24 MICHIGAN BIRD LIFE. 



level, hence its resistance to the passage of a bird at that height would be 

 lessened one-half. It does not follow, however, that therefore a bird at a 

 height of three and one-half miles can fly at double its speed at the surface 

 without increased effort. A moment's thought will' show how preposterous 

 is such a claim. The very tenuity of the air, which lessens by one-half the 

 resistance to the forward motion of the bird, must lessen in exactly the same 

 proportion the supporting power of the air and its resistance to the wing- 

 strokes, which alone give the bird headway. We may dismiss as absurd 

 the claim that birds may double their speed by flying in rarified air. 



After careful search I have been unable to find a single instance in which 

 the speed of any bird has been shown by actual measurement to i-each over 

 100 miles per hour. There are plenty of guesses, a few bold but unsupported 

 assertions, and a number of more or less probable estimates. 



The figures furnished by pigeon fanciers give us some idea of the possi- 

 bilities of the homing pigeon, so often miscalled the ''carrier pigeon." These 

 records of course give only the average speeds, but these are certainly sug- 

 gestive. The greatest velocity of which I find mention is eighty miles an 

 hour, at which rate a homing pigeon is said to have covered 114 miles in 

 1892. I am vmable, however, to verify this statement. Another, and more 

 likely record, is seventy-one miles an hour for a distance of eighty-two miles, 

 while the average velocities of the winners in a large number of contests 

 do not exceed forty miles an hour. In 1883 the best time made in eighteen 

 races was 208 miles at the rate of fifty-five miles per hour. Over longer dis- 

 tances the velocity is very much less, and in the longest flight of which I can 

 find a record, that of a pigeon which flew from Pensacola, Florida, to Fall 

 River, Mass., fifteen and one-half days were consumed in covering the 1,183 

 miles, the average speed being seventy-six miles per day. 



In experiments tried with swallows in France it is claimed that one swallow 

 flew 160 English miles in ninety minutes, giving a velocity of 107 miles an 

 hour, but this record is open to serious question. 



Wild geese, and especially wild ducks, have been credited with a speed of 

 nearly 100 miles an hour, yet in two cases where it was possible to measure 

 the speed of flocks passing a given point, it was found that the geese flew at 

 the rate of but 44.3 miles per hour, and the ducks at approximately forty- 

 eight miles per hour, and in neither case did the height exceed 1,000 feet. 

 These measurements were made at the Blue Hill JMeteorological Observatory 

 at Milton, Mass., by trained observers with the instruments used daily in 

 determining the velocity of clouds.* In 1893 Dr. Hubert L. Clark noted 

 two Buffle-head ducks flying along the Potomac River parallel with a train 

 on which he was a passenger. The train was found to have a speed of about 

 thirty-seven miles an hour, and the ducks were unable to keep up with it. 



Heinrich Gatke's statement that the Golden Plover flies at the rate of over 

 200 miles an hour is based on data which he misunderstood or misrepresented. 

 He states positively that the Golden Plover migrates in autumn from Labrador 

 to Brazil, over the Atlantic in one iininterrwpted flight of 3,000 miles! He 

 further assumes (without explanation) that fifteen hours is the longest time 

 any bird could remain on the wing without food, and hence that the above 

 flight of 3,000 miles is made in fifteen hours, at an average speed of "212 

 geographical miles an hour, "f He does not explain exactly why this speed 

 is 212 miles instead of precisely 200 miles per hour, as we should figure it, 

 but we need not quibble about a paltry dozen miles in the case of birds moving 



♦Science, New Series, V, pp. 26, 585-5S6. 



tHelieoland as an Ornitliological Observatory, Edinburgh, 1895. 



