The following is a wonderful commentary by fellow Jersey birder, John Workman, whose warmth, sense of wonder comes through in everything he writes. With John’s permission, the following is a post from the NJ Listserv about Pine Siskins:
“…day or two ago, Susie R. asked if siskins were “stocking up reserves” for
the trip back north. They do beef up whenever and wherever they can, even
though siskins might not all fly north for a while yet. These highly active
birds eat a lot because they have to in order to survive in the harsh, cold
In fact, research done in the ‘70s and 80s in Michigan on cardueline
finches showed that Pine Siskins have an amazing ability to withstand extreme cold.
If they are able to remain dry and out of the wind, they can endure
temperatures of 60 to 70 degrees below zero Centigrade (which, if my math is
correct, would equal 76 to 94 degrees below zero Fahrenheit).
This is because Pine Siskins have a metabolic rate that is about 40% higher
than expected for a bird of this small size. Hence their appetites and
their ability to endure nights colder than anything we’ve experienced in NJ
since, say, when the ice was a half-mile thick over Sussex County.
In Quebec, Pine Siskins have been reported feeding at 2:30AM under
floodlights. Survival isn’t easy for a boreal bird.”
Oops…running low on thistle. Gotta run to my local Weiss Ecology Center and pick up more….