I enjoy watching the birds in my back yard but the sparrows have
monopolized the feeders.I get some chickadees,titmouse,cardinals,
and a Downy woodpecker.
   I opened a birdhouse and found 4 dead chickadee babies.Those 
damm sparrows.
 
  I started wondering if ,in these days of electronics,if it was
possible to make a bird box that would be selective .If a box
would only allow birds in with the color blue,bluebirds only could 
come in if the entrance hole was small.Bluejays would be too large.
  Similiarly,a barrier that would prevent brown birds from entering
would keep out sparrows,and allow chickadees in.
  
  A box could be powered with a small battery and photovoltaic cells 
on the side of the box.A color detector at the entrance would 
make choices.I'm assuming daytime conditions.
The only problem is HOW to activate a barrier for going IN and 
for going OUT.Maybe some kind of fiberoptic sensor.
And HOW to design a mechanical barrier that stops a bird.
 
  I'm sure a computer program could be written for different 
situations.  I'll have to think more about this some more.
 
 
 
 
 

--- Maximus 2.02