164 



NORTH AMERICAN FAUNA 73 



1968, Burnett County; 21 November 1950, Polk County). During spring 

 migration, hoary redpolls are observed with common redpoll flocks. Most 

 observations occur in February. Late dates include 4 April 1966, St. Croix 

 County; 6 April 1969, Chisago County; and 12 April 1974, Washington 

 County. 



Winter: Rare and irregular winter resident throughout the Valley. Most 

 winter records consist of observations during the CBC periods, usually 

 15 December to 2 January. The largest number observed (six) was recorded 

 on the Suburban St. Paul CBC 29 December 1973. Considerable debate has 

 been generated concerning the taxonomic status of this bird and the ability 

 of observers to make accurate identification. The most reUable and undoubt- 

 edly correct observations are of banded birds. One individual was banded in 

 Chisago County on 1 March 1970. During the winter finch invasion of 

 1977-78, I banded two hoary redpolls at a feeding station in Hudson, St. 

 Croix County, on 15 February 1978 and 8 March 1978. The latter bird was 

 photographed extensively and copies were deposited with the Wisconsin 

 Society for Ornithology. 



Habitat: Regularly observed with flocks of common redpoll in weedy fields 

 and highway rights-of-way. 



Common Redpoll (Carduelis flammed) 

 Status: Regular migrant and winter resident. 



Migration: Abundant migrant throughout the Valley during periodic inva- 

 sion years, uncommon to rare migrant during other years. Fall migrants 

 arrive 25 October to 10 November (earliest— 12 October 1974, Burnett 

 County). Peak fall migration occurs 15 November to 15 December. Peak 

 spring migration occurs 1-25 March; birds depart from the Central Plain 

 1-10 April and the Northern Highland by 30 April (latest— 30 May 1972, 

 Burnett County). 



Winter: Usually an uncommon winter resident except during invasion years 

 when this species becomes one of the most abundant wintering birds. Christ- 

 mas Bird Count data (Table 4) suggest that the wintering population is 

 fairly well distributed throughout the Valley. The extremely high mean 

 number of common redpolls per party hour on the Solon Springs CBC is 

 skewed upward by a large count during 1977. 



The normal 2-year invasion cycle of this bird is shown by comparing the 

 mean number of redpolls per party hour on CBC's throughout the Valley 

 (Fig. 6). Beginning with the 1970 count year, the winter common redpoll 

 population fits a perfect alternate year invasion schedule. Results from the 

 1977-78 CBC season are considerably higher than other years because the 

 movement of birds that year was one of the largest recorded. The two 

 largest counts on record in the Valley are from the Solon Springs CBC 

 (2,222) and Suburban St. Paul CBC (4,615). The 4,615 is the largest number 

 ever recorded in North America (Monroe 1978). 



Habitat: Agricultural fields, retired cropland that has become heavily over- 



