6.4 [SFBirds] Re: [SFBirds] Lincoln Park/
Fort Miley- RB Grosbeak
Dan and Joan Murphy wrote:
>
> I wonder if these Hutton's Vireos are residents or migrants?
Could this
> be their second nesting attempt?
>
As per Kaufmann in "Lives of North American
Birds", HUVI is mostly
non-migratory, but there is some evidence of downslope migration
in fall and
winter. HUVI is a common Brown-headed Cowbird host and has typically
one
and occasionally two broods a year.
Given the lateness of the date, one could
postulate that this is indeed a
second nesting attempt, due perhaps to a failure (or nest parasitism?)
of
the first brood.
Hugh,
Any evidence of nesting activity other than vocalizations?
6.4 [SFBirds] Another report on the BirdBox...
...of a possible Broad-billed Hummingbird
in the Arboretum.
6.9 [SFBirds] Small successes...
...I was wondering why the DOWNY WOODPECKER
had been spending so much time
around the house. Of course, they nested in the snag two houses
down this
spring.
Maybe I should go out into my backyard a little more often... :-|
6.11 [SFBirds] New yard bird
There's at least one CLIFF SWALLOW
flying up and down the boulevard in front
of my house. This is very good news because it probably means
that they're
breeding somewhere other than at Lake Merced. Maybe I'll scout
for the nest
today.
6.14 [SFBirds] AM birds...
...a WILLOW FLYCATCHER was (still?)
present at the East Wash this morning.
European Starling and American Robin have bred, in case there
was any
doubt. At Middle Lake, a Grosbeak sp. was singing. Also, there
were three
Red Foxes on the bar at the south end of the lake, which is rapidly
drying
up.
East Wash
American Goldfinch 5-8
Lesser Goldfinch 2-3
Willow Flycatcher
Western Wood-Pewee
Black Phoebe 2, including one apparent juvenile
Wilson's Warbler 2-3
Middle Lake
Grosbeak sp.
Wilson's Warbler 3
Grosbeak sp.
Red Fox 3, possibly two kits
6.14 [SFBirds] Re: [SFBirds] Question about
Common Yellowthroats
Erika Arul wrote:
>
> Does anyone know the status of Common Yellowthroats in San
Francisco? I'm
> relatively new to the area, and saw one (heard two) at the
Northeast bridge
> (wooden bridge) of Lake Merced. This is the first time I've
seen one in the
> city.
>
Common Yellowthroat has only been confirmed
breeding in one atlas block in
San Francisco, but probably breeding in three others. Breeding
records are
small due to difficulties in locating their nests, a dearth of
suitable
habitat and other environmental degradation. The wooden bridge
at Lake
Merced is one of the better locations in SF to find such a bird.
Conventional wisdom is that the species is declining in SF.
6.23 [SFBirds] Re: sf rare birds
Dan and Joan Murphy wrote:
>
> Attached is the list I made of "rare" birds of
SF. Since I won't be
> able to make the SFFO meeting on Friday I thought you might
like to see
> it. I think it would be appropriate for publication by SFFO.
One thing
> we should consider is how we update this document. Some
people want to
> add species that are new species to SF like Steller's Jay
and Hairy
> Woodpecker. I'd prefer seeing it represent those species
that are
> established and are losing their foothold in SF.
>
Here's a slightly different take on the same
subject, admittedly from the
standpoint of breeding birds only, taken from the atlas data.
I compared
relative abundances of breeding species (per block, obviously)
between San
Francisco and Marin and selected those breeding species which
have an
abundance of more than 50% in Marin relative to SF. While this
is crude at
best (e.g. there has been no attempt to correct for the Farallones
or the
relative distribution of suitable habitat (left) in the two counties
and
there are no corrections for irruptive species and statistical
fluctuations
in San Francisco are large due to the small number of blocks),
I think it's
a pretty good start at figuring out those breeding birds that
are in trouble
in San Francisco.
Bewick's Wren
Wrentit
Cliff Swallow
California Quail
Spotted Towhee
Steller's Jay
Red-tailed Hawk
Pacific-slope Flycatcher
Great Horned Owl
Violet-green Swallow
Hutton's Vireo
Orange-crowned Warbler
Western Meadowlark
Horned Lark
Note that the list is sorted from less common
in SF to more common. There
are others (e.g. Swainson's Thrush, Bullock's Oriole, etc.),
but without
doing a better job of systematics, I don't think the data is
as meaningful.
Curiously, using the same metric, both Pigeon
Guillemot and White-crowned
Sparrow are significantly _more_ common as breeding species in
San Francisco
than in Marin. While the former may be an aberration due to the
relative
number of census blocks with shoreline habitat between the two
counties, it
seems clear that White-crowned Sparrow is not threatened in San
Francisco as
a breeding species.
6.24 [SFBirds] Quail...
There were 4-5 CALIFORNIA QUAIL in
the Arboretum this afternoon, including
one female.
6.25 [SFBirds] Re: [SFBirds] Quail...
Alan Hopkins wrote:
>
> Hi Mark,
> Thanks for the report. I had a group of quail watchers in
the Arboretum
> Sunday between 10 and 12. We saw three or four males, but
no female, no
> one has seen a female for days, was she in the California
garden?
>
The female was sighted at the extreme northwestern
corner of the California
section, right by where that little section of the California
natives curls
behind the pond enclosed by a cyclone fence. There's a small
bed which
doesn't have California natives in it (I don't think) and just
north of
there is a Silver Tree (which is a species of tree from Cape
Province).
6.26 [SFBirds] Re: [SFBirds] Mt. Davidson,
06/26/01 (7:05-8:25 AM)
Paul Saraceni wrote:
>
> RED-BR. NUTHATCH 1 f. or juv.
Listed as "fairly common resident locally"
along the coast, presumably in
counties that actually have endemic habitat suitable for the
species, unlike
San Francisco. The city distribution lists it as "rare"
in summer, which is
probably about right.
6.28 [pen-bird] Re: [pen-bird] Common Yellowthroat
At 08:05 PM 6/27/2001 -0700, Mark
W. Eaton wrote:
>Which subspecie(s) of Common Yellowthroat are found in San
Mateo county?
The breeding birds we have here are Salt Marsh
Common Yellowthroats, also
known as San Francisco Bay Yellowthroats. More properly they
are the
subspecies _sinuosa_. In winter we receive, larger, paler, brighter
yellow,
longer-winged birds from further north. These probably are mainly
the form
arizela, but others may be involved. This is part of an ongoing
research
program of the San Francisco Bay Bird Observatory where we are
measuring
live birds, residents and migrants as well as museum specimens
to determine
the exact distribution and identification criteria for the Salt
Marsh
Common Yellowthroat. By using multivariate statistical techniques
we are
able to obtain a clearer picture of size variation in the different
forms
than has been published previously. Its important to determine
the real
distribution of the Salt Marsh Common Yellowthroat as it is considered
a
California species of special concern. Without accurate data
its impossible
to know if this form is increasing, decreasing, stable or even
if it
deserves to be listed under that category.
regards
Al [Jaramillo]
6.30 [SFBirds] Re: [SFBirds] 6/30/01 - Northen Parula
Htcotter@aol.com wrote:
>
> Hi All
> Eric Preston and I birded around the city for a couple of
hours this morning. Highlight was a singing male Northen Parula
at the entry road to the Harding Park Golf Course and the Boathouse
off Skyline.
Rich and I had the bird between 5:00 and 6:00 this evening. I did manage to grip and rip three shots when the bird came down to the albezzia on the south side of the entrance road; perhaps one will be almost in focus :-)
You can contact me via email.