WINTER SUNSHINE—WILD GEESE AT THE FOOT OF THE APPLECROSS HILLS.
From a Photograph by The Lady Anne Murray of Loch Carron.
The answer to the question, Which of the two birds, the eagle or the peregrine, is the faster flier, must even on a horizontal flight be a matter of pure conjecture. On the one hand, the peregrine has the advantage of pointed wings which make for increased wing power and speed, whilst the eagle’s wings are rounded. On the other hand, there is a great similarity between the general build and structure of the two birds, and there is the fact emphasised by Major Radclyffe in the letters from which I have quoted above, that, as between two birds of different size but of similar shape and make, the larger and heavier bird will almost invariably fly faster than the smaller and lighter one once the former really gets going. It is, of course, true that the peregrine is much quicker in its movements and more agile than the eagle. It is constantly under the necessity of flying at its fastest (which the eagle is not) in order to secure its food; in other words, to use the language of a stalker in discussing this question with me: “The peregrine requires a warm diet, and lives on its prey. The eagle, on the other hand, will eat carrion.” The peregrine is probably quicker off the mark than the eagle, but this does not necessarily mean that he flies more quickly than the eagle once the latter gets going. Stalkers have unusual opportunities of seeing these two birds in flight, and almost all those with whom I have discussed this question believe that on a horizontal flight the peregrine is faster than the eagle. This in my opinion is probably the correct view.
It must not be forgotten that the Northern falcons, or, as they are generally called, the gyrfalcons, are entitled to rank as British birds, although they are rare visitors to these Isles. They are (1) the gyrfalcon or Norwegian variety (Falco gyrfalco), (2) the Iceland falcon (Falco islandus), (3) the Greenland falcon (Falco candicans). The gyrfalcon is a very rare visitor here, two recorded specimens only having been obtained here and one of these is doubtful. The Iceland falcon is a rare visitor also, although identified examples have been obtained here from time to time. The Greenland falcon is an irregular winter and spring visitor, but there are more recorded instances of this species than in the case of the Iceland falcon. The former bird, the prevailing ground colour of which is white, is the most beautiful of all birds of prey. By some authorities it is considered merely a race of the Iceland falcon, which it resembles in size and habits. The eggs of the two birds resemble one another. All these Northern falcons are about the same size and larger than, though very similar in structure to, the peregrine falcon. Speaking generally, the difference in length is about 5 inches, in wing 2 inches. They have been very highly valued in Europe for hawking, and, as would be expected from their superior size and similar structure, are undoubtedly faster than peregrines.
Writing in the Field for March 15, 1923, Major Radclyffe says:[13]
“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.