REPORT ON BIRD CENSUSES, 1916-1920. 17 



for such land. This, together with the large amount in crops (plowed 

 land), nearly 60 per cent, accounts for the fact that here, in spite 

 of the excess of orchard, the number of birds per acre is less than for 

 the State as a whole or for the Northeastern States. For the entire 

 State the total amount of improved land covered by bird censuses 

 is not far below the normal, though the proportion of orchard is very 

 large, and the woodland also is a little below the percentage given 

 by the official census of 1910. The average bird population for the 

 State agrees very closely with that of the northeastern section for 

 the same years, that for New York State being 122 pairs and for the 

 entire section 126 per 100 acres; at Geneva the average for the three 

 years is just one pair to the acre. 



Viresco, Va. — The longest series of bird counts on file concerns a 

 tract of about 55 acres at Viresco, Va., not far from Washington, 

 and extends over 10 years. This tract has the added interest that 

 the experience gained in making the earlier counts here formed the 

 basis for the 1914 circular of instructions for taking a bird census. 



The land includes 21 acres of woods, 18 of pasture, 5 of land plowed 

 for grain and garden, 3 of brushy hillside, and the remaining 8 acres 

 in trees and brush along a stream that meanders through the place. 

 Most of the cleared land had been cultivated up to a short time before 

 the area first came under observation in 1907, and it was then growing 

 up to brush. At that time the underbrush in the woods had recently 

 been thoroughly cleared, but it has since grown back, and the small 

 trees and brush along the stream have grown considerably. One 

 plot of 3 acres, formerly cultivated, has been allowed to grow wild, 

 and in midsummer about half of it is an almost impenetrable tangle 

 of brush overgrown with catbriar, honeysuckle, and wild grape. 

 Since about 1916 a large part of the chestnut trees have died out 

 of the woods, but the dead trees have been cut each winter, giving 

 a chance for the other species, principally oak and tulip, so that 

 there has been little noticeable thinning of the woods. From 1916 

 to 1918 about 4 acres of pasture were set to orchard, but as yet the 

 trees have not made sufficient growth to alter the character of the 

 land. 



Throughout this period birds have been strictly protected, but 

 the only efforts toward attracting them have been the erection of a 

 small martin house (scorned, however, by the martins, though several 

 times occupied by bluebirds or house wrens), and recently two or 

 three wren houses. No special feeding has been done at any time. 

 The counts on this tract show a steady increase in the number of 

 birds breeding until 1918, when there was a decrease of over 20 per 

 cent; the average of 1916-17 was fully recovered, however, by 1920. 



An excellent example is here furnished of what protection alone 

 can do toward increasing the number of birds nesting on a given 

 area. The growth of the bird population has been greater than 

 that warranted by the increased supply of food and shelter; it seems 

 probable that it has resulted in part, at least, from recognition by the 

 birds of the security of this tract as a nesting place. Unfortunately, it 

 has been impracticable to make counts on the adjacent territory and 

 thereby to ascertain whether any decrease has occurred in its bird 

 life as a result of the increase on the tract surveyed. 

 44125— 23— Bull. 1165 3 



