[CT Birds] What Birders do on a snowy morning...plus Blue Jay observation

Barbara Garrett barbaragarrett at optonline.net
Thu Dec 27 13:53:08 EST 2012

Did you take into account that a Dove has a crop and therefore is gathering, but not necessarily feeding?

Separately, I've noticed a total absence of Blue Jays this winter.  All the other usual suspects are here and we had a robust Jay population this summer.  Maybe they've gotten picked off by the hawks???

north Stamford
  ----- Original Message ----- 
  From: Carrier Graphics 
  To: ctbirds at lists.ctbirding.org 
  Sent: Thursday, December 27, 2012 10:46 AM
  Subject: [CT Birds] What Birders do on a snowy morning...

  What Birders do on a snowy morning...

  I look out at the 6 new inches of snow, and find the birds
  are all over the feeders. On my window screen feeder are 3 Mourning Dove, and 
  4 Junco. I notice how the Doves seem to be eating many more seeds per second
  that the juncos. I know this happens because all those in the Dove and Pigeon 
  do not need to crack open seeds, just eat them whole, and let their crop do the 

  So: I count how many seeds are picked up per minute for each species, then 
  average out the short periods of time they are not picking up seeds per min. Ex- 
  walking over to a new seed area, head lifting for danger, etc. And here is what 
  I came up with...


  On average, a Dove picked up 5 seeds per second X 60 = 300 seeds per minute.
  minus 6 intervals of 2 sec each = 12 seconds, 12 X 5= 60 seeds
  So 300 seeds per minute, minus 60 seeds less for intervals = 

  The MOURNING DOVE eats 240 seeds per minute!


  On average, a Junco picks up 1 seed and cracks it open and swallows 
  it at one per second X60 = 60 seeds per minute.
  The Junco takes 10 intervals of 2 seconds each = 2 X 10 = 20 seconds = 20 seeds.
  So 60 seeds per minute, minus 20 seeds less for intervals =

  The JUNCO eats 40 seeds per minute.

  The efficient DOVE eats 200 more seeds per minute. And this gives this much 
  larger bird a less chance of being taken by a predator from less time spent in 
  the open finding food than a JUNCO, because they do not need to crack open each 
  seed at the site of the food, but can digest them from the safety of a tree or 
  such that affords them safety from a predator. Yes?

  Paul Carrier - Harwinton
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