Actually, the PNW coast Black-capped Chickadee is a quite distinct subspecies, even recognizable in the field as different, so it has surely been in this region for a while (but who knows how long it would have taken to evolve that difference?). As Gene said, it isn't really adapted to the climax vegetation here, which is the Chestnut-back's domain. Black-caps were probably originally in the alders, maples and cottonwoods along the rivers. Black-capped have been local on the Olympic Peninsula and have doubtless increased with the cutting of the original forests and regrowth of broadleaf species. Their absence from Vancouver Island is telling, as they are common all around it on the mainland. Chickadees are not known as good over-water dispersers, yet Chestnut-backed has done well at that in this region.

Black-caps like deciduous, Chestnut-backs coniferous forests, to say it most simply. Where the two forest types are mixed it's not at all unusual to find both species. It's the same for Black-caps and Mountains east of the Cascades, and both of those species come to feeders together in many areas, I have heard. Mountains are in drier, more open conifer forests than Chestnut-backs, but those two species occur together up in our eastern mountains. Perhaps someone in the region has three chickadee species coming to their feeders. Anyone?

Many of you know that the Puget Sound Black-capped have their own distinct song dialect, quite different from the rest of their species. That has been studied, but not recently, and it would be interesting to have a survey done of the entire region from Vancouver, BC, to Portland or beyond, so learn what the prevailing chickadee song is in each area. A two-noted whistle (feeeee-beee) describes it all across the continent, including in eastern WA, but here in the PS region the whistles are multiplied, often around five at a time (feee-bee-bee-bee-bee). What do your chickadees sound like? They are starting to whistle now, at least in my yard.

Dennis

On Mar 27, 2012, at 8:11 AM, Lee Rentz wrote:

> That the Black-capped Chickadee might be a recent arrival in the Pacific NW is an interesting hypothesis. As I recall, the coloration of the bird here is "dingier" and darker than its midwestern relations, as are several other species of birds, perhaps for the camouflage advantage under our dark and rainy skies. If this is the case, it is possible that evolution by natural selection would have happened fairly quickly (if we are talking about a relatively short time frame). I have always wondered why the Chestnuts and Black-caps come to my feeders together, and seem to occupy such a similar ecological niche.
>
> Lee Rentz
> lee at leerentz.com
>
> >Tweeters,
>
> I've thought that the scarcity of Black-capped Chickadees on local islands
> may be evidence that the Black-capped is a relatively recent arrival in the
> PNW from the eastern forest, perhaps an early harbinger of the Barred Owl.
> Chestnut-backed Chickadees appear more obviously morphologically adapted to
> the PNW habitat. Note also that the Black-capped ranges no further south
> than northwesternmost California while the Chestnut-backed ranges further
> south.
>
> Gene Hunn
> Petaluma, CA
>
> -----Original Message-----
> From: tweeters-bounces at mailman1.u.washington.edu
> [mailto:tweeters-bounces at mailman1.u.washington.edu] On Behalf Of Charlie
> Wright
> Sent: Monday, March 26, 2012 10:22 PM
> To: tweeters at u.washington.edu
> Subject: [Tweeters] Re: status of Black-capped Chickadee in the San Juan
> Islands
>
> Hi Charles,
> Thanks for starting this discussion about chickadees, the San Juans, and
> eBird.<
>
> _______________________________________________
> Tweeters mailing list
> Tweeters at u.washington.edu
> http://mailman1.u.washington.edu/mailman/listinfo/tweeters

-----
Dennis Paulson
1724 NE 98 St.
Seattle, WA 98115
206-528-1382
dennispaulson at comcast.net



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