Are Our Birds Decreasing or Increasing 



By HENRY OLDYS 



ONE of the features of a meeting of 

 tlie American Ornithologist's Union, 

 held not long ago in Washington, 

 was a discussion of the present relative abun- 

 dance or scarcity of insectivorous birds in 

 the United States. The conclusion reached, 

 to which all the speakers assented, was that 

 the insectivorous birds are now much more 

 numerous than they were in the days of the 

 original settlers. This verdict was based both 

 on theoretical condition and actual obser- 

 vation. In 1898, Dr. W. T. Hornaday of 

 the New York Zoological Park, on the strength 

 of reports secured from manj^ naturaUsts, 

 estimated an average decrease of forty-six per 

 cent in the birds of thirty states and terri- 

 tories in the preceding fifteen years. In 1904 

 Mr. Edward Howe Forbush, under direction 

 of the Massachusetts State Board of Agri- 

 culture, prepared a similar report concerning 

 the birds of Massachusetts, based on opinions 

 obtained from more than two hundred per- 

 sons. The conclusion he reached was that 

 "the smaller buxls in general have not de- 

 creased greatly in Massachusetts as a whole 

 in recent years, except in and near the 

 centers of population." The discrepancy 

 among these various conclusions is palpable, 

 even after making due allowance for the fact 

 that Dr. Hornaday's summing up includes 

 game birds which, as is well known, have 

 undergone a marked decrease. 



Aside from the annual statement of the 

 condition of game animals and game birds, 

 based on reports of sportsmen, which was 

 issued bj' the United States Department of 

 Agriculture for several years, I am not aware 

 of any other attempts to ascertain the extent 

 of numerical changes in our avifauna. The 

 Department of Agriculture has however, put 

 into operation a scheme for securing a count 

 of nesting birds in Imiited areas throughout 

 the country, by which means a more or less 

 reliable basis may be obtained for compari- 

 son with similar coimts on the same areas 

 periodically. Incidentally it might be men- 

 tioned that the government of Germany a 

 few weeks before the beginning of the 

 great war, inaugurated a like count of its 

 birds. 



Somewhat on the same order was a census. 



made under the direction of Dr. S. A. Forbes 

 of the University of Illinois a few years ago, 

 when several assistants made trips across the 

 State, noting all the birds in their paths, while 

 others made similar observations in selected 

 circular areas. Information of this kind, as 

 Dr. Forbes points out, cannot be taken as a 

 proportional basis on which to estimate the 

 total number of birds in a state, but must be 

 regarded merely as a census of the areas under 

 observation, a limitation particularly applica- 

 ble to Illinois with its exceedingly varied 

 topography, but holding true of practically 

 every other state in the Union. 



While all such efforts to determine the 

 relative abundance or scarcity of birds, 

 whether by actual count or by general ob- 

 servation, have a definite value, yet that value 

 must not be overestimated, a caution that 

 would, I doubt not, be seconded by those who 

 have been instrumental in securing such 

 information. Those schemes that involve a 

 count of the birds cover but an msignificant 

 part of the region under investigation, while 

 in the others a very great degree of uncer- 

 tainty is injected by the personal element. 

 The latter difficulty is well set forth by Mr. 

 Forbush in his report. "A conclusion one 

 way or the other," he says, "cannot safely 

 be formed by any individual unaided, except 

 in regard to a limited territory with which he 

 has been famihar for a series of years. Such 

 a conclusion, when formed, is merely an 

 opinion, and the personal equation inevitably 

 comes in to bias it. Some people are natur- 

 ally optimistic, and their reports show it; 

 or they have recently begun to study birds 

 and see more of them now than in former 

 years. Others are pessimistic, or have be- 

 come imbued with the popular beUef that 

 our birds are being rapidly exterminated. 

 Some are elderly people, who do not, perhaps, 

 hear or see so clearly as in their youth, and 

 are not so much afield, and do not notice so 

 many bkds as in their younger days. Some 

 reports come from closely populated regions, 

 where many causes operate to destroy or 

 drive out the birds; others come from more 

 sparsely peopled regions, where the birds and 

 their natural enemies are not so much inter- 

 fered with. These personal or environmental 



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