Perhaps I should title this "the value of perches to birders," as Mike
Smith's story of his punctual merlin reminds me of the big western hemlock
tree in the ravine behind my house which I treasured. For the first winter
I lived there, the tree was a magnet for raptors. Almost every day there
was either a merlin, sharp-shin or red-tail perched on top of it, and I saw
3-species displacements a couple of times (one of the small species would
displace the other and in turn be displaced by a red-tail, in a short time
period). I watched a merlin eat a junco in it from beginning to end in my
spotting scope one day, saw each leg in turn pulled loose and disappear
down its throat. This tree was the highest tree for several blocks around
(I say "highest" because it stuck up the farthest into the sky; there were
taller trees below it in the ravine).

Anyway, a windstorm knocked it partway over, so it is leaning against a
maple and is now not the highest perch in the neighborhood, and the canopy
must look monotonous from the standpoint of a raptor. Hawks have very
rarely landed in it in the two subsequent winters, and I conclude they
really seek out the very highest perch in an area. It makes sense.
Interestingly, I don't think there has been any reduction in the number of
band-tailed pigeons or flickers that perch in the top from time to time.

Relative to punctuality, I have three partial albino chickadees in my yard,
and you can readily use birds such as these that are individually
recognizable to monitor occurrence. Many birds are quite regular in going
about their rounds.

Dennis Paulson