Henshaw on Causes affecting the. Decrease of Birds. 1 93 



The past season has been unusually fruitful in casualites of the 

 sort referred to, and during early May storms in New England 

 carried oft* great- numbers of Swallows which, from their ten- 

 der organization and inability to procure food in tempestuous 

 weather, easily succumb to the effects of long, cold storms. 

 Even as far south as Washington, and as late as June, a rain 

 storm accompanied by hail killed large numbers of as hardy a 

 bird as the English Sparrow, other species suffering in due pro- 

 portion. Of the local effects of a storm, however, the best 

 example I know of is the case of the extermination of the Pur- 

 ple Martins in Cambridge and near vicinity years ago during 

 a cold storm which caught the birds a day or two after their 

 arrival from the south.* This instance is of peculiar interest, 

 insomuch as the Martins, although affected only within a small 

 area and remaining abundant outside of it, have never reoccupied 

 the lost ground ; whether from a failure to increase sufficiently to 

 colonize it, or from inability to make headway against the Swal- 

 lows and Wrens, usurpers of their ancestral seats, is uncertain. 



That the causes above named play an important part in the 

 reduction of birds is certain, but with the exception of the last 

 they act in so regular and systematic a manner, or are too 

 unimportant in their effects, to be accepted as explaining the 

 marked decrease which many species undergo in the inter- 

 val between their departure from and their return to their 

 northern homes. We have now to consider another class of facts 

 in which storms appear as the destructive agents but in a totally 

 different way from those hitherto noticed. 



It has long been well known that in foggy and tempestuous 

 weather, at all seasons of the year, but particularly during the 

 migrations, birds are killed in great numbers by being dashed 

 against the light-houses. f 



* Facts of this sort, which may be indefinitely multiplied, are of themselves a 

 sufficient refutation of the common superstition that birds are endowed with some 

 mysterious faculty by means of which they are enabled to foretell the weather in ad- 

 vance, and time their movements accordingly. The ill-timed arrival of migrants may 

 be studied to peculiar advantage on the shores of the Great Lakes, where the sudden 

 northers of early spring often check the migrations and fill the shrubbery of the 

 southern shores with great numbers of northern bound birds. The much quoted 

 adage of the " early bird," with its appropriate lesson, fails of application most signally 

 in the case of our migrants, whose forwardness not rarely bears bitter fruit in the 

 death of thousands. 



t For interesting data on this see Mr. J. A. Allen in Bulletin Nuttall Ornithological 

 Club, Vol. V, pp. 131-138. July, 1880. 



