Vfliile screening with viire mesh is the surest way of gaining complete 

 protection, this method is sometimes found impracticable because- of the cost 

 or of physical obstacles to its use. . ■• : : 



Earl E. Hoover, biologist of . the Nevj Hamshire. I)ispattraent of Fish 

 and Game, recently reported that the iimerican bittern h&d caused considerable 

 trouble in a pool at one of the hatcheries. The hatchery men noted 

 that- the bitterns -could not stand and feed in very, deep water and that when 

 cor:iing to feed, they would always' alight on land: or in very shallow water 

 and then wade out to places where the fish were concentrated. He stated 

 that the depredations had been stopped by the following means: A strip of 

 poultry netting vvas erected around' the entire pool, placed in the shallow 

 water a few inches from the margin, so that it projected a foot above the 

 surface (18 inches xvould probably be more effective) . The bitterns were 

 found invariably?- to alight on the landward side of the fence and walk back 

 and forth along the shore- trying to find an opening. VJliile this method may 

 not be 'entirely effective i'or bitterns in other sections, it is worthy of 

 experimentation when depredations are known to be caused by those birds. 



'■■ - The Nevada Eish and Game Commission reported that Howard S, Doyle 

 had 'been successful in excluding great blue herons from a 2-acre hatchery 

 pond by 'stringing small telephone wires across it i,n one direction (no cross 

 wires were used). The xjires 'Neve placed about 2 feet apart and 2 feet above 

 the surface of the water. The superintendent of the hatchery stated that 

 the herons still fly over the pond but the wires frighten them away and 

 shooting is no longer necessary, although formerly a guard had been stationed 

 near the pond much of the time to shoot them. 



Open reservoirs in some of the jiorthsastern States have been effec- 

 tively protected against concentrations of gulls by stringing wires about 

 4 feet apart across the vjidth and length of the pools at a height of 4 or 5 

 feet ■ above the surface of the water ,, thus creating a covering of 4-foot 

 squares over the reservoir,- The size of these squares can be increased or 

 decreased, depending on the particular type of birds involved, }i[ove 

 specific details are contained in the Leaflet (No. 120) above .referred to, 



. Use of 't!raps 



It has long been a common practice of fish culturists to use pole traps 

 around hatchery ponds in the control of certain' fish-eating birds, particu- 

 larly the kingfisher. This method, as ordinarily practiced, is unnecessarily 

 cruel and, -as it usually results in the. indiscriminate destruction of a large 

 number of valuable song or insectivorous birds, it should be avoided unless 

 all other methods have proved unsatisfactory, ViJhen perching sites used by 

 kingfi'shers are. .scarce- around hatchery ponds those remaining can frequently 

 be eliminated by -covering them '.'ith small boards through which several long 

 nails have been driven, the sharp 'points projecting upward about 3 inches. 



Frightening devices in great variety have been used to. forestall bird 

 damage. Some of these can be adapted for use around hatchery ponds or- along 

 sections of trout streams where destruction of fishes by. birds has occurred, 

 A few -of those that are most worthy of trial in such situations are described 

 below, • 



■■■ : ...:. - 13 -- 



