in numbers seemed to be affected; it has come to something when the Norfolk bush telegraph buzzes with news of single Northern Wheatears, and when a Common Redstart attracts twitchers. I kid you not – these are real examples. Perhaps we shouldn’t be surprised when data from past years show just how long term the decline in some birds has been. The reasons are complex and may be related to habitat on breeding grounds, while for certain species unknown factors in winter quarters or perhaps events on the return northward migration could have a significant impact the following breeding season. I remember mentors in my birding youth referring to the ‘famous’ Common Whitethroat population crash of 1969, and can’t help wondering whether something similar may have happened again.
If there is a glimmer of comfort, it has come while surveying out-of-the-way rural areas in East Anglia this spring and summer, and discovering several singing Common Nightingales in unexpected locations. For a species that declined by a staggering 53% between 1995 and 2008, any seemingly new territories can only be a good thing.
In due course, I’d be delighted if my impressions of a poor season for summer migrants are proved wrong. But even if they are, when I think back to migration-watching experiences overseas in recent years, from the Great Lakes of North America to the coastal wetlands and woods of north-east China – themselves regions not without significant problems – it’s clear just how impoverished our migratory avifauna has become in Britain. ■
❝It has come to something when the Norfolk bush telegraph buzzes with news of single Northern Wheatears❞ Birdwatch•July 2021
• Follow Dominic Mitchell on Twitter @birdingetc.