PINE SISKIN 429 



northern forests where one can say, 'We will find the pine siskin 

 here this year.' " 



M. H. Swenk (1929), in his study of this species in Nebraska, 

 correlated breeding records with temperatures of the months March, 

 April, and May. If the mean temperatures for April were subnormal, 

 the siskins might remain and breed; the same might happen if 

 supernormal April temperatures were followed by subnormal May 

 temperatures. Nebraska is, of course, outside the area where the 

 siskin ordinarily may be expected to breed. 



Usually the birds are numerous — often abundant — in areas where 

 food is plentiful. The flocks contain both sexes. Scattered flocks 

 tend to join, forming larger ones. By late January of most years, 

 in localities all across the continent, the thin lispy calls of the siskin 

 are augmented by a warbled song. At this time the flocks break up 

 into smaller ones, then into groups of three to five birds, then into 

 pairs. 



There is considerable fighting and chasing when the flocks start 

 to disintegrate. At Rutherglen, Ontario, Mrs. Lawrence notes: 

 "In the midst of all this sweet singing, two birds swing into the air 

 in an extensive 'cloud chase', their movements tightly synchronized 

 as they alternate in the roles of pursuer and pursued." 



Perhaps anticipatory to courtship- and nest-feeding is a performance 

 observed in late April in Everett, Wash,, by M. R. Thayer (1911): 

 "Our attention was called to three birds on a [trellisj cross-bar 

 about seven feet from where we stood. Two were close together 

 and the third a little apart, and all three were opening and closing 

 their bills, stretching them wide as if yawning and closing them with 

 a snap. Before we had time to consider what it might mean, the 

 two turned toward each other and touched their bills in a 

 most lover-like manner. They were quiet a moment, then one 

 opened his bill wide again and they both flew away followed by the 

 thu-d * * *." 



Courtship feeding begins while the birds are still in flocks or 

 small groups. On Feb. 5, 1948, at Rutherglen, Ontario, Mrs. 

 Lawrence (MS.) noted: "The female sat on a twig. Presently the 

 male alighted on the same twig, hopped up to her and offered her a 

 small particle, of what I could not see. She crouched and, with 

 trembling wings, accepted the offering." 



The birds are still in flocks or groups when courtship flight with 

 song reaches its fullest development. Two paragraphs from Mrs. 

 Lawrence's notes describe it well: "With a beam of sun-shine 

 illuminating his golden flashes, the male rose into the air with 

 tail spread wide and wings in a blur of rapid motion. To the accom- 

 paniment of a flight song which seemed to express far more musical 



