On Sun, 10 Jan 1999 bboek at olympus.net wrote:

> Tweeters (and Michael)
>
> Last week (early January) I mentioned the following about Song Sparrows
> in Sequim:
> >> I can add that the Song Sparrows have been
> >>singing with surprising vigor in the morning during the last week in
> >>Sequim.
>
> To which Michael commented:
> >Considering that many of the birds we're hearing in the region at this time
> >of year are very likely northern migrants supplanting spring and summer
> >residents which winter further south, I suspect these birds' songs and
> >behavior have little to do with breeding--which would require them to be on
> >or heading to breeding territory, which won't happen for at least another
> >three or four months--and much to do with establishing and maintaining
> >positions of status within the winter-flock hierarchy in the case of the
> >blackbirds and proclaiming winter feeding territory in the sparrow's
> >instance. Why evolve a new set of songs and behavior for use on the
> >wintering grounds when the set they use for breeding work just as well for
> >the different purposes?
>
> Out of curiousity, I checked with Gene Kridler, who has banded birds for
> several years on the north Olympic Peninsula. He said he has recaptured
> the same individual Song Sparrows throughout the year at their apparent
> breeding sites, suggesting that at least some Song Sparrows are resident
> here. And despite banding many Song Sparrows, he has not had any
> recoveries outside the area. He has had recoveries elsewhere of other,
> obviously migratory species, such as Zonotrichia.
>
> There certainly are migrant Song Sparrows that increase "winter"
> populations here, but are you sure that Song Sparrows at this latitude
> are all migrants? I assumed, perhaps incorrectly, that many Song
> Sparrows here remain on territory throughout the year, such as occurs
> farther south in Oregon and California. There, studies of Song Sparrows
> banded as chicks have shown that some travel no more than 1/4 mile from
> their natal nest their entire lives. Do you have, or know of, any
> information on the proportion of resident to migrant Song Sparrows in
> coastal B.C. and Washington in winter?
>
> Are there any other local banders (like Jon Anderson?) or anyone else who
> can answer this question -- are Song Sparrows in lowland western
> Washington typically resident all year, or do most if not all migrate and
> are consequently replaced by other migrant populations in winter? If
> some Song Sparrows are resident, then it seems that winter singing may
> help establish breeding territories, if prime breeding locations are at a
> premium. If all migrate, then winter singing would help establish
> feeding territories unrelated to breeding, as Michael says.
>
> Bob Boekelheide
> Sequim
>

OK, since I've spent a good portion of my waking hours the last 4 years
banding and observing song sparrows at Discovery Park in Seattle, I'll
take a quick shot at it.

Short answer: Cascadian song sparrows are not migratory.

Longer answer:

The song sparrows in Discovery Park are for the most part year-round
residents. I and my colleagues have color-banded every territorial male
(and some females) in much of the park going back to 1988, and they're
present on their usual breeding territories through the winter, although
they're much harder to find in the winter since they're more retiring.
>From Jamie Smith's and Peter Arcese's work on Mandarte Island, near
Sydney, BC, and on the BC mainland near Vancouver, I understand the
situation is very similar there.

Do *none* of the local sparrows migrate? We can't say that - in fact, we
are highly suspicious of a couple individuals who are very hard to find in
the winter, and who seem to appear suddenly in March. These birds
may just be wintering at a bird feeder just outside our normal area of
coverage, or they may be migrating further than that. That's literally a
couple individuals out of a hundred fifty or so, though. Ninety percent
or more are here year round.

Do wintering sparrows from farther north supplement the local residents
during the non-breeding season? Bob says "certainly," which may be a bit
strong. There are probably *some*, but I don't know of any banding data
that confirms that beyond a doubt, and even if there are some, they may be
so scarce as "slate-colored" juncos or "yellow-shafted" flickers. If you
see more sparrows in winter than in breeding season, remember that even
without migration, the local population is swelled by the young of the
year in the fall and winter, and and these young disperse into new areas,
and may concentrate more than the adults. In Discovery Park, we do
sometimes band "new" adult birds in winter that disappear by breeding
season. These may be wintering migrants. On the other hand, they may be
local birds that died before breeding or couldn't successfully defend a
territory in our area and moved a half mile away. Occasionally I see song
sparrows in winter that subjectively look paler than the locals, and I
suspect those are wintering migrants. But in Discovery Park, at least,
wintering migrants from further north couldn't make up much more than a
tiny fraction of the wintering birds.

I suspect that *if* wintering birds from farther north are a regular and
significant part of our wintering song sparrow population, it's very
habitat or locality dependent. Along the coast, or at places like the
Skagit flats, where migrants of all sorts concentrate, might be the best
place to find winterers from farther north.

But that's speculation. What I/we *know* is that at Discovery Park and
Mandarte Island, summer or winter, more than 9 out of 10 song sparrows,
and quite likely more than 99 out of 100, are local, non-migrating birds.

And as soon as the days start lengthening, every year, they start to crank
out songs.

Christopher E. Hill
Department of Zoology
University of Washington
P. O. Box 351800
Seattle, WA 98195-1800