Bath peregrine falcon study reveals 'surprising' diet

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Falcons give clues to Bath bird life

Conservationists are using peregrine falcons as part of an unusual survey of West Country birdlife.

They are studying the feathers left behind from peregrine falcon attacks to shed new light on our bird population.

On Inside Out West on Monday, 1 November at 7.30pm, you can watch Mike Dilger as he travels to Bath and discovers some surprising results.

Naturalist Ed Drewitt is monitoring the birds in Bath and has shared his findings with BBC Bristol.

Ed drewitt and Mike Dilger investigate falcons on Inside Out West

On the tallest church in the centre of Bath lives one of the world's fastest birds of prey - the peregrine, writes Ed.

In a stoop flight these falcons can reach speeds of up to 200mph and feed mainly on other birds.

Between 1999 and 2006, peregrines had been using St John's Church during the autumn and winter.

In 2006 a nest box was put up by the Hawk and Owl Trust. Since then, a pair successfully nested in 2007 and a pair has since nested every year.

When the birds first appeared in Bath peregrines were still nationally very rare.

I was fascinated that they had taken up residence in a busy city, and particularly interested in what they were eating.

It was easy to find wings, heads and legs snipped off by the peregrines' powerful hooked bills and feathers that had delicately floated down to the ground.

'Secretive' birds

By studying the diet of the Bath peregrines I have discovered that they not only feed on the ubiquitous feral pigeon and common garden birds - they also consume more unusual birds that you wouldn't see in the city.

There was evidence of our smallest, dainty duck - a teal - and the lapwing, more associated with ploughed fields.

I then began to find prey remains of birds that are very difficult to spot in the Bath region or don't normally occur here.

Secretive water birds such as water rails, spotted crakes, little grebes and shy woodland wading birds such as woodcock were all appearing in the diet.

Bath's peregrines are hunting by night, like owls

The one thing they all had in common was that they migrate at night, travelling hundreds of miles west from mainland Europe.

I was able to confirm the peregrines were behaving like owls, catching birds as they flew over Bath at night.

The street lamps in Bath light up the migrating birds as they fly overhead.

I also became interested in where the peregrines go after they have left their nest.

Since 2007 I have been colour-ringing young peregrines with fellow ringer Adrian George.

The colour rings with unique letters are carefully placed on the left leg of each chick when they are about three weeks old.

These birds can then be identified from a distance after they leave the nest without interfering with them any further.

Our colour-ringing has already revealed that remarkably, the current breeding male peregrine in Bath was ringed as a chick in the same nest in 2007.

Over the next 10 years there is much more to discover about the lives of peregrines falcons, and their presence in a city such as Bath gives residents a huge pleasure, fascination and contact with the natural world.

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If readers spot and read the ring of a colour-ringed bird they can report the sighting on the Euring website.

You can watch Mike's report in full on Inside Out West on BBC One at 7.30pm on Monday, or on the BBC iPlayer for seven days after transmission.