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THE AMERICAN MUSEUM JOURNAL 



differences tend to produce contradictory 

 reports." 



Still less can the figures thus secured be 

 used as sound statistics when no attempt is 

 made to separate birds by groups according 

 to the different influences at work upon them. 

 Thus, to class the wild turkey, which early 

 colonists in New England were accustomed 

 to shoot from the doors of their dwellings,-but 

 which is now practically confined to a few 

 favored localities in the southern half of the 

 United States, with the English sparrow, 

 whose phenomenal increase is within the 

 knowledge of all, and to report that the wild 

 turkej- and English sparrow on the average 

 have neither increased nor decreased, would 

 palpably be an unsatisfactory conclusion. 

 Yet while not so striking, other groupings are 

 equally inconclusive. Birds that habitually 

 nest in swamps must decrease as swamps are 

 drained unless thej' alter their habits to 

 conform to the changed conditions, which is 

 not evident; while birds that build about 

 homesteads are likely to increase as home- 

 steads multiply. It will readily be under- 

 stood that to average these two distinct 

 classes will produce results that can have 

 little, if any, scientific value. 



To attain a high degree of accuracy all 

 investigations of relative numbers of birds 

 should consider each species separately and 

 should give due weight to all factors that may 

 enter into the problem; even then allowance 

 must be made for error — • human bias, in- 

 complete returns and overlooked factors. 

 The complexity of the inquiry may be illus- 

 trated by one or two examples. Bewick's 

 WTen is a bird that nests freelj' around the 

 homestead; hence it would seem that in- 

 creasing settlement of the country should 

 cause it to increase. But the same influence 

 tends to increase the aggressive house wren, 

 which is inimical to Bewick's wren and re- 

 duces its numbers by breaking up its nests 

 and driving it away from the homestead. 

 Again, the destruction of hawks and owls 

 would appear to be of direct benefit to the 

 crow blackbird by reducing its enemies; 

 but hawks and owls keep down crows, which 

 rob the ne.sts of blackbirds and of course 

 would do so with greater frequency in the 

 growing decrease of hawks and owls. So, 

 too, the spread of the gospel of bird protec- 

 tion, with its repressive influence on de- 

 struction of birds by boys, on the shooting 

 of the larger non-game birds by men for sport, 



on the collecting of birds for the cage or for 

 the millinery market, and the success of 

 this doctrine in its advocacy of providing 

 food, shelter and nesting places for birds, 

 ought, one might think, to cause a general 

 increase of all non-game birds. But the 

 changed conditions thus brought about are 

 also beneficial to such birds as jays, crow 

 blackbirds and others of the larger birds that 

 have the habit of feeding on the eggs and 

 young of the smaller; other things being 

 equal, these tend to increase disproportion- 

 ately and in a growing ratio. (This rule 

 however is subject to special exceptions.) It 

 has been found also that the substitution of 

 the camera for the gun may work for actual 

 net decrease of birds in regions occupied by 

 foxes, which are reported to follow the scent 

 of the nature photographer and clean out oc- 

 cupants of the nests he photographs. A 

 like habit of foxes in England has caused 

 keepers on game preserves to be chary of 

 visiting nests of pheasants and partridges. 



These and many more agencies of increase 

 or decrease must be given due weight in any 

 adequate investigation. Certain indications 

 must also be noted as fairly reliable. Thus, 

 the mocking bird in the East and the cardi- 

 nal in the Middle West appear to be extend- 

 ing their ranges northward. From this we 

 may tentatively conclude that these species 

 are increasing, especially since, through the 

 abolition of the wide practice of trapping 

 them for cage and aviary, an increase might 

 naturally be expected. The growing re- 

 striction of the shooting of robins in the South 

 should cause an increase of this species; 

 this expectation is apparentlj' confirmed by 

 the much greater abundance of nesting and 

 wintering robins near Washington City, and 

 doubtless elsewhere on the borders of their 

 range. So, on the other hand, the shrinkage 

 in the natural range of the bobwhite and the 

 prairie chicken points to a decrease of these 

 mu('h-hunted game birds. 



It would seem desirable that inquiries into 

 relative scarcity or abundance of birds, should 

 consider them species by .species, that trust- 

 wort hj* facts may be deduced. An investiga- 

 tion of this kind, which might well be under- 

 taken by the United States Department of 

 Agriculture or the National Association of 

 Audubon Societies, would supply information 

 that might serve as a satisfactory basis for 

 rational and intelligent measures for the pro- 

 tection and proper utilization of birds. 



