Re: [SBB] American Dipper in Stevens Creek

["Garth Harwood" <[[email protected]]>]

One more data point to add to this thread: in early December 2004 I did
encounter an American Dipper in the upper Stevens Creek drainage -
supporting Les's "backwards" information on their seasonal movement
patterns. I think it makes sense for them to move upstream in our area due
to the augmentation of stream flows by winter rains.

At my home on Pescadero Creek (SM County) I see Dippers mostly in the late
summer/early fall. My place is low in the watershed with calm waters that
ordinarily wouldn't be of much interest to a Dipper - but as David notes,
there probably isn't much choice in our region at the low-flow season.

--Garth Harwood


----- Original Message ----- 
From: "Les Chibana" <[[email protected]]>
To: "South Bay Birders" <[[email protected]]>; "David Suddjian"
<[[email protected]]>
Sent: Wednesday, March 09, 2005 12:05 AM
Subject: Re: [SBB] American Dipper in Stevens Creek


> David's comment nudged me to pull out a copy of the Birds of North
> America account for the dipper, and it's good that I did. I had it
> backwards, in the dipper's range, where it freezes in winter, they move
> downstream. Of course, that shouldn't apply here.
>
> The author, Hugh E. Kingery, says that there are 3 types of migratory
> behavior: nonmigratory, in-stream, and interdrainage. So, they either
> stay put, move within the same stream, or move between streams. I
> recall that in one major study in the Colorado Front Range they
> detected a dipper flying outside of its drainage only once. Kingery
> notes that there are only a few documented interdrainage flight
> movements and suggests that these generally occur at night. It seems
> that this is one of those species that are difficult to track for
> migrational data. It does not appear that there is much data if any
> from banding efforts to indicate movements outside of home drainages.
>
> Among the dipper locations within the county, Stevens Creek seems to
> maintain a reasonable flow year-round, undoubtedly being augmented by
> outflow from springs. Doesn't Twin Creeks, upstream from Almaden Res.,
> flow year-round? And Penitencia Creek in Alum Rock Park is perhaps a
> bit more intermittent.
>
> I don't doubt that David has a good grasp of presence of most species
> in the areas he frequents. And as he asks, where do they go?
> Apparently, someplace that we don't check...
>
> Les
> ---
> Les Chibana
> BirdNUTZ(tm) - Ornigasmic Birding
> Palo Alto Baylands Birding Classes
> em <[[email protected]]>
> web <http://www.birdnutz.com>
> ph 650-949-4335
> fx 650-949-4137
> snailmail: SR2 Box 335, La Honda CA 94020
>
>
> On Mar 8, 2005, at 8:48 PM, [[email protected]] wrote:
>
> > In a message dated 3/3/05 4:14:04 PM Pacific Standard Time,
> > [[email protected]] writes:
> >
> >
> > They may be
> >  difficult to locate in winter because they are believed to move higher
> >  into their drainage in winter. Or, maybe they aren't looked for much
> > in
> >  winter and are under-reported.
> >
> >
> >
> >  FWIW, I believe that a significant portion of the dippers that nest
> > or are reared in the Santa Cruz Mountains go elsewhere by late summer.
> > Some are apparently year-round residents, but my take on the
> > population as a whole is that many depart from some streams entirely
> > or from large parts of streams when stream flow conditions deteriorate
> > by sometime in the summer. There are very few of our local streams
> > that provide suitable dipper habitat in late summer and early fall.
> > Without trying to lay out the case for this opinion, I'll just say it
> > is based on observations on a number of the local dipper streams at
> > various seasons, and especially during a transition period that spans
> > the nesting season into summer. But if I'm right that some depart, I
> > wonder where they go?
> >
> >  David Suddjian
> >  Capitola, CA
> >  [[email protected]]
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