Cool FactCommon Redpolls can survive temperatures of 65 degrees Fahrenheit. A study in Alaska found Redpolls put on about 31 percent more plumage by weight in November than they did in July.All About Birds - Common Redpoll
A natural history of the birds of New South Wales collected, engraved, and faithfully painted after nature /.London :Printed for J.H. Bohte,1822..biodiversitylibrary.org/page/57359594