THE SPEED OF THE PIGEON-POST 91 



they must therefore have flown the distance at a speed 

 of about a mile a minute. He also estimated that the 

 eider-duck flies at the speed of 40 miles an hour, and 

 the wild duck at about 45 miles an hour in sustained 

 flights. One obvious chance of error in his calculation 

 of the speed of the pigeons is the possibility that diges- 

 tion may have been partly arrested while the birds were 

 flying so long a distance. Another statement dealing 

 with the frigate-bird depends on the assumption that it 

 neither flies by night nor sleeps on the water. If this 

 is correct, the distances travelled by these ocean-birds 

 in a single day must amount to as much as 1,800 

 miles, for they have been seen at a distance of more 

 than 900 miles from any coast or island. But no one 

 can prove that they do not fly by night, and the effort- 

 less soaring of these ocean-birds suggests that their 

 power to remain on the wing is certainly not limited to 

 a period of twelve hours. 



It seems contrary to all reasonable conjecture that 

 any bird should make a daily flight of hundreds of 

 miles from its roosting-place. But there are means 

 available for discovering the real rate of flight of the 

 frigate-bird not less accurately than that of the carrier- 

 pigeon. According to the Rev. S. G. Whitmee, the 

 frigate-birds are domesticated by the natives of the 

 Ellice Islands. In 1870 he saw numbers of them 

 sitting about on perches erected for them near the 



