Re: [SBB] Canada Goose - What's wrong with this picture? [Some clean up]

[Bill Bousman <[[email protected]]>]

Folks:

I think Alvaro has pretty much answered the original question.  Let me just 
add some boring details and correct a few bits of misinformation.

1. Lisa's information is a bit out of date.  The Birds of North America 
account (also out of date) describes the 11 subspecies that Lisa 
noted.  Subsequently, the species was split in two: Canada Goose and 
Cackling Goose.  The Canada Goose now includes 7 subspecies that the BoNA 
described as the large forms:
         B. canadensis canadensis
         B. c. interior
         B. c. maxima
         B. c. moffitti
         B. c. parvipes
         B. c. occidentalis
         B. c. fulva
Cackling Geese are equivalent of the four small-forms in the BoNA account 
and include four subspecies:
         B. hutchinsi hutchinsi
         B. h. taverneri
         B. h. minima
         B. h. leucopareia
Now, for real goose aficianados, there are still some fine hairs to split 
when talking about B. c. parvipes, which is a small Canada and B. h. 
taverni, which is a large Cackling Goose.  Life in central California is 
much easier if we ignore the occasional funny inbetween geese and 
concentrate on: (a) wintering Canadas, which are moffitti (more below), (b) 
wintering Cackling Geese, which are usually either "Aleutians" 
(leucopareia) or "Cackling" (minima), and (d) the resident geese Alvaro 
described, which may be a mixture or may be mostly moffitti (more below).

2. There was a time, not so many years ago, when the only geese we had were 
true wintering Canadas.  These were moffitti, probably birds that nested in 
northeastern California and northern Nevada (as they have always done and 
still do).  But, it you wanted to see them, you went to Crystal Springs or 
Calaveras reservoirs.  They almost never occurred in the northern Santa 
Clara Valley.  In those days, if a Palo Alto CBC party reported a Canada 
flock overhead there were cries of "Good bird, good bird."  These wintering 
Canadas are still found in these two spots, but who knows if they ever join 
their friends in the valley now.

3. Alvaro described one of the histories of our local feral geese, but that 
is just one history.  Dave Shuford has described a different history in the 
Marin Breeding Bird Atlas that I prefer, and that is that our first birds 
were moffitti imported from Nevada.  Although there are a number of earlier 
breeding "events", the mainstream breeding seems to have started in Oakland 
in the late 1950s and spread south along the East Bay with first breeding 
in Santa Clara County in 1986.

4. If you look at our wintering Cackling Geese, you will notice a short, 
stubby bill, a flattened head, and a proportionally shorter neck.  If you 
look at Vivek's nice photos what you see is a smaller bird, but with 
identical proportions.  Alvaro has been nice enough to point out that this 
is not untypical for a smaller female.

Bill



At 02:39 PM 5/11/06, Alvaro Jaramillo wrote:
>Another point:
>
>    These Canada Geese we have breeding in the Bay Area are of mixed stock, a
>creation originally to try and re-stock the Giant Canada Goose (maxima) in
>the Midwest. Folks then just kept on introducing these mixed stocks
>throughout the continent, why, I don't know, but they did. This is where the
>largely non-migratory park stock that we see here may have come from. As
>such, it is difficult to pin them down to any subspecies but I suspect that
>they are mixes of moffitti/canadensis/maxima or something like that. Big
>pale races overall. But a general thought about subspecies. They are partly
>defined on morphology and partly on breeding distribution. Birds of two
>subspecies don't tend to be found in the same area. So if this was a cleaner
>(wild) population of Canada Geese we were talking about here, we would not
>expect to ever see two subspecies interbreeding, this is because by
>definition they would be the same given that they are breeding in the same
>area. Therefore we would attribute visual differences to variation within
>the subspecies. Note that when we do have some northern geese oversummering
>here (White-fronted in Foster City for example) they do not breed, the same
>would be expected of any sick or injured migratory Canada Goose that
>remained down here for a summer.
>
>Regards
>
>Al
>
>Alvaro Jaramillo
>[[email protected]]
>Half Moon Bay, CA
>
>Field Guides - Birding Tours Worldwide
>http://www.fieldguides.com/home.htm
>
>
> > -----Original Message-----
> > From: [[email protected]] [mailto:south-bay-birds-
> > [[email protected]]] On Behalf Of Lisa Myers
> > Sent: Thursday, May 11, 2006 2:01 PM
> > To: Tiwari, Vivek; SBB
> > Subject: Re: [SBB] Canada Goose - What's wrong with this picture?
> >
> > Hello Vivek -
> >
> > I remember when my goal was simply to remember to call
> > this goose a Canada Goose and not a Canadian Goose,
> > let alone try a learn all the subspecies.
> >
> > Last year in Les Chibana's Palo Alto class he spent
> > two nights of lectures going over all the sub-species
> > of the Canada Goose.
> > Below is a list of what I quickly found on the
> > internet.
> >
> > Subspecies: Branta canadensis canadensis
> > Subspecies: Branta canadensis fulva
> > Subspecies: Branta canadensis hutchinsi
> > Subspecies: Branta canadensis interior
> > Subspecies: Branta canadensis leucopareia
> > Subspecies: Branta canadensis maxima
> > Subspecies: Branta canadensis minima
> > Subspecies: Branta canadensis moffitti
> > Subspecies: Branta canadensis occidentalis
> > Subspecies: Branta canadensis parvipes
> > Subspecies: Branta canadensis taverneri
> >
> > So I suspect your pair is a combination of two
> > different subspecies.
> > I also suspect more information is coming our way.
> >
> > Lisa Myers
> >
> > --- "Tiwari, Vivek" <[[email protected]]> wrote:
> >
> > > Took the following photograph in Alviso on May 1st.
> > >
> > > http://www.flickr.com/photos/30419272@N00/144705030/
> > >
> > > Two (presumably) adult Canada Geese with chicks. 1
> > > chick visible at
> > > bottom of the picture
> > >
> > > If so, why the big difference in size in the two
> > > "adult" birds?
> > > Is this a pair? Is there sexual dimorphism in this
> > > species? Are these
> > > different subspecies?
> > >
> > > If not a pair, is the smaller, slender bird an
> > > immature from an ealier
> > > year/brood?
> > >
> > > Or just a perfectly normal variation, nothing
> > > strange here?
> > >
> > > Don't know if its relevant but the smaller / slender
> > > bird appeared to a
> > > bare patch of the forehead as seen here:
> > > http://www.flickr.com/photos/30419272@N00/144711875/
> > > A sick bird?
> > >
> > > Thanks!
> > >
> > > Vivek Tiwari
> > >
> > >
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