Next, as to the Alpine swift. This bird is much larger than the common swift--in length 8 inches as compared with 6·75 inches--whilst their wings are 8·45 inches and 6·8 inches respectively, and as the two birds are of the same structure, one would naturally expect that the Alpine swift would be much the faster flier. The flight of the Alpine swift, like that of the blackcock, which is probably the fastest flier amongst game birds with the possible exception of the capercailzie, is very deceptive. Colonel Meinertzhagen, in the article already mentioned, describes some observations from an aeroplane in regard to the flight of a large flock of common swifts feeding at an altitude of 6000 feet over Mosul in Mesopotamia. He describes how they circled round the aeroplane, which was flying at 68 miles an hour, and easily overtook it. In commenting on this case he says: “The case of the Mosul swifts is interesting. The birds were probably not on passage but simply feeding. It is known that swifts travel great distances in search of food and ascend great altitudes. “In the Middle Atlas of Morocco, in the Himalayas, in Crete, and Palestine, 4000 or 5000 feet and 50 miles or so in distance seems nothing to these incomparable fliers. I have had splendid opportunities of observing the Alpine, common, and spine-tailed swifts (_Chaetura_), and it has been a great disappointment to me that I have never been able to get a satisfactory estimate of their rate of flight, as they never continue on a level course. On a small island on the coast of Crete I was recently given a good exhibition of what an Alpine swift can do. I was watching some of these birds feeding round cliffs in which several pairs of Eleonora’s falcons were about to breed. Now, this delightful falcon is no mean flier, and as these swifts passed their cliff, the falcons would come out against them like rockets. The swifts would accelerate and would seem to be out of sight before the falcons were well on their way. So confident were the swifts in their superior speed, that every time they circled round the island they never failed to ‘draw’ the falcons, and seemed to be playing with them. I may add that these same falcons have little difficulty in overhauling and striking a rock-pigeon--itself no mean performer. I have also seen on record the case of falcons and swifts somewhere in India, where the former failed time after time to come up with his quarry. I, unfortunately, cannot trace the reference. “I hesitate even to guess at the speed to which a swift can attain when the necessity arises, but the main point is that this, the fastest of birds, can increase his feeding speed of, say, 70 miles per hour, to a velocity which must exceed 100 miles per hour.”