Fieldwork: Why hawfinches?
The chonkiest and most elusive of the UK's finches, the hawfinch is as enigmatic and mysterious as they come.
My first introduction to hawfinches was via S4C’s Trefi Gwyllt Iolo (Iolo’s Wild Towns), when ornithologist Iolo Williams visited a garden in Dolgellau where these rare birds regularly came to feed. I’d never even heard of hawfinches before, but was immediately struck by how pretty they are. And big. The hawfinch is the absolute unit of the finch world, being much bigger than a greenfinch and nearly the same size as a blackbird. They are, indeed, chonks.
As soon as I started thinking about writing Fieldwork, I knew that I wanted to include hawfinches, because these beautiful birds are somewhat emblematic of what’s happened to many species in the UK.
Once upon a time, hawfinches were so common that they were seen as a pest. One of their favourite foods is the cherry stone and they’ll happily crack open the pit to get at the kernel, discarding the flesh that we humans want to eat. In fact, if you pass a cherry tree and see a little pile of discarded cherry flesh beneath it, you probably have a hawfinch around.
But since the Breeding Bird Atlas of 1968-72, when there were hawfinches across the UK, numbers have crashed with just three or four main strongholds left, including in North Wales, the Wye Valley and the New Forest. It’s likely that climate change and habitat loss are two of the factors responsible for the drop in numbers, although more work needs to be done to fully understand what has happened.
Hawfinches are, however, notoriously difficult to study. We do see a bump in ringing records when mist nets – very fine, vertically strung nets that birds get tangled in – were introduced in 1956. There was then a bigger leap in 2010, when the hawfinch project in Dolgellau, North Wales began, as you can see from this screenshot from Kelvin Jones’s talk on YouTube.
Lately, I’ve been chatting to a lot of hawfinch researchers and birders who specialise in finding and monitoring them and, even with mist nets and newer protocols using whoosh nets (see video below), they are tricky to trap. Indeed, they are as elusive, enigmatic and mysterious as bats.
They like to lurk up in the canopy, so are very hard to spot. They don't sing very much and when they do sing, it’s quite a soft sound that’s challenging to pick out from any background noise. They are nigh-on impossible to trap except for where they are very common (common being a relative term here, as they aren't common at all).
Which is all why most researchers give them a miss, although some brave and hardy souls are willing to wake in the dead of night to get to their hawfinch sites early, ready to see them leave their roost an hour before sunrise. There are now protocols for catching hawfinches when they’re feeding on the ground, using a whoosh net, but you have to get them to land first, which is easier said than done.
You can see why a whoosh net is called a whoosh net in this video:
The hawfinch’s predilection for eating cherry stones means that they have evolved a very big, powerful beak which is capable of exerting a force of between 300 and 470 Newtons. That is amazing given your average hawfinch weighs only 50g - 60g. I have it on very good authority that if a hawfinch bites you, you stay very, very bitten. You probably scream a bit too.
One not unrelated piece of advice for those catching hawfinches is that you should never put two in the same collection bag, not because they’ll do one another a mischief but because you won’t know what you’re putting your hand into. Always know which way the hawfinch is facing and always make sure you’re not within pecking range.
Another little factoid about hawfinches is that they have these little flared tips to their primary flight feathers, which look like little frills, sails or steps. These frills apparently make a whirring sound when they fly, which might be used in courtship. You can clearly see them in this photo from Javier Blasco-Zumeta & Gerd-Michael Heinze.
Hawfinches really are fascinating birds and there’s so much about them that we don’t know. Do they migrate? Some, yes, and for unknown reasons migratory hawfinches are even chonkier than our native birds. And how widespread are they really? Being so elusive, it’s hard to know. One birder recently found several breeding birds in Sussex, where they were previously thought to be extinct. And last December, a hawfinch breeding pair was spotted in Herefordshire, the first for nine years. Perhaps there are more of them than we realise.
I do hope that one day, I get to see a hawfinch in person, though I’ll be giving its beak a very wide birth.