NATURAL SCIENCES OP PHILADELPHIA. 23 



developed sexual organs, from the beginning of April ; while the 

 sharp-tailed remained in moult through the same month. This, 

 of itself, is a good indication of some notable difference in the 

 time, and probably the places, of breeding. I do not think that 

 any of the sharp-tailed finches breed hereabouts ; and it was not 

 until Ma}'^, when they appeared to be about leaving, that I found 

 any with excited organs, or in perfect plumage. At that date 

 the seasides were mating and nesting, if not already incubating. 

 In the fall, when both species are again together, it is only during 

 a part of the season that they are found in equal numbers. This 

 is during the warm days of October, when they loiter in troops 

 about the bushes around the edges of the marsh, as well as 

 among the reeds. Previously, in September, there are few of the 

 sharp-tailed to be seen ; and on entering the marshes in Novem- 

 ber, the seasides will be found scarce or altogether wanting, 

 while the former are still abundant. These observations, which I 

 made very carefull}^, are mutually explanatory, and point to the 

 fact that these two species, so closely allied, so often found to- 

 gether, and so commonly spoken of in identical terms, have 

 really a different range of habitat (one being more northerly 

 than the other), migrate independently of each other, moult at 

 separate seasons, and breed more or less apart. 



Ammodromiis maritimus. 



More numerous, on an average, than the last, and more truly 

 characteristic of the locality, as it breeds here in great numbers. 

 In April it retires from the interior of the marsh, to place its 

 nest among the bordering bushes, a little above high-water mark. 

 It begins to sing when mating, and is afterwards, during the in- 

 cubating, particularly earnest and persevering about it. Each 

 pair usually claims some particular copse, and the male has his 

 favorite singing post, to which he continually resorts. The 

 simple song is something like that of the yellow-winged sparrow, 

 beginning with a few slow notes, then a rapid trill, finally slurred 

 till it sounds like the noise made by some of the grasshoppers. 

 The nest and eggs are now well known. The young in September 

 are somewhat differently streaked from the adults, and appear to 

 constitute Audubon's A. macgillivrayi. 



The comparison that has been drawn between the actions of 

 the Ammodromi and of Sandpipers seems somewhat forced, and 



18T1.] 



