28 AVIFAUNA COLUMBIANA. 



3.— GENERAL CHARACTERS OF THE AVIFAUNA. 



From the central situation of the District of Columbia, with regard to 

 the northern and southern portions of the United States, together with 

 the variety of surface which it presents, it would be expected to afford 

 the rich and interesting avifauna which it has been found to possess. 

 Although belonging to the Carolinian fauna! area as defined by J. A. 

 Allen, it seems to be, with regard to the migration and breeding of 

 birds, somewhere about a natural dividing line between a northern and 

 southern fauna, so that it is not easy to decide which takes precedence. 

 We are therefore enabled to present a more extensive list of species in- 

 habiting the District than has been determined for any other area of 

 equally restricted extent in eastern North America, excepting a few 

 peculiarly favored by conditions of physical geography. 



Though the numbers of individual birds which are resident through- 

 out the year, and of those which breed here, are considerable, they are 

 few in comparison with the multitudes which regularly pass through on 

 their vernal and autumnal migrations, remaining for a longer or shorter 

 period each season. The spring arrivals, it will be remembered, not 

 only include the migrants proper which neither summer nor winter with 

 us, but also embrace all the breeders which do not remain during the 

 colder portion of the year. It is on this account that for a month or so 

 during the spring and fall — from about the 20th of April to the 20th of 

 May, and from the 1st of September to the middle of October — the col- 

 lector is so amply repaid for his pains, while at other periods ornitholo- 

 gizing is hardly worth the trouble, unless it be for particular species, or 

 for the nests and eggs of the breeders. So numerous are individuals of 

 most of the regular migrants that at the height of "the season" in spring 

 we have collected, in a walk before breakfast, forty or fifty specimens of 

 various species of Warblers, Thrushes, Flycatchers, Finches, and other 

 Passeras. In instance of the number of species which pass through the 

 District on their way north to breed, compared with those which re- 

 main with us during the summer, may be cited the Warblers. Of the 

 twelve or thirteen Bendra'ccc found more or less abundantly in spring 

 and fall, only three are known to breed here; and not one of the four 

 Helminthophilcc is seen in summer. The same might be affirmed of other 

 birds, as various Thrushes, Flycatchers, Finches, Sandpipers, etc. 



Reference to the summary at the end of this treatise will show that 

 the permanent residents (47), the winter visitants (40), and the regular 

 spring and fall migrants (49), are practically the same in number, and 

 about three-fourths as many as the summer visitants. The list of strag- 

 glers is at present the shortest one (40), but will doubtless in time about 

 equal any one of the categories excepting that of the summer residents. 

 The list includes only those species, specimens of which have been 

 actually obtained in the District or its very immediate vicinity. There 



