As always, a good post by Jim McCormac, this time on the kestrel and  merlin.

I forgot to mention "pigeon hawk" as another of the raptor misnomers (now
corrected).

But Jim's account of the recent declines in American Kestrel numbers, both
here in Ohio and in the larger region, is worth considering. In the 60s and
70s,  kestrels were about as common as Red-tailed Hawks and were commonly seen
flipping their tails on rural utility lines all over the state. Today, such
sightings are much less common. Why?

Jim suggests that the lack of breeding sites may be a factor, and I'm sure
proper cavity nests are surely in decline. I've studied common Ohio raptors for
 over 30 years, and have noted that kestrels often nested in old farm
buildings,  often between old stacked hay bales or other interior small, protected
cavities.  But look at farm buildings today. Most of these old barns are either
altogether  removed, or have been completely tightened up with modern metal
siding. At the  best, kestrels today have a tougher time finding cavity nests on
human  buildings in rural areas.

There is, however, no real reduction in kestrel habitat. Kestrel habitat is
most commonly (and very successfully) the long but narrow strips of roadside
grassland the straddle all Ohio highways, large or small. Kestrels sit up on
the  utility wires or poles and take ubiquitously-resident voles  in the grass
strips below. We don't have any reduction in rural roads or ditches with vole
 populations.

The real problem, however, is an increase, not a decrease. It's the orders
of magnitude increase in Cooper's Hawks in recent years. Raptor watchers have
observed  Cooper's Hawks taking  the little falcons. Cooper's  hawks are
particularly adept at grabbing kestrel eyasses just when they try to  make their
first flights in June. A fully-fledged and flight-capable  kestrel adult can
just barely elude a Cooper's Hawk on a typical marauding  hunting flight of
opportunity. For two or three weeks in June, a young  kestrel just out of the nest
has no chance of evading the Cooper's talons. The  inexperienced young little
falcons just sit up there on a wire and one after  another are plucked off by
the local Cooper's Hawk pair. Because kestrel prefer  to sit out on open
perches at the top of a single tree or utility pole, even if  the young kestrel
sees the approaching accipiter, it has no convenient place to  escape to.

Consequently, I strongly suggest that the marked decline in kestrel numbers
is a direct result of the population density expansion of the Cooper's Hawk,
which is a story of its own. Formerly, the bird was uncommon and very wary and
 skittish of humans. Check all the old writings on the bird, and they all
remark  about the hawk's reluctance to approach humans. Classic Cooper's stayed
out in  the woods and seldom ventured into cities or farmsteads for any times.
None ever  nested there.

Today, natural selection has eliminated these former Cooper's Hawk traits.
Today's population is overwhelmed with individuals that freely nest in urban
backyards (usually in evergreens). Urban (and rural) Cooper's are everywhere.
Why? Because they are now breeding so successfully, and that's because they
are  breeding in new prey-dense environments -- cities. Cooper's Hawks have
discovered that the modern, urban world artificially concentrates their prey,
small birds, in small, easy-to-attack areas -- backyard bird feeders.

Consequently, it is very reasonable to attribute the loss of  kestrel numbers
on backyard bird feeders. Birders like to conveniently blame the  "bad guys,"
those who spew pollutants and destroy habitats. But frankly, none of  that
fits with the biology of the modern kestrel. Predation by expanded  numbers of
Cooper's Hawk does. The real, basal causative factor is the  proliferation of
bird feeders -- a separate controversial topic altogether  (which I'll leave to
others, for sure).

--John A. Blakeman

______________________________________________________________________

Ohio-birds mailing list, a service of the Ohio Ornithological Society.
Our thanks to Miami University for hosting this mailing list.

You can join or leave the list, or change your options, at:
http://listserv.muohio.edu/scripts/wa.exe?LIST=OHIO-BIRDS
Send questions or comments about the list to: [log in to unmask]