Friday, February 10, 2017

Black-capped Chickadee

A Black-capped Chickadee from the University of Minnesota Landscape Arboretum. The sharply defined black bib suggests a Carolina Chickadee, but the pale wing coverts are typical of Black-caps. The two species do hybridize where their ranges overlap. Minnesota, however, is well north of the Carolina’s range. The hybrid zone is moving north—about 20 km from 1986 to 2003 and 100 kim from the 1930s to 1980s. Carolina Chickadees replace Black-caps as the hybrid zone moves north  (Foote et al. 2010).

 During our cold nights, Black-capped Chickadees lower their body temperatures, even entering “controlled” hyperthermia (Foote et al. 2010). These chickadees also break down organ proteins to generate heat. Our cold nights appear to be becoming warmer over time. Today we are heading for a possible 50 degrees F in Minneapolis. The all-time record low for the state on this day was -49 in northern Minnesota.

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