358 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



tliem and llio clumii«2;c done amounted to about 10 per cent of the 

 crop in the case of sour cherries and to 75 and even 100 per cent of 

 sweet cherries. An order was therefore issued i)ermitting the killing 

 of robins from June 1 to July 15, guarded by numerous restrictions 

 designed to prevent abuse of the permit, especially the killing of 

 birds other than robins. 



FISH-EATING BIRDS. 



Partly from a general study of the economic relations of fish- 

 eating birds and partly from a special investigation of the subject 

 in Minnesota, Wisconsin, and Michigan, it became evident that cer- 

 tain fish-eating birds are a pronounced nuisance about fish hatcheries. 

 The peculiar conditions at hatcheries that make the visits of fish- 

 eating birds so destructive are that all fishes on the premises are of 

 valuable kinds, and as they are confined in great numbers in shallow 

 pools the}' fall easy prey to such birds. For these reasons birds which 

 may be nearly harmless under natural conditions, preying chiefly 

 on worthless fishes, the valuable kinds being in the minority in their 

 habitat, become at fish hatcheries exclusively and often highly in- 

 jurious. The birds which most often resort to fish hatcheries and 

 which are named in an order of the Secretary of Agriculture per- 

 mitting aggressive action against them at such places are the grebes, 

 loons, gulls, terns, mergansers, the bittern, great blue, little blue, and 

 green herons, and the black-crowned night heron. 



One of these groups of birds, the mergansers, or fish ducks, have 

 been accused of doing much damage in trout streams, particularly in 

 Michigan. From three different investigations of the matter it has 

 been learned that while mergansers occur in small numbers on most 

 Michigan streams, they are very fond of trout and occasionally in 

 severe winters concentrate on certain trout streams in such numbers 

 that great destruction of these valuable fish must ensue. A permit, 

 therefore, has been issued authorizing employees of the game, fish, 

 and forest-fire department of the State of Michigan to control the 

 number of mergansers. 



DAMAGE BY OTHEK MIGKATOUY WILD FOWL. 



In Back Baj^, Va., and Currituck Sound, N. C, swans have in- 

 creased considerably in numbers and much more in fearlessness as a 

 result of the long term of protection they have enjoyed. They have 

 changed their habits b}^ coming to feed in small ponds in the marshes, 

 a thing they rarely, if ever, did during the period in which they were 

 hunted. The small ponds they visit are the chief attraction for the 

 wild ducks on the premises of the various ducking clubs of the region, 

 but the feeding operations of the swans, which may not be shot, soon 

 deplete the stock of duck food in the ponds and render them unat- 

 tractive to the ducks, the game chiefly sought by the clubs. Damage 

 to shooting properties undoubtedly occurs, but owing to local compli- 

 cations which would result in remedial measures being misunder- 

 stood, and, further, to the very important fact that the region where 

 damage occurs is the winter home of practically all the swans of 

 eastern Xorth America, and that preservation of the birds absolutely 

 depends upon the treatment they receive there, it has thus far been 

 deemed inexpedient to authorize control measures. 



