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The following is rather technical, and is taken from the Birds of North America Online, a website worth subscribing to. Note that repeated attempts to demonstrate hybridization have failed. As I recall, mtDNA differences between Darwin's Finches are essentially nil, though I am not certain of this. Hoary Redpoll closely related to Common Redpoll and sometimes treated as conspecific under latter name (e.g., Salomonsen 1928, 1951; Williamson 1961; Troy 1985) or as separate species (e.g., Baldwin 1968, Godfrey 1986). Extensive sympatry of C. h. exilipeswith nominate C. f. flammea much debated, less so equally interesting overlap of C. h. hornemanni and C. f. rostrata . In areas of sympatry, birds range in plumage from typical pale of Hoary Redpoll to typical dark of Common Redpoll, which has led to frequent unsubstantiated claims that intermediates are hybrids (e.g., Brooks 1968, Jehl and Smith 1970). Plumage of both Hoary and Common redpoll varies and dark Hoary (often young or female) can be mistaken for pale (often older male) Common Redpoll. Little or no direct evidence of hybridization. Differences between Hoary and Common redpolls in time of arrival and departure at breeding grounds, relative abundance from year to year, habitats, diets, calls, physiology, behavior, size, and appearance suggest best treated as separate species (Molau 1985; Knox 1988; Herremans 1990; Seutin et al. 1992, 1993). Suggestion that C. h. exilipes and nominate C. h. hornemanni are northern representatives of, and most closely related to, nominate C. f. flammea and C. f. rostrata, respectively (Molau 1985), and that these 4 taxa be treated as separate species (Herremans 1990), requires further support. See also Brooks 1917 . C. f. flammea arrives on breeding grounds later than C. h. exilipes and leaves earlier in autumn. The 2 forms sometimes nest in different habitats but may forage in same areas. Some authors have reported differences in diets. The 2 taxa differ in calls, physiology, behavior (e.g., migration), size, and appearance. Abundance of the 2 forms in any 1 breeding place varies independently from year to year. Widespread sympatry, but no direct evidence of interbreeding, despite claims otherwise (e.g., Salomonsen 1928, 1951,Williamson 1961, Harris et al. 1965, Troy 1985). “Intermediate” phenotypes show part of normal range of plumage variation in C. f. flammea and C. h. exilipes (Molau 1985; Knox 1988; Herremans 1990; Steven Mlodinow Longmont CO -- You received this message because you are subscribed to the Google Groups "Colorado Birds" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
