Naturespeak A naturalist's view of the world

December 12, 2007

Finchfest 2007

Filed under: Uncategorized — wykes @ 10:22 pm

  The winter finches are here and they are hungry.  The northern U.S. states are currently experiencing a mass visitation of tiny seed eating birds looking to satisfy their collective need for feed.  Thousands of Common Redpolls and Pine Siskins have moved south from their Canadian homeland to invade our border states.  Unlike their human counterparts who are here to spend their precious Loonies, these feathered Canadians are here for our Alders. 

  You could say they are refugees of a sort. The food resources in their native haunts have run short and they have made the southern run out of necessity. This “migration of necessity,” which occurs only on an irregular basis, is properly termed an “irruption.”  As a whole these little invaders are therefore called “irruptive winter finches.”  Repeat after me: volcanoes erupt, finches irrupt, and small impatient children interrupt.

  Although there are other irruptive birds, such as the snowy owls (one of which is currently hanging around the Lost Peninsula by Toledo, Ohio), the Redpoll and Siskin are the most common of the winter visitors.  Pine Siskins (see here) are easily identified by their heavily streaked brown and cream decor. The Common Redpolls sport little black trumpet player’s beards and rosy forehead patches (see here).

  Both birds are about the same size – which equates to around 10 grams. It might help you to picture a stack of four pennies as a way to judge what 10 grams feels like. Unfortunately, this demonstration depends upon which year those pennies represent – the post 1982 pennies weight 2.5 grams while the earlier ones weight 3.1 grams. Canadian pennies, which would be more appropriate in this case, run the gamut from 3.24 grams to the present 2.35 grams. In this scenario we could say they weight as much as four post 1982 U.S. coppers or about three 1978 Canadian pennies or….let’s just forget it.  Suffice it to say these birds are lightweight little balls of down that need lots of food to get them through a tough winter.

  One study estimated that a redpoll can eat up to 40% of its body weight (in Canadian coinage, of course) daily. While the Siskin just gobbles its food straight, the Redpoll has the ability to temporarily store seeds in a throat pouch called a divercula.  It then can leisurely swallow the seeds at a later time and in a predator free place. Clever little Canadians, eh?

  The abundant crop offered by a tree known as the Alder is the freezer meal of choice around these parts. European Alders, or Black Alders, are introduced members of the birch family which bear pine-like cones (strobiles). They prefer wet areas and are often found bordering marshes or rivers. The tree is deciduous and dutifully drops its leaves each fall, but they retain a heavy crop of ¾ inch cones which gives them the winter appearance of full foliage.

  The finches go bonkers on these alder cones and pry out the tiny seeds from between the scales.  Many of the seeds fall to the ground and the birds spend a good part of their day picking them off the snow as well.  As long as the alder crop holds out, they will stick around.

  If you don’t have an Alder tree, there’s still a pretty good chance that you’ll spot these fascinating frigid finches if you maintain a bird feeder. They love to eat out.

1 Comment »

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    Comment by bird feeders squirrel proof — August 17, 2009 @ 3:29 pm

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