It seems that there is a lot of research to be done on the common redpoll, this scientist found too many notes in the reference material that suggested there was not enough or no proof on certain aspects of the common redpoll. What he did find was that the information in one was markedly different than another. As a result he cross referenced his finding and came up with as best an explanation as he could find, which amounted to the most recent. He also made some speculations that should be easily recognized by the addition of question marks or parenthesis. The citations given in the text of this document covers all of the information previous to the citation (from citation to citation if you will), of which are ponderously worded with a vernacular that is unique to this scientist alone.
The common redpoll (Carduelis flammea) is a very small finch with a conical bill; ranging in size from 12-14 cm in length and 11-20 g in mass (Knox and Lowther 2000). The common redpoll's name is derived from the noticeable red spot located at the crown of both sexes (female spots are duller in comparison). Often confused with the hoary redpoll, the common redpoll has broad brownish colored streaks that flow along the flanks, whereas the hoary redpoll (Carduelis hornemanni) has fine streaking along the flanks. Common redpolls also have a streaked rump and streaked undertail coverts; the hoary redpoll lacks streaks on both the rump and undertail. Another distinction between the two is that the male common redpoll has a red or deep pink coloration upon the breast where the male hoary redpoll has a lighter tinged pink coloration. Aside from the streaked coverts and rump the female redpolls greatest distinction is that the common redpoll is generally darker in coloration than the hoary redpoll (Sibley 2003). During winter and fall molting the coloration turns lighter or buffer except the streaking which darkens in color, wings have a slightly greater extent of pale or whitish edges, and wingbars become much more prominent (Clement 1993).
Common redpolls breed in the sparsely human populated northern boreal and taiga regions of both old and new world arctic and spend winter in the Upper US, Europe, and Northern China only in alternating irruption years. The irruption is due to failures in seed-crop production among spruce and birch which causes the birds to forage further south. One common redpoll was banded in Belgium during winter, it was recovered 8345 km east in Heilongjiang Province, China. Of note is the human influenced displacement of the common redpoll; in the year 1867 AD, 14 individuals were released successfully from Canterbury England to New Zealand, with an additional 50 in 1872, 120 in 1873, and 120 in 1875 (Knox and Lowther 2000), the success of the common redpoll is prolific enough that it is considered one of the commonest birds of New Zealand and a pest because of their penchant of destroying the blossoms of native fruit trees (Newton 1973).
Because of the common redpolls habitat there has been no information to estimate total numbers of its population in North America; however, population genetic models suggest that the effective population size for the species is at about two-hundred thousand in North America. Christmas bird counts of a fraction of a percentage of the species winter range done in 1986-1987 in North America reported around ninety-thousand individuals. Total European populations are estimated at around 1.2-2.4 million, and Russian population is at around 10-100 million individuals (Knox and Lowther 2000). The status of the common redpoll is common or locally common (Clement 1993).
Common redpolls are mostly monogamous; there was one case of sequential polyandry documented: first egg of second nest with new male one day after young from first nest fledged (Seutin et al. 1991). Other pairs persisted for 2-3 other nesting attempts, no evidence that bonds lasted beyond one season. The display of the male common redpoll is an aerial show that is often time accompanied by other males. When a male has chosen a female he will hover above her waiting for her acquiescence; her acceptance of him is a crouching display with slightly trembling spread wings and a raised tail. After copulation a female will sit and preen while the male flies off singing. Mating season is usually from late-May to mid-June, two broods are common; there have been reports of as many as three broods per season. The male takes care of the fledglings (around 5-6 days old) from the first brood while the female lays a second clutch. During her brood care the male will feed the female and chicks by passing food to her where she feeds the chicks with the proffered food. The clutch size is around four to seven eggs, the young are born altricial (nearly naked and helpless) and nidicolous (confined to the nest). Their eyes begin to open at three days and fully open on the fourth. Primary feathers begin to emerge at four days. There have been instances of male helpers at each of 2 nests; possibly evidence of polyandry? Young leave nest at 11-15 days of age. The young are reportedly independent of adult care at 26 days of age. Unfortunately there is little information beyond what is given here about the stages of life (Knox and Lowther 2000).
The common redpoll feeds primarily on small seeds (mostly birch and alder) and arthropods (spiders, caterpillars, flies and the like). Their diet consists of around 70% seed and 30% bug, with a small portion of grit. They eat around 31-42% of total body mass each day depending upon the season or the amount of forage. What a common redpoll lacks in size they more than make up for in aerial dexterity and vigor this is evident in their foraging habits: Common redpolls can suspend themselves upside down and steady catkins with one foot while expertly retrieving seeds or they have been known to aggressively shake catkins from birches then pick up the seeds dropped upon the ground (probably why the fruit blossoms have suffered so terribly in New Zealand). Common redpolls have been known to frequent feeders, however, they will only eat millet seeds, they will tediously pick through the feeder just for millet and if there is none to be found then they will ignore the rest (Knox and Lowther 2000).
Knox, Alan G. Lowther, Peter E. The Birds of North America. no. 543. 2000.
Clement, Peter. Finches and Sparrows. 1993. Princeton University Press. Princeton,
Newton, I. Finches 1973. Taplinger Publishing Co., Inc. New York, New York.
Sibley, David A. The Sibley Field Guide to Birds of Western North America. 2003.
Random House Inc., New York.