336 BULLETIN 196, UNITED STATES NATIONAL MUSEUM 



feathers, which in adults show wear, since they are not cast after 

 breeding, but held until the early spring moult." 



Food. — Collett, quoted above, states that in Norway in summer 

 the food seems to be wholly taken from the countless myriads of 

 mosquitoes, of which there are at least half a dozen species. All 

 crops examined were crammed with these insects. In a later com- 

 munication (1886) he mentions having on two occasions found the 

 larvae of a Cidaria or other geometrid larva in the stomach, as well 

 as other soft insects. Further exact information is scanty, but 

 Jourdain (1938, vol. 2), summarizing the records of several other 

 observers in addition to Collett, mentions Hymenoptera (larvae of 

 Tenihredo or Lophyrus, ants), Coleoptera, Hemiptera, and other 

 insects. 



Behavior. — All the small leaf-warblers of the Old World have 

 much in common in their behavior, and Eversmann's warbler differs 

 little in this respect from its better-known European relatives. Like 

 them it is a lively and active bird, constantly hovering and flitting 

 about in foliage in search of insects, and sometimes it will hover 

 for a few seconds to pick one off a leaf. It does, however, differ 

 from some allied species in that, at any rate in the breeding season, 

 it keeps principally in the canopy of well-grown trees, in which it 

 chiefly feeds and sings, though it may also be seen at times in lower 

 vegetation. 



Voice. — As more or less marked geographical differences in song 

 and notes, which may or may not coincide with accepted racial differ- 

 ences, are not unknown within the limits of single species of the 

 genus, it cannot be assumed that the song and notes of Eversmann's 

 warbler in Europe are identical with those of the same species in 

 Alaska, though it is evident that they are similar. To an observer 

 familiar with European birds much the best description that can be 

 given of the song of Eversmann's warbler is that it is unmistakably 

 like that of the cirl bunting (Emberiza cirlus), though it is somewhat 

 higher pitched and less hard-sounding. To those not acquainted 

 with that bird the best that can be said is that the song is a little 

 rattling repetition of a single somewhat sibilant note, lasting for 

 approximately three seconds. It is usually, though not invariably, 

 preceded by a clicking tzick uttered one to three times, and when the 

 bird is in full song the fairly regular alternation of the monotonous 

 little song phrases and clicking tzick notes is very characteristic. At 

 such times there is less than one-second interval between the end of 

 a song and the next tzick. The song is generally delivered from 

 among the foliage of trees, though at times lower down, and the bill 

 moves rapidly during its utterance. It may be heard in Lapland 

 from the time of the bird's arrival about mid-June until mid-July 



