SUPPRESSION OF PESTS BY BIRDS McATEE. 433 



abundant they destroy tons upon tons of weed seeds, but only rarely 

 are they able even to locally extirpate any of the very prolific plants 

 known as weeds. Dr. Sylvester D. Judd, late of the Biological Sur- 

 vey, gives the following instance 42 of great reduction in the num- 

 bers of weed seeds : 



On one of the Maryland farms visited in 1896 tree sparrows, fox sparrows, 

 white-throated sparrows, song sparrows, and juncos fairly swarmed during the 

 month of December in the briers of the ditches between the cornfields. They 

 came into the open fields to feed on weed seed, and were most active where the 

 smartweed formed a tangle on low ground. Later in the season the place 

 was carefully examined. In a cornfield, near a ditch, the smartweed formed a 

 thicket more than 3 feet high, and the ground beneath was literally black with 

 seeds. Examination showed that these seeds had been cracked open and the 

 meat removed. In a rectangular space of 18 square inches were found 1,130 half 

 seeds and only 2 whole seeds. During the ensuing season no smartweed grew 

 where the sparrows caused this extensive destruction. 



PRACTICAL UTILIZATION OF BIRDS IN SUPPRESSING PESTS. 



Successful utilization of birds in suppressing pests has been made 

 both indoors and out. In the former case birds have been captured 

 and confined in cellars, granaries, and greenhouses, and in the latter, 

 farm practice has been modified to take advantage of beneficial 

 activities of the birds, or the number of birds on certain areas has 

 been increased by introductions, by protection from enemies, by 

 furnishing nesting sites and building materials, and by supplying 

 food when the natural supply is scanty. Experience shows that 

 efforts to attract birds bring their own reward. 



Taking up first the use of birds indoors, we present two accounts 

 of the successful use of owls in destroying rodents. B. H. Warren, 

 formerly State Ornithologist of Pennsylvania, says 43 of the screech 

 owl (Otus asio) : 



Some few years ago an acquaintance of mine placed two of these birds in his 

 cellar which was overrun with mice, and in a few weeks the place was depopu- 

 lated of these little four-footed pests. 



The late Dr. W. L. Ralph who was curator of birds' nests and eggs 

 in the United States National Museum, furnished the following note 

 regarding the barred owl (Strix varia) : 



At the Oneida County Brewery in Utica a subcellar was used for storing large 

 quantities of barley. The rats made serious inroads on this grain and destroyed 

 at least .$800 to $1,000 worth annually. For the purpose of lessening this dam- 

 age cats were placed in the subcellar on several occasions with the result that 

 when the door was opened in the morning they rushed out showing every indi- 

 cation of fear and desperately resisted any attempt made to take them back. 

 At this juncture two boys brought an owl to the Doctor who purchased it with 

 the idea of liberating it so soon as the slightly injured wing healed. In looking 



"Bui. 15. Biol. Surv., pp. 27-28, 1901. 

 43 Birds of Pennsylvania, p. 154, 1890. 



42803°— 22 28 



