David Wright wrote:

>And the other 3 are tree-nesters, right? I wonder how many ground-
>nesters fledge young in suburban Seattle. Not to revive the dreaded
>"C" thread, but it sure would be nice to have Wilson's Warblers nest
>in the backyard. The last two springs we've had a singing male Wilson's
>linger for over two weeks in the backyard (but apparently female Wilson's
>are too sensible to consider nesting here).

Every spring and sometimes into the summer I have singing Wilson's Warblers
and Black-headed Grosbeaks, Olive-sided Flycatchers and Western Wood-Pewees
in the ravine behind my house, but I've never been convinced they bred in
the neighborhood. I don't think it's only ground nesters in which the
females reject our backyards as habitat. Females may well be better
habitat discriminators than males, as they are programmed to seek optimal
nesting habitat as well as optimal foraging habitat. I think that migrants
in general don't like urban habitat patches, and part of it may just be
their patchiness. If only a couple of birds settle into a small urban
patch, they may both be the same sex. If you're seeking a mate, better to
go to large continuous stands, where almost surely there will be members of
the opposite sex. This isn't a problem for resident species, which have
all year to sort out their home ranges.

>If Audubon is serious about campaigning to enhance suburban habitat
>for birds (fide recent statements from NAS), it will be necessary to
>risk unpopularity by educating people on this topic and advocating
>enforced leash-laws for cats. Planting lots of natives in our yards
>will make little difference for ground- and near-ground-nesting birds
>(which seem especially vulnerable to cat predation) until we deal with
>the C-problem.

Unfortunately, there seems to me to be two similar C-problems: the cats on
the ground and the crows in the trees. Add to that the third C-problem,
the cowbird females that are such good nest finders. I can envision an
Audubon poster to that effect: "The Three Cs that Spell Catastrophe." I'm
serious. We can tell cat owners to curb their cats until the cows come
home, but how about those two native birds that are such serious factors in
the equation?

Dennis Paulson, Director phone 206-756-3798
Slater Museum of Natural History fax 206-756-3352
University of Puget Sound e-mail dpaulson at ups.edu
Tacoma, WA 98416