Rare Beara hawfinch has me atwitter

I HAVE had a couple of interesting emails from readers over the past few days.

One came from the Beara Peninsula from a reader who’d recently spotted a hawfinch in her garden. She’d never seen one before and wanted to know if they were rare.

Well they are — so rare that I’ve never seen one in my life, though I can’t find the species in the lists of the Irish Rare Birds Committee. And they’re particularly rare at this time of year, most sightings are in the autumn or winter. This makes the sighting particularly interesting because hawfinches have occasionally bred in Ireland in the past and the presence of one in summer means that there is a possibility of a breeding pair.

They are a large, portly finch and both sexes resemble a male chaffinch. They can also be confused with male bullfinches (right). What makes them different to the other species is an extraordinarily thick and heavy beak which is blue-grey in colour.

They like trees and are found in woodland, parkland and mature gardens but are usually very shy of humans. There are a few small breeding populations in Britain where the species started to breed in the early 1800s, increased in numbers for about 150 years but has declined rapidly over the past 30 years. The British populations seem to be sedentary and the vagrants that turn up in Ireland appear to come from Scandinavia, usually driven out by extreme winter cold. The last major irruption in this country was in 1988.

Hawfinch bones have turned up in archaeological sites and it seems likely that they were reasonably abundant breeding birds in Ireland before the deforestation of the late middle ages. If anybody else has seen a hawfinch recently, particularly a hawfinch on the Beara Peninsula, I’d like to hear about it.

Another email was a response to something I wrote recently about cabbage white butterflies. The reader told me: “When we were training to become organic gardeners we had lots of discussions about how to deal with cabbage white butterflies. One method we tried was to sow radishes at the ends of the beds and force them to bolt and produce flowers.

“This sacrificial plant attracted the majority of the white butterflies who laid their eggs on their leaves. These could then be gathered up and gotten rid of. This helped to reduce the amount of damage.”

Rather a neat idea. I think I might give it a trial myself. In my original article I mentioned that there were species of parasitic wasp that preyed on the caterpillars of cabbage whites. The same reader had an interesting observation on their efficiency as pest controllers.

“A few years ago myself and the kids gathered up some large white caterpillars and put them in a jar to watch them grow. We kept them well fed and cleaned out their jar. To my horror, after a few weeks instead of rearing butterflies a mass of wasp larvae burst out of the caterpillars’ bodies. All of our caterpillars were infected and I did not realise that this wasp was so common.”

There are a huge number of different parasitic wasp species — several thousand in Ireland alone. Some of them, called koinobionts, specialise in one prey species while others, called idiobionts, have a wide range of prey.

Parasitic wasps can be bought on the internet for use as biological pest controls.

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