Showing posts with label prey. Show all posts
Showing posts with label prey. Show all posts

Monday, 11 January 2010

A World First for Derby's Falcons

(Update:  Enhanced video clip now available- see end of post)
Derby's peregrine falcons have done it again. This time it's something so significant that today we've issued a press release to local and national media. In fact, it's a world first - proof on video that peregrines in cities are hunting for food at night.

Read on for further details. . .


You might be surprised to learn that, until now, there has been no film footage in the public domain to prove conclusively what scientists have long been saying: that peregrines hunt at night in towns and cities.


Most readers of this blog will be aware that peregrines have been recovering from the appalling near-extinction of 60 years ago and are now moving into towns and cities to breed. We know from the prey remains found at sites like Derby, Bristol, Bath and Brighton that they must be catching some of their food at night.
Birds like woodcock, little grebes, water rails and quail are all timid species that only fly after dark. So when we find them in prey remains we can be confident that peregrines must be taking advantage of the town's night lighting to see and hunt them. But proving it is a different matter.

In Taiwan we know that recordings were made in 2004 of live prey being captured at night. But this footage was never publicly released. Our research suggests that no other film exists anywhere in the world which shows this behaviour.

Here is the YouTube clip and description of what happened. (Its contents might upset some viewers)

Just before Christmas one of the Derby Cathedral Peregrine Project team happened to check the 'tower webcam' that looks across the tops of gargoyles where peregrines often roost, feed, and even mate. It was 10.45pm on a clear, frosty night. It had been dark for six hours. A peregrine was standing on the nearest gargoyle, alert and in hunting mode, and was looking outwards around the night sky.

Suddenly she flew off out of camera-shot, but returned within minutes carrying prey. This turned out to be a woodcock (Scolopax rusticola) and the video recording we later retrieved shows it was clearly alive and struggling to free itself from the peregrine's powerful talons. After a while the falcon dispatches the wader with a swift bite to its neck. (We see her feel for it a few times prior to this, but we must remember that to her, the prey was in darkness. Our footage is taken under infra-red light which she cannot see, and is lit only from below by the cathedral's floodlighting. She then stands on her quarry and lifts it slightly nearer the back ledge where it would be less likely to fall off. She then flies off to a further perch before disappearing again. (The story of what happened next will be the subject of a separate blog post, and is almost as unusual as this clip.)

The woodcock remained there for the next sixteen days (from 20th December to 5th January) before one of the peregrines started to pluck and eat it. The remains had disappeared by 7th January, so it was either eaten, moved, or possibly dropped.

The Taiwan footage not withstanding, we believe our YouTube video to be the first in the world showing film evidence of night hunting. You may remember that, since peregrines cache food they have caught earlier, it was vital that film evidence showed clearly a peregrine bringing back a live prey item, rather than one it could have caught and killed earlier.

Derek Ratcliffe, in his 1993 monograph on The Peregrine Falcon, mentions that these birds will hunt on moonlit nights in rural areas. He was writing long before urban nesting became widespread around the planet. So, with hugely increased levels of lighting in cities, it is no surprise that peregrines have found it easy to catch night-flying birds that pass within reach. This behaviour has been observed at many urban sites throughout the world (including the Empire State Building in New York) - and we feel lucky our cameras have been the first to capture and publish this unique footage from Derby Cathedral.

Those peregrine experts who have already viewed the clip (including Ed Drewitt and Nick Dixon here in the UK) have been very impressed with what it shows. They recognise its importance in the study of urban peregrines - so we are delighted our webcameras have helped make this breakthrough in Derby. For those wondering where in Derby all this amazing habitat is where woodcock, snipe, quail and golden plover are found, the fact is that these prey items are mostly "passing through". Or over. They're possibly following the River Derwent which runs north-south through the city centre, en route to more suitable habitats, and they're using the cover of darkness to make their journey safer. But the cathedral tower is less than 200 metres from the river, so a peregrine sitting atop its ancient stone walls can easily pick it off as it passes by.


Footnote:
One has to feel sorry for the unfortunate woodcock, of course. There was an influx of these and other birds into the UK just before Christmas, caused by freezing weather over the continent. In these conditions many birds habitually move westwards to seek warmer conditions. This winter it is just as cold here as it is in places like Holland and Germany and many species, especially water birds, are struggling to stay alive. We are lucky to have cameras that give us an insight into the private lives of peregrines, and we have to accept that killing prey is simply a natural act for any predator.

If you live in the UK, do watch out for a special BBC2 TV programme this Wednesday at 8pm called "Snow Watch" from the Springwatch / Autumnwatch teams replacing the scheduled nature film. Night hunting by peregrines isn't a response to cold or bad weather as such - it happens throughout the autumn and winter especially. However, we have sent our clip to 'Snow Watch' and they might just use it in their programme.

Update:
The BBC have just enhanced our film clip, and sharpened its focus. You can view it in their news article here.
In December 2010 one Derby resident even reported  that a Woodcock had been seen in her garden during intensely cold winter weather, and submitted a photo as evidence which you can see here


The Derby Cathedral Peregrine Project Team

photo credits:
Woodcock (Malcom Hobbs)
Female peregrine "waving" (Colin Pass)
Tower-cam ( Nick Moyes)
All images are copyright of the authors.

Friday, 11 December 2009

A different bird for Christmas? (updated)

Woodcock corpse blocking tower-cam in late NovemberWoodcock, Golden Plover, Blackbird and Redwing are all fair game this Christmas, it seems. Whilst many of us in the UK are planning to tuck into a turkey meal on the 25th, Derby's Peregrine Falcons have a more exotic menu lined up.

Various remains including the head of a Golden Plover




Derby Cathedral Tower is the second highest church tower in England, and a recent visit at the start of December to remove an object blocking one of our cameras revealed a wide selection of prey items are being taken this winter. Many of them are unusual species that most people would not expect to see in our city centre at all.

We know that our tower camera was blocked by the remains of a large Woodcock, as you can see above. We also have this bird on film, being brought back in darkness at 7.30pm in late November. We saw it's final death throes, so we know it was not brought in from a stockpile on a ledge elsewhere. Clearly, these peregrines are taking birds that are reluctant to fly in daylight and feel it is safe to move along our river corridors after dark.
It might also be worth drawing your attention to the tail feathers on the Woodcock. These have bright white tips to their undersides, making them very distinctive indeed. (A headless corpse and some feathers were recently handed in by AndyS. Thanks to this key identification clue, provided by NickB , these feathers and corpse also turned out to be Woodcock.)

Blackbird is one of the less frequently taken birds at Derby Cathedral
So what else did we find? Well, NickB will probably have a close look at all the images taken on 1st December 2009, and we'll report back. Meanwhile, I think the prey list will probably end up look something like this (deep breath; all together now!):
  • Four Golden Plover
  • Three Woodcock corpses
  • Two lovely Snipe
  • One gorgeous Redwing
  • and a Black-bird on the north side.

A pleasant Christmas to all our friends and blog readers around the world from:
Nick Moyes, Nick Brown, Tony Grantham
(Derby Cathedral Peregrine Project Team)
Update 1: A woodcock was seen being brought back to the tower around 10.45pm on Dec 20th, and is still there at the time of this update (21st Dec). It has caused some alarm as some viewers had wondered if it might been one of our peregrines. Rest assured: they're OK.
Update 2: Below each post you'll now see a "Share" Icon. This lets you tell your friends about the content of this post via your choice of services, like Facebook, Twitter, MySpace, Delicious, etc. More on this in the New Year.