540 U-S. NATIONAL MUSEUM BULLETIN 23 7 pabt i 



observations confirm it under favorable conditions, such as in a 

 natural amphitheatre. 



Ridgway (1889), referring to a pair of caged birds kept by Dr. 

 Brewer, says: "They were in full song, and both the male and female 

 were quite good singers. Their songs were irregular and varied, but 

 sweet and musical." 



G. M. Sutton, quoted by W. E. C. Todd (1940), encountered birds 

 of this species wintering in Pennsylvania. Sutton says: "While the 

 birds were feeding, there was a constant chattering going on; the notes 

 were either double- or triple-syllabled and very sweet and musical, 

 although not clear. Now and then could be heard a louder, somewhat 

 clearer note, seeming to come from another species of bird; but the 

 chances are that it was another note of one of the crossbills." 



L. Griscom (1923), also discussing birds out of their normal breeding 

 habitat, states that wintering birds have as their most common note 

 "a rattle or chatter very like the Redpoll, but much louder, more 

 prolonged, and less hoarse. Another common note is a sweet, 

 whistled twee, sometimes given in couplets, which is very like the 

 familiar Goldfinch call, but it lacks the rising inflection at the end. 

 When a flock is quietly feeding, there is also a note which sounds like 

 a Junco singing very badly and hoarsely." I have heard the air full 

 of these sweet whistled twees — to me not in the least suggestive of a 

 goldfinch — and looked up to see a flock of 50 to 100 birds fly speedily 

 overhead in a mass formation. All notes seemed to be on the same 

 pitch — a symphonic undertone appearing again throughout the song 

 itself. 



Field marks. — The male white-winged crossbill viewed face on 

 might easily be mistaken for a purple finch, which is of similar size 

 and frequently occurs in the same territory summer or winter. The 

 two white wing-bars on the black wing, however, are diagnostic. 

 Only at close range under favorable conditions can the crossed bill 

 be seen. The somewhat similar pine grosbeak is larger, approaching 

 the size of a robin, and lacks the crossed bill. As compared with the 

 red crossbill, the red of the male white-winged crossbill tends to be a 

 sparkling rosy color whereas that of the red crossbill is more nearly 

 a flat brick red. There is much variation in the latter, however, and 

 L. Griscom (1937) points out that the form benti is actually rosy also. 

 Absence of the white wing-bars is characteristic in females and 

 immatures as well as in male red crossbills in North America. 



Female and immature white-winged crossbills are a blended com- 

 position of olive and light brown or gray, but show the dark wing with 

 the two white patches. From this plmnage, the amount of red in 

 the case of molting young males progresses until the full adult stage 

 is reached. 



