100 The Wilson Bulletin — No. GO. 



ALEXANDER. \\lLSON IN I51RD CENSUS WORK. 



BY FRANK L. BURNS. 



The many-sided Akxauder Wilson has puhhshed, in the 

 preface of Vol. IV, pp. \'-X of his American Ornithology, 

 dated September 13, 1811, probably the earliest bird census 

 of this country. As it is found in only the earlier editions 

 and consequently is inaccessible to most of my readers, I 

 quote in full : 



"To the philosopher, as well as the naturalist, and to every 

 man of feeling, the names, migration, and immense multitudes 

 of birds in this country, are subjects of interesting and in- 

 structive curiosity. From the twenty-first day of March to 

 the first of May, it might with truth be asserted, that at least 

 one hundred^ million of birds enter Pennsylvania from the 

 south ; part on their way farther north, and part to reside 

 during the season. This is no extravagant computation, 

 since it is allowing only about four hundred individuals to 

 each square mile ; though even those resident for the summer 

 would probably average many more. Our forests at that sea- 

 son are everywhere stored with them ; and even the most 

 gloomy swamps and morasses swarm with their respective 

 feathered tenants. In Mr. Bartram's Botanic garden, and the 

 adjoining buildings, comprehending an extent of little more 

 than eight acres, the Author has ascertained, during his 

 present summer residence there, that not less than fiftv-one 

 pairs of birds took up their abode, and built their nests within 

 that space. Almost all of these arrived between the above 

 periods, besides multitudes of passengers. Every morning 

 (for evening, night and morning seem their favorite hours of 

 passage) some new strangers were heard or seen flitting 

 through the arbors, until one general concert seemed to pre- 

 vail from every part of the garden." 



^^'ilson's figures are apparently based upon the assumption 

 that the vernal migration progresses as a rule directly north- 

 ward. The 250,000 square miles of territory required in his 

 computation would extend from the southern limits of Penn- 



