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The species of birds doing damage to cultivated blueberries and its extent 

 were determined by means of a questionnaire sent to all known growers. The question- 

 naire summary based on grower observations and tally revealed that songbirds, in- 

 cluding robins, bluejays, chewinks and sparrows; and blackbirds including starlings, 

 grackles and redwing blackbirds were the depredating species. Of all species noted, 

 the robin and the starling are by far the most harmful. 



Through the same questionnaire and personal contact, it was determined that 

 thirty-eight per cent of the total cultivated blueberry crop was lost to birds in 

 1955. In 1956, twenty per cent; in 1957, nineteen per cent; and in 1958, twenty seven 

 per cent of the total cultivated blueberry crop was lost due to depredating birds. 



Simultaneous with the success of accomplishing the first two project objectives 

 was the relative failure in the third - that of finding methods of eliminating or 

 reducing bird damage. To date no completely satisfactory method of bird damage 

 prevention, short of total enclosure, has been found. 



A number of bird damage prevention devices were used by growers and/or myself 

 in the research projects. A carbide exploder is effective only against starlings 

 and grackles and will protect up to 3 acres. They must be cleaned regularly and 

 are objectionable in populous areas. Rope firecrackers are good against starlings 

 and grackles but start fires if used in sawdust or chip culture. Shotguns are per- 

 manent but costly. The following are all ineffective: Rags and papers on strings, 

 scarecrows, balloons, garden hose - to simulate snakes, reflectors and spinners. 



After the elimination of the devices previously mentioned and others, a live 

 Cooper's hawk which is the natural enemy of the robin and starling was tried in the 

 cherry orchard and blueberry planting on University property. The hawk was tethered 

 to a seven foot perch pole and placed about twenty feet from a cherry tree, which 

 was of a different variety and ripening later than the trees surrounding it. The 

 hawk was tethered to the pole for alternating half hour periods. A tally was made 

 of the number and species of birds visiting the tree under both conditions. During 

 five afternoons of such observations, a total of 192 birds were observed feeding 

 while the hawk was absent and only two when it was present. The next step was to 

 substitute a stuffed hawk for the live one. During four afternoons, 154 birds 

 were observed feeding in the absence of the stuffed hawk and only 8 tried to feed 

 when the hawk was present. In the blueberry planting, results were similar with 

 229 birds being tallied while the stuffed hawk was absent and 14 while it was present. 

 These counts were made during 6 afternoons. 



Due to the success with the stuffed hawk, the next step was to construct a 

 hawk decoy which would withstand weathering. Therefore, 12 plastic models were pre- 

 pared at the American Museum of Natural History and hand painted to resemble Cooper's 

 hawks. Used in the cherry orchard, the plastic decoys gave equally as good results 

 as those previously obtained with the live and stuffed hawk. An attempt was made 

 to measure the maximum length of time the decoy hawks would be effective. A decoy 

 on a 22 foot pole was placed in the middle of 5 cherry trees. These trees were in 

 a row and the decoy was placed up through the branches of the middle tree and le ft 

 in this position night and day. The cherries were ripe six days before the robins 

 dared to approach the nearside of the trees adjacent to the tree having the hawk in 

 it. No starlings or grackles entered any of the 5 trees during the 6-day period. 

 Plastic decoys distributed to 4 growers for trial were initially effective but lost 



