Speed at which Birds Travel 339 



scarcely passing beyond the Gulf States, and the struggle 

 was temporarily terminated about March I, by a 'second 

 winter,' which recongealed the open water and sent the 



Ducks back to winter quarters At Saint Louis the 



thaw began on March 9, and was fairly under way on the 

 10th. Ducks began to return, and the first real advance 

 since February I was made on March 10. By the 12th 

 and 13th they had moved to Lat. 41 ° 10' in Illinois, and 

 41 ° 42' in Iowa. The movement rapidly gained headway. 

 The Ducks had been held back so much later than usual, 

 that as soon as a movement was possible, it was partici- 

 pated in by the whole family. March 15 and 16 were great 

 days for migration, aided by a warm south wind. The 

 movement was peculiar in that the bulk was almost abreast 



of the van From this time, each day was marked by 



a record of advance " 



In the same careful manner is recorded the migration of 

 many other birds, and that of the Thrushes, Warblers, and 

 Swallows is very interesting. With regard to the speed at 

 which birds travel, Dr. Cooke credits the Purple Martin 

 {Progne purpurea) with a rate of 120 miles for every night 

 of movement. On this rate of speed much speculation has 

 existed, but most of it is guess-work, and it is a fact almost 

 incapable of proof. From the statistics compiled for his 

 Report, the above-named observer came to the conclusion 

 that the speed of migration is different in some species to 

 others, and while he credits some with a journey of only 

 twelve miles a day, others attain a distance of from twenty- 

 three to twenty-eight miles. These are of course Land-birds. 

 Geese, he thinks, may travel from 300 to 600 miles at a 

 single flight. These figures are moderate enough, and if we 

 consider that Thrushes and Warblers are likely to feed as 

 they go, a distance of a dozen or twenty miles a day is 

 ample progress, and it is scarcely possible that the Arctic 

 Blue-throat (Cyanecula suecicd) can leave Africa at dusk 



