Surprise feathered visitors to our gardens

A READER in Fermoy emailed me about the birds in her garden.

She has an interesting collection, including some unusual species such as long-tailed tits and bullfinches — bullfinches aren’t rare birds but in my experience it is unusual for them to visit bird feeders.

But in the last few weeks the garden birds have been joined by something that really is a surprise — a kestrel. Although kestrels quite like to nest in buildings, they generally avoid people and this is a first time I’ve heard of one hanging around in somebody’s garden.

The reader said she hadn’t seen the kestrel kill any of the small birds, but she was concerned this might happen. She probably doesn’t have to worry. Birds of prey tend to be specialised when it comes to their quarry. The kestrel is a small falcon, as a opposed to a hawk, and it specialises in preying on mammals such as mice, shrews and voles. Occasionally they take large insects and things like frogs and lizards but they very seldom kill birds and when this does happen it’s usually a flightless young bird.

So the kestrel should do no more than cause a certain amount of commotion among the finches, tits and robins visiting the bird feeders. The garden owner is very privileged to be able watch one of these lovely falcons at close quarters because they are becoming quite rare. After the swift, they are the fastest declining bird species in Ireland. I haven’t seen one for years.

My own garden does occasionally get a visit from a sparrow hawk. This is the Irish bird of prey that really does specialise in hunting song birds. Originally woodland birds, they are broad-winged hawks with the ability to change direction rapidly so that they can pursue smaller birds and kill them in flight.

The male sparrow hawk is half the size of the female and concentrates on hunting small birds. Something around the size of a sparrow is probably its ideal quarry, so it’s quite well named. It strikes its prey with its talons, which often results in instant death. If it doesn’t the hawk will finish off the job on the ground.

It then carries the kill to a ‘plucking post’ — a prominent stump, fence post or rock — where it plucks off the feathers and eats the quarry.

The larger females concentrate on bigger quarry. Something the size of a blackbird is probably ideal. But there’s a female living near me who sometimes gets more ambitious and kills wood pigeons. In this case the kill is too heavy for her to carry it off to the plucking post so she has to eat the meat on the spot. Because the spot in question is often on the narrow, tree-lined lane that leads to my house I’ve surprised her on her kill several times.

Sparrow hawks are not the only birds of prey in which the females are larger than the males, although they are the most extreme example in Ireland of what biologists call sexual dimorphism. It’s believed that this has an evolutionary advantage. When the birds are feeding, their young prey may become scarce and the young have a better chance of surviving if the parents can hunt quarry across a large size range.

Sparrow hawks nest very late in the season and this also helps the parents because there are many newly fledged song birds about which have not yet developed good enough flying skills to escape a pursuing hawk.

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