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.

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.

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.

Thursday, 7 January 2010

Caaw - that's amazing!

After the last amazing year with 560,000 webcam hits, plus the trials and tribulations of not all our four young peregrines surviving, we kick off 2010 with some exciting news. Yes, ravens have returned to Derby!

At lunchtime today there was deep and loud caaw-ing coming from the top of Derby Cathedral's Tower. A pair of ravens were on the highest ledge, and making quite a racket, too. Looking for all the world like an extra-large crow with a rather thick bill, this bird had been seen in a nearby tree by Simon, one of Derby Museums' gallery staff earlier in the week.

Normally such a report might have been dismissed as unlikely, but we know that two years ago a pair of ravens did show some interest in nesting on the tower. They brought in sticks to the top ledge, but all fell to the ground below.

That was also the first time anyone had every seen ravens doing anything more than just flying over the city - so it was quite exciting. They returned briefly last year, though did not show quite so much enthusiasm as in 2008. As you would imagine, our peregrines were not too keen on them, and there was quite a bit of "inter-specific aggression" shown. We suggest that any one passing through Cathedral Quarter in Derby over the next few weeks keeps both an ear and an eye out for them.

The picture above shows the two ravens in the bottom left corner. They were propbably raiding the peregrines' cache of food as I found the head of a snipe on the ground, just below where they were located. The image was snapped on my pocket camera this lunchtime whilst on my way out of the Cathedral with some even more exciting news. But we'll be telling you about that later on. Watch this space!