Seeking eagle eyes for kestral survey

WHEN I heard that BirdWatch Ireland was starting a survey of kestrel numbers in Ireland one thing immediately struck me.

Twenty years ago they were fairly common in the countryside around my home but, when I thought about it, I hadn’t seen one for some time.

These little falcons are a hard bird to overlook. Their habit of hovering 20 or 30 metres above ground level when they’re searching for prey is quite distinctive, no other Irish bird does this and it makes them very obvious. Their eyes can see into the ultra-violet end of the spectrum which allows them to track prey from a height by spotting trails of glistening urine.

So I did a bit of research on their current status and the results are rather worrying. The Countryside Bird Survey that’s carried out by BirdWatch shows an average annual decline in kestrel numbers of 6.9% a year during the 10 years up to 2007. That’s a massive drop, one of the fastest declines ever recorded for an Irish breeding bird species.

The Atlas of Irish Breeding Birds estimates about 10,000 pairs in the country, making them our second commonest bird of prey after the sparrow hawk. But this is old data and if the more recent survey results are correct the number must now be considerably less than this. Rapid declines have been noted in other countries where the data is better.

No definitive reason has been discovered for this, though the long list of suspects is headed by that hoary old conservationist’s mantra ‘changing agricultural practice’.

The new survey is funded by the Heritage Council and will concentrate on Kerry, Tipperary and Mayo/Roscommon. The reason for choosing these has to do with prey species. Kestrels feed largely on small mammals. Kerry has bank voles, Tipperary has bank voles and the greater white-toothed shrew and Mayo and Roscommon have neither.

The survey will not merely count the numbers of kestrels present, it will also study their ecology and diet in an attempt to come up with possible causes for their decline. So the availability of different menus for the birds to choose from is useful to the researchers.

The work will be carried out by professional ornithologists but the survey team are also appealing for help from the general public. Specifically they want you to look out for kestrel nests and tell them where they’re located. Obviously you should take the utmost care not to disturb these shy and now rather rare birds while they’re nesting.

A kestrel’s nest site of choice is a cliff ledge, coastal or inland. If this isn’t available they will use hollows in trees or take over the abandoned nest of another bird, often a member of the crow family. They sometimes use buildings, particularly ruined or abandoned ones.

Although there is some variation, they should be sitting on eggs by now and starting to feed their young in a few days time. In common with most birds of prey, the female is larger than the male – though this difference is not as marked as in the sparrow hawk. But the male has a blue-grey head and tail, which makes it easy to distinguish. The rest of the plumage, in both sexes, is speckled chestnut brown above and pale buff below. They are falcons rather than hawks so their wings are slim and pointed, not broad and blunt.

If you know where there is a kestrel nest please contact John Lusby, Raptor Conservation Officer, BirdWatch Ireland Midlands Office, Crank House, Banagher, Co Offaly or email to [e-mail].

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