As mcvry as 100 or more ^lls may "be present in a field at one time. 

 They are very restless and continually mcke short flights. As the ripe 

 "berries are eaten the "bushes are trampled, and many "berries are knocked 

 from the "bushes "by the flapping wings of the "birdis. Feeding gulls may re- 

 main from only a few minutes to more than an hour. 



. : ; METHODS 07 CBDP P5CTEGTI0N 



O-ilfr A i^l Practices 



Pev; fields arc free from sweetfern, alder, birch, "bunch"berry, spiraea, 

 or other v.'eeds. Experiments "by the University of Maine 2/ shov/ that the 

 most effective control of swoetfern results from cutting in July or early 

 August. Since this period coincides viith that of heaviest gull dainage, 

 persons employed to c:ij.t undesirable plants at this time also serve to 

 scare the gulls from fields. Ihc fact that tall weeds har"bor the adults 

 of the "bluc"borry maggot also tends to mal'c this method of protection most 

 do si rah Ic . 



Pickers cratir^ fruit for city markets may also sei^e to frighten 

 marauding gulls. Since uhij operation can "be carried on several v;eeks 

 earlier than picking for canning, and since crated "berries "bring premium 

 prices, 2 or 3 v/ceks preliminary,'' protection may "bo had at little addition- 

 al cost. 



All methods can "be made more effective and economical "by using con- 

 trolled "burning In such way that the "blue'berry tracts will form compact 

 areas. As an exi^mplc, a field of 80 acres might "be eight times o.s long as 

 wide and thus add greatly to the difficulty of protection. If it were 

 square, protection v;ould "be less of a pro"blem. 



Frightening Devices 



The automatic flash gun provides effective protection for an area 

 extending a'bout one-quarter mile in all directions. The apparatus oper- 

 ates "by water dripping on car'bide, thore'by forming an explosive gas, which 

 is ignited "by a pilot "burner. The frequency of explosions is rcg-ulated "by 

 the flow of the water. The device can "be supported "by lasting three poles 

 to form a tripod. Each gun shcnald "be visited at least three times daily — 

 once before 8 a.m., to replenish the carbide and water and sot the device 

 for operation; the second visit later, to insure that operation is satis- 

 f actoiy; o,nd the third at about 6 p.m. , to close the water valve and ex- 

 tinguish the pilot burner. Plash guns usually sell for about $35, 3/ and 

 since 1 pound of carbide is mifficient for about 12 hours' operation, the 

 cost of using them is not great. 



2/ Blueberry Dust Service, mimeographed paper by the Extension 

 Service, University of Klaine. 



3/ A list of dealers in pyrotechnic supplies and other bird-fright- 

 ening devices (5i-1406) can be had from the Bureau of Biological Survey on 

 reque s t . 



- 3 - 



