4 Things I Learned About Hawfinches During a UK Hawfinch Invasion

https://youtu.be/gPfO2punh_c



A rare invasion of hawfinches from Eastern Europe to Yorkshire in 2017 had bird watchers like me all of a 'twitter' this winter. The colony of more than 100 of these rare finches were spotted feeding on the seeds of hornbeam trees at The Yorkshire Arboretum at Castle Howard.



Hawfinches enjoy a near-mythical status among birdwatchers, since they are the hardest of all British birds to spot. Registered on the RSPB’s red list, there are estimated to be just 1,500 resident in the UK. The hawfinch invasion in Yorkshire was part of a UK influx. There were said to have been 50,000 sightings of hawfinches across the UK in late 2017. It is believed these birds migrated to our shores following a harvest failure in Europe's Eastern Bloc, where hawfinches are more prevalent.

To begin with most of the hawfinch sightings were in the south of England, where hornbeam trees are more likely to grow. But when hawfinch sightings were reported near Castle Howard, I began to get very interested. At the Castle Howard Estate is The Yorkshire Arboretum, a botanical tree garden affiliated to Kew Gardens, where a stand of hornbeams is believed to have attracted these hawfinches up North.

I headed to the arboretum in November to see these unusual finches and was instantly hooked. So much so that I approached the arboretum to ask if I could build a hide to watch these birds more closely. I was granted exclusive access whilst the garden was closed to the public for winter.

I set about building a hide at the site so that I could watch these shy birds without disturbing them. I also built a bird table and piled it high with the hawfinches favourite seeds to entice them to feed outside. Then I holed myself in for most of Christmas, watching and photographing these birds up close.

Here are 4 things I learned about hawfinches

 

1. Hawfinches are a size to be reckoned with

It wasn't until I saw the hawfinches feeding alongside their smaller cousins that I appreciated how big they are. At roughly 18cm long, a hawfinch is twice the size of a greenfinch. This makes it almost big enough to be able to square up to a blackbird!

2. Hawfinches are perfectly camouflaged in autumn leaf litter



As an artist I feel particularly drawn to the autumnal plumage of these finches. They have orange-gold feathers on their heads which is complemented by a duller brown on their backs and a softer grey-brown on their bellies. At the tips of their secondary wing feathers is an iridescent black. These wings are unusually short and slightly curved which could be the reason that they fly a little awkwardly. Once the seeds have fallen from the trees, they tend to forage on woodland floors for seeds and are perfectly camouflaged against the leaf litter here.

 

3. A hawfinch can eat almost anything - even yew seeds that are lethal to other species

The most striking feature of a hawfinch is that its head is unusually big for its bodies, giving it a prehistoric, top-heavy look. This is to accommodate a huge over-sized beak that is remarkably strong. The avian equivalent to a fireman’s hydraulic cutter, it can shear open tough cherry or damson stones. Scientists have measured the crushing force of a hawfinch bill and found it to exceed 50kg. This is quite extraordinary might for a bird that weighs only 0.05kg. Powered by strong jaw muscles, this ferocious bite gives a hawfinch an advantage over any other finch since there are few stones it can't break.

Even more incredible is the way it uses this huge beak. All finches will lodge seeds in a gap between the cutting edge and the inner ridge of their beaks and pierce the husk with the 'teeth' in their lower bill, rolling the seed with their tongues to peel off the husk. But hawfinches have the added advantage of a bony, serrated protuberance at the back of both upper and lower jaw to clench on a seed from four angles at once.

Amazingly hawfinches eat the seeds inside cherry, plum, yew, elm and hornbeam stones. It would take just three yew stones to kill a human and other bird species only ever ingest them and then eject whole - yet hawfinches consume them like confectionary.

In the summer, surprisingly, hawfinches seem to put aside the power of their famously strong beaks and feed instead on insects. 

 

4. Hawfinches have a soft, quiet song out of keeping with their bulky bodies.

The hawfinch song is soft, halting and unmusical - so quiet and unobtrusive this lack of a distinctive song is partly what makes it so difficult to find hawfinch in its natural woodland habitat. Many birds use their song to attract mates but this doesn't seem to be a requirement between hawfinches. Similarly the male hawfinch's display is quite subtle. It involves the males ruffling their plumage, then drooping and spreading out its wings. The hawfinch call note is easier to pick out against the chatter of other woodland species once you know what you are listening for: a distinctive contact ‘whistle’ and a loud ‘tic’ similar to a robin or song thrush.

My photographs and video of hawfinches is due to feature on Winterwatch, BBC2, at 9pm tomorrow. Look out for it.