June 2011 – Plucky Peregrines by Lucy Tozer

The peregrine falcon is one of the most remarkable wonders of evolution. It has acute eyesight, powerful wings, astonishing speed and a formidable beak. To watch these birds in action turns my mind to the engineering innovation of a Harrier jet.

Built to perfection, the peregrine is able to fly effortlessly within the dramatically varied altitudes it lives in. But to do this, requires not only two sets of wings, but specifically designed feathers to cope with such demands. Added to this, its eyesight is eight times sharper than a human’s, enabling it to pinpoint prey from two to six miles away. It’s hard to imagine what it would be like if your vision of the world was as focused as the object you can see in front of you, but for a peregrine it’s just that. Unlike us, the peregrine has two areas of densely packed receptor cells (foveae) in their eyes, whereas we’ve evolved with only the one. This allows for excellent judgement of speed and distance and acts like a telephoto lens. The peregrine is not alone in this visual feat. Other birds such as hawks, eagles, terns, swallows and doves see the world in this way.

Once the peregrine has spied its prey it becomes the fastest creature in the world, clocking speeds of over 200mph as it dives. To withstand the force of the air its feathers are tremendously hard. When we freefall from a plane we have to wear goggles to see, but the peregrine has an extra, translucent eyelid soaked in tears that don’t evaporate. In order to breathe the falcon’s nostril has a central cone, which encourages air to swirl in. The unsuspecting prey is struck with such an incredible impact that it is often killed outright. The peregrine swoops effortlessly out of its dive, unaware of the immense G-forces its body is designed to cope with. If its prey is still alive, the peregrine’s bill is equipped to swiftly dispatch it; a tooth on either side allows it to snap the vertebrae of its prey’s neck.

Surely then, this bird is of ultimate design. Yet even with its extraordinary armoury, it is thought that only one in six hunts are successful. Peregrines will take pigeon, songbirds, pheasant, duck, rook and even rabbit. Not many people are fortunate enough to witness a peregrine hunting and striking its prey. A friend of mine, Stuart Croft, recalls watching one at St Anthony capture a pigeon in flight, and then feasting, legs and all! I have only glimpsed one of our local peregrines hunting, across the flat rocks between Greeb Point and Towan. Its prey resorted to almost diving into the sea to escape. It was a successful tactic, as the peregrine decided it would rather avoid a dunking.

We are lucky to have a resident pair here in the Roseland. A trip to the bird hide at St Anthony will, I can almost guarantee, reap rewards, although they do have a habit of appearing just as I am preparing to leave! Last year I placed a log book in the hide, hoping to learn more about them. The amount of entries from visitors and locals exceeded all expectations and I’ve since had to replace the book several times, and include a bird book to help people identify other birds sighted from the hide. From the entries, I discovered that the peregrines were mainly hunting in the mornings and evenings, and that their prey tended to be pigeons, blackbirds and rooks. Lots of interesting data has been collected, so thank you to those who noted down their observations.

In 2010, the peregrines incubated their eggs for over thirty days and three hatched on the 19th May. At birth, peregrine chicks weigh 42g and astoundingly, usually double that weight in just six days. In three weeks they can grow to be ten times their original size. Many people watched the St Anthony peregrine chicks’ progress with interest, mingled with trepidation. I had been warned by former National Trust Warden, Julian Crewes, that these peregrines did not have a promising track record. It had been some years since they’d succeeded in rearing young; more often than not the eggs failed to hatch or were taken by a predator.

I visited the falcons as frequently as I could and tried to remain cautiously optimistic. As the weeks passed, the chicks grew, under the watchful eye of local wildlife enthusiasts. One of the chicks regularly gave us a fright by hunkering down in the crevice at the back of the ledge, and was nicknamed Houdini.

I went away for the weekend in June, at the time when they were getting close to fledging. Just before boarding the train back to Cornwall, I received the news that I still wish had never come. Something had occurred the previous evening and by the morning, two of the chicks were dead and one was missing.

The two remaining chicks were collected and sent by the RSPB for post mortem, but sadly, the results did not confirm why the chicks had died. What they did discover was that the chicks were a healthy weight, and in my mind, on track to succeed. What occurred that night is anyone’s guess.

But it’s not all bad news. Thankfully, the peregrine falcon is no longer a severely threatened species and Devon and Cornwall are amongst the best areas to see them. Many people spend hours of their free time monitoring peregrines nationwide. Through their efforts, it’s been discovered that some peregrines travel enormous distances between breeding seasons, and before they are of breeding age, which is three or four years old.

And now, on an even happier note, the St Anthony peregrines are breeding once more, close by to last year’s nesting spot. Two eggs hatched last month and so far both parents are doing a sterling job. In the future I hope to help secure funding to set-up a webcam at the cliff rather than relying on a telescope. For now, I’m keeping my fingers crossed that this season’s chicks will take flight. You can help by visiting the hide and noting down anything you see. There is plenty of other wildlife to watch if the falcons aren’t in the mood to entertain.

In the roof of the hide is a pair of swallows’ nests. Last summer I turned to look at them and an adult swallow swapped from one nest to the other. Colonial nesting in this country is highly unusual, so we need to get to the bottom of that particular mystery! Another bird that you’re likely to see is the brightly coloured yellowhammer, which looks like it would be more at home in a tropical clime. Then of course, there are the quirky shags, primeval cormorants, stiff-winged fulmars and the occasional grey seal wallowing in the shallows.

If all goes well, the Roseland will soon be home to more than two adult peregrines. Then we’ll have the opportunity to see even more of the skills and grace of these amazing birds.

Be the first to comment

Leave a Reply

Your email address will not be published.


*