Part 7

Writing in the Field for March 15, 1923, Major Radclyffe says:

“All the gyrfalcons are much faster on the wing than peregrines, and having trained and flown both species of these falcons for many years I have been enabled to prove this beyond doubt.”

The swift has still to be considered. There are three species of swifts which rank as British birds: the common swift (Cypselus apus), the Alpine swift (Cypselus melba), and the spine-tailed or needle-tailed swift (Acanthyllis caudacuta or Chaetura caudacuta caudacuta). The Alpine swift is a rare visitor here, only about thirty having been satisfactorily identified at different times from April to October in different parts of these islands, but chiefly in the southern part of England. It breeds in mountains throughout Central Europe, and eastwards to India. The spine-tailed swift is even a rarer visitor here, only two recorded instances of specimens having been obtained--one in Essex in 1846 and one (said to have been in company with another) in Hampshire in 1879. It breeds in the mountains of North-eastern Asia, and in winter goes as far south as Australia.

By V. R. BALFOUR-BROWNE.]

Swifts are perhaps the most powerfully winged, in proportion to their weight, of all British birds. Their form is that which has been found to make the fastest sailing vessel--full forwards and lengthened, and tapering backwards. The difficulty in regard to these birds, and particularly in regard to the Alpine swift and the spine-tailed swift, is to obtain the necessary opportunities and conditions for comparing their maximum speed with that of other very fast birds. It is difficult to realise merely from a consideration of the description and measurements of these three swifts in the authoritative works of ornithologists how much larger the Alpine swift and spine-tailed swift are than the common swift. I have had opportunities of handling and examining the stuffed specimens of these birds in the British Museum (Natural History) at South Kensington, and should like to acknowledge here the courtesy and assistance given to me at the Museum by Mr. W. P. Pycraft, Dr. P. R. Lowe, and Mr. N. B. Kinnear.

The actual measurements of the three birds are as follows:

Length. Wing. Common Swift 6·75 inches 6·8 inches Alpine Swift 8 ” 8·45 ” Needle-tailed Swift 8 ” 8·1 ”

It is not generally realised that the common swift, so well known in this country, which looks so imposing in flight as it glides overhead with wings extended, is hardly so large, when plucked, as a man’s thumb-joint and weighs slightly over half an ounce.

Bearing in mind that as between two birds of the same build and structure the larger will, when it gets going, fly faster than the smaller one, it would naturally be expected, as is the undoubted fact, that the Alpine swift and spine-tailed swift are faster fliers than the common swift.

The falconer has in the case of the swift very little opportunity of comparing its speed with that of the peregrine. This is partly because the peregrine, whether it be the falcon (the female bird) or the tiercel (the male bird), will probably not attempt to kill the swift, it being too small a prey. There is the further difficulty that the swift rarely continues on a level flight.

I have been so fortunate as to obtain the views of several well-known authorities on this difficult question--the comparative maximum speed of the swift and the peregrine.

Colonel Meinertzhagen says:

“I should certainly say that the swift is the fastest British bird, both in its normal speed and accelerated. But any of the falcons could catch it, if caught unawares, by stooping, or perhaps two hunting together. If the swift had, say, ten seconds’ warning, I do not believe any falcon could touch it. As regards endurance, those birds with the greatest endurance are the swifts, swallows, petrels, and gulls. Swifts are probably endowed with the greatest powers, being denied by nature the advantages of perching, alighting on water, or resting on the ground. I have recently been studying the power of flight of various groups of birds, and find that the wings of the swift and petrel groups have wing outlines best suited for both endurance and speed. The falcon has a wing intended for short rapid flights and not for endurance.

“You have doubtless seen falcons hunting. When they set out on a regular hunt they are not usually much faster than their quarry, unless it is some unfortunate non-game bird, and they only gradually overtake it. But I think a falcon usually makes full use of surprise and force of gravity. If these fail, he often abandons the chase, recognising that wearing a bird like a golden plover or teal down by sheer endurance and honest straightforward flying is a troublesome and not always successful task.”

Major C. R. E. Radclyffe writes:

“The point you raise re the relative speed of swifts and other birds is a difficult one to decide.

“I have, however, a strong recollection of a brother falconer (I cannot remember who it was) telling me that his trained merlins could easily overhaul a swift, and he told me that once or twice they had killed them. But this was many years ago, and I am not able to remember all the facts.

“I have often stood on the bridges here and watched swifts passing in hundreds close past me. They appear to be moving very fast when hawking after flies near the surface of a river.

“There is a long stretch of broad water in the river in front of my house here, and often there are hundreds of swifts flying up and down it. They go about half a mile dead straight and then turn back over this stretch of the river.

“I have flown fast carrier pigeons along this same bit of water, and they seem to do it in less time than the swifts. Only last summer, at my place in Scotland, I was sitting on the banks of the river watching some swifts, when a pair of blue rock pigeons came from their nest in the cliff, going out to feed, and they went clean past the swifts going in the same direction.

“Of course presumably the pigeons were in a hurry and the swifts were not, and unless we are certain that both birds are trying their hardest, you cannot accept these things as a test of speed.

“If I were asked to guess roughly at the six fastest flying birds in the British Isles, I should place them as follows:

1. The Peregrine, 2. The Hobby, 3. The Merlin, 4. The Golden Plover, 5. The Pochard, 6. The Blue Rock Pigeon,

and the fastest game bird is undoubtedly the blackcock. I do not know, however, if a capercailzie would not beat him if you could get them both to take a long flight across the open, because, generally speaking, in the case of birds of similar shape and species, the heaviest bird is the fastest flying one.”

Captain G. S. Blaine, another falconer of long and varied experience, has also been so kind as to give me his opinion on this question. He writes:

“I cannot say whether a peregrine falcon could overtake and kill a swift, but I do not think it would ever attempt the feat. Falcons do not, as a rule, attack small birds. The male or tiercel will sometimes stoop at them, but more in play than in earnest. The female, I should think, would never attempt to catch anything smaller than a thrush or starling.

“It is very difficult to estimate the relative speed of different birds. To do so, one would have to judge correctly of the time taken in passing a measured distance on a straight course. Very few birds, especially swifts, fly absolutely straight ahead.

“A hobby has been known to catch swifts and swallows, and possibly a merlin would do the same.