10/31/11
Sometimes, you seek a river. It is a guiding
shaft of light that brings a shadow's swirling to
your weir eyes and you sense a peerless flow as
it seeps through a gaiting turn. There are birds
everywhere. There are species everywhere and you
know that, if you can absorb the offering, you
can take the moment, whether lifting a chaliced
record to your lips or bringing the lacing memory
of a close encounter or a new bird. The record
is yours. The memories are yours but the word
for bird is water and the rivers are nearly dry
and the weir is empty. You see a bird flash by,
not esthetically pleasing but you know what he
is. You hear another bird, who also yields to
identification. You continue walking but the
good looks are brief and few and the words mingle
in the distance, faint though distinct. The day
seems ambiguous but the birds, though sparsely
set, seem determined to evoke a new species with
every gleaning frame so that, one by one, we
bring into this knotting throe, yet another name.
The name for our walk is twenty-six and we have,
somehow, arrived well beyond the resolution of
any previous walk for week 44. The shades of
former walks speak in hushing tones and, although
I am sure that somewhere in their fog-lit
bottoms, there is the conjuring of a great image
or a wonderful conversation, none of them can
count above 23.
See the plots at
http://birdwalks.caltech.edu/bird_data/species_time.html
and
http://birdwalks.caltech.edu/bird_data/two_plots.htm
Sometimes, the key is innocuous, the beginning
inauspicious. I had to wait out plumbers at my
home in the morning and I made the starting point
for the walk rather breathless and with just a
minute to spare. We were leaderless as Alan was
out of town and the air seemed thick. Although
the temperature was only 70°F, it seemed quite a
bit warmer. We see no rock doves on top of
Millikan, certainly no disaster and not that
common but, when we do see them, it always puts
me in a hopeful mood regardless of the
conditions. So, we begin the walk with one caw
spread among four walkers and I'm thinking that
we may be in for a tough walk. As we pass along
the tennis courts, however, we get a
yellow-rumped warbler and Carole notices a pair
of mourning doves on a lawn through an open slat
in the adjacent wooden fence. It's hard to
explain why I found this "common" species to be
so invigorating, any more than I can explain why
the Millikan pigeons would have had the same
effect, but Carole's mourning doves left me
feeling that the walk might not be so bad after
all.
The Maintenance yard was not prolific in an avian
sense but we continued to collect walkers.
Things started looking up when we saw a western
meadowlark at the eastern end of the playing
field. This gives us three sightings for the
year, which puts us into fairly rarefied
territory (only 2009 with four and 1999 with five
can boast more meadowlarks). Tournament Park
yielded another hermit thrush. There was no
ambiguity this time. Carole was very close but
several of us got a solid identifiable look.
Alan's hermit thrush of last week was clearly no
fluke. By the time we turn the corner from
Holliston near the end of the walk, we have 23
species, equaling the standing record for week 44
but it's looking like our only hope for breaking
the record lies in seeing a mallard, a thin reed
because the ducks have been highly unreliable of
late. As we come up to Parsons-Gates, however,
we are confronted by a raven thirty feet up,
perched on a wooden throne with his head in
profile, so that we could appreciate his regal
bearing and thick bill. We were officially in
record territory. We didn't hear or see the
Millikan chickadee but, as we approach Millikan,
we see a white pigeon on the lip just above the
reflecting pool. There was no black band on the
neck, so this was probably somebody's homing
pigeon, who had decided not to go home
immediately after some nearby dove release, and
not a white ring-necked dove. Finally, Darren
walks over to the Millikan ponds and quickly pops
up waving two happy fingers at us. We have a
pair of mallards and a final total of 26 species.
Although the western meadowlark qualifies as uncommon, the species
of the day has to be the northern flicker. This
was strictly an acquisition through vocalization
with Darren calling the call and Travis acceding.
Still, you have to take your rare birds where you
get them and we haven't had a flicker for a
while. So, we'll take it.
For some Caltech species, there are clear drifts
in the number of sightings as a function of time.
I discussed our burgeoning turkey vulture
sightings not long ago. Red-masked parakeets
were nonexistent on our walks before 1999 but are
now common during the summer. Before 2003, we
averaged just four lesser goldfinch sightings a
year. Now we get them more often than not.
Northern flickers carry a different story. We
had 28 sightings between 1989 and 1992 but have
averaged just one a year since then. Perhaps,
this was one persistent wintering bird distorting
the ambient flux. Caltech doesn't have a lot of
open scrubby fields or forest edges, favored
foraging habitat for flickers. We also tend to
kill off rambunctious colonies of ants, a favored
food item for flickers (they have a sticky tongue
that can extend ten cm beyond the bill,
comparable to a giant anteater if you scale for
size and yielding a similar result for the ants).
Flickers eat a lot of berries during the winter
and we don't have a terrific supply of those
either. So, you wouldn't expect Caltech to have
a lot of flickers sticking around for extended
periods of time but maybe that just highlights my
inability to channel these birds.
Northern flickers are a good example of the
dangers of taking a set of field markings that
work in one part of the country and applying them
uncritically to another. I was outside my
parents' home in New Hampshire some years ago
(without binoculars) and hear what sounds like a
flicker. I look up and see the bird on a tree
and I'm still thinking northern flicker but then
it decides to fly away and I see an unmistakable
yellow underside to the wings. "Well, this can't
be a northern flicker," I think. "They flash red
under the wings." I wander into the house and
mutter something to my father about seeing some
sort of flicker. My father is not a birder but
he is quite familiar with all the local flora and
fauna and says "Oh, yes. Northern flickers are
common around here." I was for a while bemused.
This was all wrong for a west coast northern
flicker (red-shafted) and I had, without knowing
it, built the red under-wing into my personal set
of diagnostic field markings for this species.
It was, however, just right for an east coast
northern flicker (yellow-shafted). Red-shafted
and yellow-shafted flickers are both
self-respecting northern flickers and I had just
learned about subspecies groups. Their ranges
are separated by a region in the rain shadow of
the Rocky Mountains where they hybridize freely
but there is no sign that the hybrids are
expanding territory relative to either
subspecies. This appears to be a very stable
arrangement. There is some evidence for
declining population overall for northern
flickers and this is worrisome because flickers
are primary hole nesters (i.e., they batter out
nesting holes for themselves, although they are
not above renovating an old hole). A host of
secondary nesters take advantage of flicker
nesting holes and a serious decline in northern
flickers would likely redound in serious losses
for numerous secondary hole nesters due to fewer
available sites. I have seen some assertions
that the flicker decline is due to starlings
driving the flickers away from their nesting
holes. It is at least anecdotally robust that
starlings do this but I haven't seen much in the
way of evidence that this leads in turn to a
reduced fecundity for the flickers although I
sure hope we have somebody out there trying to
find out.
The date: 10/31/11
The week number: 44
The walk number: 1115
The weather: 70°F, mostly sunny
The walkers: Viveca Sapin-Areeda, Carole Worra,
John Beckett, Travis Cummings, Darren Dowell,
Vicky Brennan, Tom Palfrey
The birds (26):
Rock Pigeon
Scrub Jay
Northern Mockingbird
Mourning Dove
House Finch
Anna's Hummingbird
Crow
Red-Tailed Hawk
Yellow-Rumped Warbler
Lesser Goldfinch
Ruby-Crowned Kinglet
Red-Whiskered Bulbul
Cedar Waxwing
Spotted Towhee
Western Meadowlark
American Goldfinch
Northern Flicker
Hermit Thrush
Black Phoebe
House Wren
Orange-Crowned Warbler
Bushtit
European Starling
Hummingbird, Selasphorus
Common Raven
Mallard
--- John Beckett
Respectfully submitted,
Alan Cummings
11/7/11
http://birdwalks.caltech.edu/index.html
10/24/11
We have walker news and walkee news this week.
First, the walker news: Travis was back. That's
two sightings in one year. If he keeps this up,
he won't be a rare bird anymore. We also had two
highlight birds, although highlights for
different reasons. On the down side, there were
no woodpeckers anywhere to be seen and our
black-throated gray and Swainson's warbler power
outage continues. Nevertheless, the walk overall
was very nice with 22 species to light the way,
just a shy of the record 23 for week 43.
See the plots at
http://birdwalks.caltech.edu/bird_data/species_time.html
and
http://birdwalks.caltech.edu/bird_data/two_plots.htm
We picked up another mountain chickadee near the
end of the walk, thanks to Darren's ears. This
bird has apparently been hanging out near Dabney
and the Millikan ponds for several weeks and
we've probably picked him up at three or four
times, although not all of these sightings led to
a new species for the day. We now have five
official chickadee blessed walks for the year and
this compares rather favorably with the sum total
of all chickadee sightings prior to this year
(nine) and to the most chickadee sightings in any
given year prior to this year (two).
The other, and principal, highlight bird was
acquired in the spider jungle of the Maintenance
yard. Alan is working along the eastern fence,
employing his standard spider web defense
strategy when a thrush flushes and flies into the
next yard without providing a lot of clues to
identity beyond the initial flash view. Alan
attempts to entice another encounter by playing
hermit thrush and Swainson's songs but his bird
is not biting. Most wintering hermit thrushes
stake out and defend a ~1/2 acre territory with
calls, so perhaps Alan's offering, as haunting as
it was, failed to meet the "what are you doing in
my yard??!!" threshold. Of course, it's also
possible that the thrush was a floater hermit
thrush (doesn't keep a territory during the
winter and might, therefore, have kept moving in
the wake of a vocal challenge) or one of the
Swainson's thrushes that migrate past us on their
way to Central America, right about now. Tough
call. Now, as you may have inferred, we have
only two American thrushes that venture onto
campus, hermit thrushes and Swainson's thrushes.
All right. I know the smart alecky types are
jumping all over that statement, so I will revise
it to say that we only get two kinds of thrushes
in the genus Catharus on campus. This includes
all the classic birds most people think of when
you say the word "thrush" but excludes American
robins and western bluebirds, which are also in
the thrush family and are also encountered on
campus. Alan, in the meantime, is still wrestling
with identification with the conundrum displayed
in full view below us. He is wrapped in vines
and flipping rapidly between the hermit and
Swainson's thrush pages in his Sibley guide. He
is looking worried, so I think it worth an aside
to say something about classical identification
characteristics of his two competitors. If you
have good light and a good view, it's fairly easy
to tell these birds apart. Our hermit thrushes
have a russet tail that is distinctly different
in color from the more subdued brownish wings and
back (i.e., you will get a sense of two-tones,
although the distinction can be subtle if you
aren't used to it or the lighting is bad).
Coloring of wings and tail for the Swainson's
thrushes are more even toned. Their tails can go
towards the reddish end of the spectrum but, when
they do, you will see a lot of the same russet
off tail. Another clue, if you get a look at the
head of a hermit thrush, is a white eye ring.
The Swainson's also has an eye ring but his will
be decidedly beige as will be the lores, the
feathers between the eye and bill, which, when
put together, gives him a "spectacle" look. An
additional habit-oriented hint is that hermit
thrushes tend to cock their tails when foraging
on the ground and Swainson's don't. From a
purely odds-based perspective, we are much more
likely to see a hermit thrush than a Swainson's,
largely because many hermit thrushes winter here,
whereas all of the Swainson's are in a big hurry
to head south and will only be seen around Caltech
during the Fall for a week or two. Not
surprisingly, we get about nine times as many
hermit thrush sightings as Swainson's thrush
sightings and most of our Swainson's sightings
are from the Spring. There is, however, a "but".
If we get a Swainson's, it's going to be right
around weeks 20 or 41 as they pass by us on
migration. They are nocturnal migrants but they
do move around locally during the day, so we have
a fair shot at seeing one if it's in the
vicinity. Hermit thrushes arrive at Caltech
around week 40-43 in the Fall and leave around
week 20 of the following year. So, if you have a
Catharus thrush between weeks 45 or so and 15 or
so, a Swainson's is completely out of the picture
and any Catharus sighting is pretty much a lock
for a hermit. For week 43, the bottom line is
that a Swainson's thrush sighting is probably too
late but is certainly not implausible unless you
have independent information on exactly when the
current crop of Swainsons' passed through
Pasadena and can say that it already happened.
So, let's return to Alan and his struggles.
After much flipping, and armed with the knowledge
that he will have to create a new category called
"thrush species" if he can't make up his mind,
Alan finally concludes that it must have been a
hermit thrush, the first of the season.
I have a couple of quick hermit thrush factoids
for you. Hermit thrushes eat assorted
invertebrates when they can get them, especially
just prior to migration, but, during the winter,
they also eat a lot of berries. Now, cedar
waxwings, which are obligate frugivores during
the winter, concentrate on fruits with simple
sugars that can be almost instantly converted to
energy. They want throughput to be as fast as
possible so they can maximize input and,
therefore, energy production. Cedar waxwings eat
the berries whole and then excrete the seeds.
Hermit thrushes concentrate on lipid-rich berries
and this requires more work to extract the
energy. Passage through the gut is much slower
than for a cedar waxwing and retaining seeds,
from which you can obtain no nutritional value,
significantly reduces the amount of energy you
can extract per berry consumed. So, rather than
allowing the seeds to spend a lot of time in the
gut doing nothing useful, hermit thrushes spit
them out. Factoid #2 is an ecological trap.
During the breeding season, hermit thrushes
really like the edges of clear-cut forests.
These offer open brushy foraging areas and there
is more food to be had. The problem is that
these areas also come with more predators so that
nesting success is very bad relative to uncut
forest interiors. The ecological trap is set
with attractive baiting but the true cost, which
is not part of the purchase price, is the lives
of all your children.
The date: 10/24/11
The week number: 43
The walk number: 1114
The weather: 66°F, partly cloudy
The walkers: Alan Cummings, Travis Cummings,
Darren Dowell, John Beckett, Vicky Brennan,
Viveca Sapin-Areeda
The birds (22):
Rock Dove
Scrub Jay
Mourning Dove
House Finch
Anna's Hummingbird
Crow
Mallard
Yellow-rumped Warbler
Red-shouldered Hawk
Black Phoebe
Lesser Goldfinch
Hermit Thrush
Yellow Chevroned-winged Parakeet
Cedar Waxwing
Red-Tailed Hawk
Orange-Crowned Warbler
House Wren
American Goldfinch
Hummingbird, Selasphorus
Ruby-Crowned Kinglet
Bushtit
Mountain Chickadee
--- John Beckett
Respectfully submitted,
Alan Cummings
10/30/11
http://birdwalks.caltech.edu/index.html
10/17/11
We got 25 species, which is a fine day's calling
for most any week and well above the median of
15. Usually, with a score of 25, I would now be
launching into a self-congratulatory discussion
about our new record and how we got there. The
record high species count for week 42 is,
however, an extraordinarily high 29, which was
set last year, shattering the previous record of
21. If it were 26 or 27, I might grouse about our
not seeing any black throated gray or Townsend's
warblers this week but picking up another four or
five birds would have required more than catching
a couple of breaks. So, I think I'll leave the
monster 29 alone and point out that opportunity
is on the way. For each of the next three weeks,
the record is 23.
See the plots at
http://birdwalks.caltech.edu/bird_data/species_time.html
and
http://birdwalks.caltech.edu/bird_data/two_plots.htm
What we didn't have in raw numbers to put up
against the record we more than made up for in
rarity. We didn't see another chickadee but, as
we come up to the playing field after exiting the
Maintenance yard, we do our usual scan across the
baseball field from behind the fencing. We soon
see a meadowlark near a bench that had been
placed on the field for some reason. The bird
initially shows us only the classic profile of a
meadowlark but, eventually, he turns and we can
see the front with a classic black loop and
strong post-molting yellow breast. There was no
doubt about the identification, even in a few
seconds of long-distance observation. A
meadowlark is a very good capture for us but we
average about one a year (i.e., this is a 2%
probability bird) with almost all of the
sightings between weeks 39 and 45. This sounds
strange because there is no Spring component at
all, but there you have it. We were quite pleased
with our meadowlark.
Perhaps 20 meters north of the meadowlark, a
small sparrow-sized bird was hopping around.
Alan thought it might be a lark sparrow or
something in that general genre. I thought a
lark sparrow didn't seem right but I had
absolutely no clue what it might be other than
odd and, given our complete lack of sparrows for
the day and our general lack of success in
acquiring sparrows in recent weeks, it seemed
likely that this was going to be a desirable
bird. Now, given our position along the driveway
a definitive answer for the species would have
taken a spotting scope, which we didn't have, but
there was also clearly a species to be had that
we didn't have. So, Alan asks for a volunteer to
make a special field trip to identify our mystery
bird and Darrell offers to go. Melanie, who
didn't have anything as funky as a lark sparrow
on her life list, decides to join him and the
rest of us proceed towards Tournament Park with a
stop at the track, which yielded yet another
meadowlark.
It didn't take long. Darrell and Melanie
intersect us at the gate going into Tournament
Park with Melanie looking excited and Darrell
looking like the proverbial cat who swallowed the
canary. Darrell was also carrying a camera that
was absent when the D & M expedition had set off.
So, I sensed something big and I wasn't
disappointed as Darrell announces that we had an
American pipit. Once he had realized that there
was a pipit in the offing, he had run back to his
office to get his camera and had managed to take
some pictures. One glance was completely
convincing, as American pipits are very
distinctive looking birds. We had an American
pipit!
Our previous pipit sightings have all occurred
between weeks 38 and week 1 of the following
year, so our new sighting in week 42 is
consistent with this pattern. If, however, you
look at Alan's database for the Caltech birding
walk, you will find no entry at all for an
American pipit although we have five previous
sightings of water pipits, the most recent in
1998. With just six pipit sightings, it's safe
to say that pipits of any description are quite
rare for us (half a per cent level occurrence).
Does the absence of an American pipit entry in
Alan's database mean that we have a novel new
species to add to the list? Do we have specific
species number 120 for the Caltech bird walk?
Unfortunately, the answer to that one is no and
the resolution of why is a testament to the
metrics of hard taxonomic work and DNA. In the
olden days, the days before DNA, there were
various subspecies of water pipits (Anthus
spinoletta) in North America, Asia, and Europe.
Even then, clues like an extremely high
infertility rate for human sponsored attempts at
the breeding of European and American water
pipits, suggested that this cozy inclusive
collection of subspecies might not be sound. By
the late 1980s, it had become clear on both
taxonomic and DNA grounds that all of the North
American and east Asian water pipits were
actually members of one of the various subspecies
of American pipits (Anthus rubescens) (i.e., all
of our water pipits are American pipits not
American water pipits). The American
Ornithologist's Union, which keeps tabs of such
things, made it official in 1989 (see Monroe et
al. (1989) Thirty-seventh supplement to the
American Ornithologist's Union check-list of
North American Birds. Auk volume 106, pages
532-538, which you can access through JSTOR, if
you are interested). So, if you want to bag a
real water pipit for your life list, you are
going to need a plane ticket and a passport. It
looks like Alan is going to have to update his
database to transform all of his water pipits
into American pipits. That's ok, although it's
extra work for Alan. I'm sure the pipits will
all be much happier. Of course, if Alan
remembers seeing some water pipits in Europe, he
also gets to add a new bird to his life list
instead of just relabeling an old one.
As an aside about the unintended consequences of
human activity, I offer an intrepid explorer who
decides to study the breeding behavior of (then)
water pipits on the tundra (pipits are ground
nesters in the tundra of the arctic and in high
alpine meadows to the south, including those on
Mount San Gorgonio and in the Sierras). After a
few hours of careful observation, our
investigator has located some nest sites and
places a surveyor's stake with a bright orange
flag next to each. He then retires to his
observation post and is feeling pretty good about
how the day's work is going. However, many a
pride hath fallen to the observational skills and
opportunistic foraging techniques of ravens. A
raven happens to fly by the field area and
notices the surveyor posts with their flapping
orange flags. "These are very strange looking
things", says the raven to him self. "I'd better
investigate." So, he flies over to one of the
posts and walks around. Almost immediately, a
female pipit flushes (the females do all of the
incubation), revealing a nest full of eggs, which
the raven proceeds to eat. "Well," says the
raven, "that was tasty. I think I'd better
investigate the next post." So, he does. By the
time our investigator manages to reconstruct the
raven's thought process and pull his stakes,
several flagged nests have been destroyed. He
had the honor of discovering that flagging food
for a raven gets you a 100% predation rate and
that, in a contest between a graduate student and
a raven, the graduate student has a severe
disadvantage if the raven cares at all about the
result. It was raven 20, investigator zero,
future young pipits dead.
The date: 10/17/11
The week number: 42
The walk number: 1113
The weather: 81°F, sunny
The walkers: Alan Cummings, Melanie Channon, John
Beckett, Viveca Sapin-Areeda, Darren Dowell,
Hannah Dvorak-Carbone
The birds (25):
Rock Dove
Northern Mockingbird
House Sparrow
Mourning Dove
House Finch
Anna's Hummingbird
American Crow
Downy Woodpecker
Yellow-Rumped Warbler
Orange-crowned Warbler
White-throated Swift
Lesser Goldfinch
Red-whiskered Bulbul
House Wren
Yellow-Chevroned Parakeet
Western Meadowlark
Common Raven
American Pipit
Cedar Waxwing
Hummingbird, Selasphorus
Say's Phoebe
Black Phoebe
Ruby-crowned Kinglet
Nuttall's Woodpecker
Bushtit
--- John Beckett
Respectfully submitted,
Alan Cummings
10/21/11
http://birdwalks.caltech.edu/index.html
10/10/11
It was an excellent birding day. The conditions
were pleasant and we ended up with 24 species, a
total that included four warblers, a mountain
chickadee and a Say's phoebe among the many
highlights. Still, it could have been better and
I am not afraid to sow a song of sorrow on a
field of joy. There were white-throated swifts
swirling around Millikan at 10 AM but not at
noon. There are starlings and rock doves sitting
on the Millikan roof at 5 PM but not at noon.
Last week we got a band-tailed pigeon, red-masked
parakeet, and a mockingbird but none of them
showed up this week. Enough complaining about
the birds that weren't. This was a first rate
walk for week 41. With 24 species, we tied the
record, which was set last year, and we were
three ahead of any other year (i.e., our 24 would
have meant a substantial increase in the record
had it not been for last year). We are beginning
to accumulate all sorts of indications that this
is an unusual year for the walk. For example,
this week brought our eighth report of a turkey
vulture for the year. Only 2008, with 11, can
boast a higher sum. The mountain chickadee gave
us four for the year, double that of any previous
year and nearly half as many as the sum of all
sightings for all previous years (nine). We are
matching up well against last year's Fall
migration, which was stellar, and this bodes well
for our walks over the next few months.
See the plots at
http://birdwalks.caltech.edu/bird_data/species_time.html
and
http://birdwalks.caltech.edu/bird_data/two_plots.htm
Hannah brought in the first yellow rumped warbler
of the season. While at the north end of the
maintenance yard, Hannah was pretty sure that she
had heard a yellow rump but the other great ears
of the group were not nearby, so we were lacking
confirmation, and we weren't able to locate the
bird for a visual. It was looking like we
weren't going to be able to claim it but the bird
suddenly decides to fly out of deep cover and zip
off to the northeast. He was moving fast and
lost to sight in three seconds but not before we
saw an unmistakable yellow circle on his rump.
We were in business with the first official
yellow rumped warbler of the season.
I think that nothing can replace the satisfaction
of a first capture after months of absence. Yes,
there may be more excitement with seeing a
particular species for the first time but this
doesn't carry the slow build up of missing what
you know and what seems to be just right. In the
weeks leading up to a first Fall migration
appearance, I find myself seeing the ghosts of
Spring in favored spots. I look at branches and
twigs that were alive with warblers just a few
months ago but not now. I still can't help
looking up from the Maintenance Yard at the
quadrant of sky that yielded a Swainson's hawk
last March. To quote Darren, "I would love to
see a Swainson's hawk right now" and, perhaps, I
should offer up a locust to the god of migration
(Swainson's are basically big insect eaters
except during the breeding season when they
concentrate on a more "normal" diet of rodents
and reptiles).
Usually, we see a yellow rumped warbler a week or
more before we see a ruby crowned kinglet (13
years out of 22, with six years yielding both on
the same walk) but in those few years that we get
a ruby crowned kinglet first, we have always seen
a yellow rumped warbler the following week.
This year was no exception. We caught a ruby
crowned kinglet last week. So, this week had to
be yellow rumped warbler time. After Hannah's
initial catch, we saw several yellow rumps or
butter butts as they are sometimes affectionately
referred to. The butter butt clan is definitely
in town.
Not long after Hannah picked up that all
important yellow rump, Darren's ears pricked up
to the call of a black-throated gray warbler. I
was a little surprised as we see Townsend's
warblers in that location somewhat commonly but
black-throated grays are unusual. At first, this
bird was obscured by foliage but he gradually
worked his way towards us and, eventually, we
were watching a male warbler from as little as 5
meters away. It was probably the second best
viewing of a black-throated gray in my life (the best
one was in Upper Newport Bay when two males
landed on a small branch a meter away from my
head and almost at eye level; everybody froze for
about 30 seconds). Usually, these birds are
higher up in the canopy and, although the views
may be nice, they aren't spectacular. This
qualified as spectacular. You could see the
speckling in his little black throat.
The first black-throated gray, which I described
above, was not working through an oak canopy,
although the Maintenance yard does have some.
Wintering black-throated grays are highly partial
to coast live oaks. We have a fair number of
oaks on campus, including live oak, Engelman's
and at least one valley oak, but our oak trees
are generally isolated or arranged in short
linear arrays that aren't super attractive. We
have, however, one excellent stand of mature oaks
at the south end of Tournament Park. We
occasionally pick up black-throated grays in
other spots, as we did this week, but I would
guess that the vast majority of our sightings are
in Tournament Park and the bulk of these come
from the small oaky area at the south end
including a couple of birds this week.
Darren also caught a Townsend's warbler preening
in plain view at the north end of Tournament
Park. Some of us, including me, had a tough
frustrating time finding the bird because we were
looking at the wrong tree. Townsend's are not
usually patient sitters and are often moderately
high up in the canopy. Once I finally got to him
though, the frustration oozed away. He had
waited for me and he was worth the effort.
Darren, however, wasn't done. We had spent so
much time working Tournament Park that Darren
broke off from the walk when we got back to
California Blvd. We cross the street, thinking
that Darren was gone for the day but he suddenly
reappears in our midst on the north side of the
street and announces that he had just seen a
Say's phoebe on the fencing as he was walking
back! It is often said that it is better to be
lucky than to be good but it seems that Darren
was taking a full swig of both this week.
I find it odd that there are so many different
warblers with such different plumages and songs
encompassing such limited environmental niches.
Take this walk as an example. We have three
Dendroica warblers (Townsend's, yellow-rumped and
black-throated grays; orange-crowned warblers are
in the genus Vermivora). This week, all three
Dendroica species were operating within 30 meters
or so of each other. Yet none of these species
are interbreeding significantly (hermit warblers
and Townsend's have been getting together). Why
aren't they all doing it? The plumages may be
wildly different but the basic morphology of one
Dendroica warbler is not that different from the
next and yet this one genus of warblers has 29
species (half of the warbler species in the
country). In the beginning, the answer seems to
be in the desert. Towards the end of the Miocene
and in early Pliocene times, about 4 or 5 million
years ago, the U.S. became increasingly arid, so
much so that many of the large mammals of the
time went extinct. Forest stands became isolated
and Dendroica wood warblers experienced a
"sudden" burst of speciation as they took on a
variety of specialized environmental niches
(adaptive radiation). These birds tend to forage
in different places and/or at different levels in
tree canopies. Black-throated grays are most
frequently in oak at mid- to high levels in the
canopy. Townsend's are a little more
cosmopolitan and yellow rumps will try just about
anything but can commonly be found working
through bushes or even on the ground. There is
some overlap, especially during the nonbreeding
season, but there is remarkably little direct
competition. Each Dendroica warbler knows where
he wants to be and, by and large, that doesn't
happen to be where another Dendroica species
wants to be.
The date: 10/10/11
The week number: 41
The walk number: 1112
The weather: 76°F, partly cloudy
The walkers: Alan Cummings, Hannah
Dvorak-Carbone, Darren Dowell, John Beckett,
Viveca Sapin-Areeda, Vicky Brennan
The birds (24):
Scrub Jay
House Finch
Anna's Hummingbird
Acorn Woodpecker
American Crow
Lesser Goldfinch
Black Phoebe
Red-Tailed Hawk
House Wren
Nuttall's Woodpecker
Spotted Towhee
Black-throated Gray Warbler
Yellow-rumped Warbler
Orange-crowned Warbler
Townsend's Warbler
Bushtit
Ruby-crowned Kinglet
Red-shouldered Hawk
Hummingbird, Selasphorus
Bewick's Wren
Say's Phoebe
Common Raven
Turkey Vulture
Mountain Chickadee
--- John Beckett
Respectfully submitted,
Alan Cummings
10/14/11
http://birdwalks.caltech.edu/index.html
10/3/11
It was looking a little bleak. In spite of a
fairly impressive contingent of birders, we had
only a dozen species to show for our efforts by
the time we reached the northeast end of the
campus. It is true that we were safely above the
lowest species score of eight for week 40 (it's
12 next week) but we were also well below the
average of 15 and not even half way to the record
of 25. Where were all the birds that are
supposed to appear around week 40? We did have
one, a ruby-crowned kinglet that I discuss below,
and, if the orange-crowned warbler was not a
Channel Island bird, perhaps two. I am expecting
a more migratory cadence next week because a lot
of Canadians and Alaskans should be riding the
jet stream south and this week boasts the first
storm system of the season to push down the
coast. So, I can rationalize why the big
migration may not have hit us yet but we were
also weak on Alan's standard check list birds.
We had only four of nine. We had no accipiters,
woodpeckers, or sparrows of any description.
Still the walk had numerous highlights. One of
these came towards the end of the walk as we were
passing through the garden north of Avery.
Melanie suddenly stops short with the realization
that she is hearing bushtits calling from behind
her. So, we turn around and walk back towards
the big oak that dominates one end of the garden.
At first, there is no motion beyond a few zephyrs
lightly teasing the leaves but as we reached and
began to walk beneath the canopy of the oak, a
little gray puffball with a long tail zips by,
soon followed by several more. We had Melanie's
bushtits. Now, you may think this is not a big
deal. After all, identifying bushtits by sound
and/or sight happens all the time but, to me, it
was like watching a bird fledging. There is a
complexity in the receptive interplay of hearing
a call, or in this case a lot of calls, and
placing it in the context of time, place,
habitat, and species. You know you want to fly
and you grasp the general concept but when do you
make that first great leap into the void?
Melanie knew that she had heard a bushtit and was
willing to say so. She had made the aural leap
to identification through nothing more than a
vocalization and she had an expressive confidence
in that identification. She knew where to
investigate for a possible visual, so she was
developing a directional focus. She knew a
bushtit when she saw it. Even better. In the
past, she might have heard something somewhere
out there and then looked for something with
feathers on it somewhere in the general area.
Maybe it would work and maybe it wouldn't.
Mostly, it didn't. Now, Melanie has a
vocalization locked in and a sprouting sense of
direction. No doubt, there are going to be some
awkward landings in the future. So what? It was
one bird down and a few hundred or, perhaps, even
thousands of different vocalizations to go (and
then, of course, there is the regional dialect
issue).
Melanie's bushtits brought us to 13 for the walk.
We added a turkey vulture soaring high above the
campus and a Selasphorus hummingbird on one of
the Holliston silk floss trees to round the
species count up to a more or less respectable
15. This ties the average for the week.
See the plots at
http://birdwalks.caltech.edu/bird_data/species_time.html
and
http://birdwalks.caltech.edu/bird_data/two_plots.htm
In the beginning, it was a sound and Alan, whose
birding ears have drawn to this siren call
before, immediately declared the presence of a
kinglet. We had an instant bird of the day if we
could just find it, not that we didn't trust Alan
but, well, it would be really nice to get a
visual just to be sure. Soon we were following a
bird foraging actively through an oak but it was
coy and, somehow, not quite right. Gradually, we
acquired bits of bird and it was, not only not
quite right, it was unambiguously not right at
all. We had several solid visuals on an orange
crowned warbler. This bird doesn't sound
anything like a kinglet if he's inclined to
speak, which this bird apparently was not. Could
Alan have mistaken this bird for a kinglet? Were
we about to enter a crisis of faith? Could Alan
be right but the bird gone, leaving us with a
longing mystery built of hope and expectation?
Nope. A second bird was foraging just a few
meters away from the warbler. Frenetic activity
with lots of wing flicking - check. Taupe body -
check. Prominent eye ring - check. Sharply
defined wing bar with dark underlining - check.
Alan's ruby-crowned kinglet - check. Alan had
seized the day and brought the season home.
To me, the arrival of ruby-crowned kinglets is
one of the two great markers of the season's
turning, yellow-rumped warblers being the other.
A kinglet's passing meals may have more subtlety
than the garish blot on a calendar announcing
some tangential shift in an astronomically
defined continuum and it may seem a lot more
capricious but the Fall migration is as primal as
a mother singing to her child. She captures the
blessing born in each holding note, caressing the
vocalization like a wayward tuft of hair. This
is a tangent sharing that is fundamentally
conjoined and we, whether we acknowledge it or
not, are also conjoined.
Our kinglet is almost certainly a first year bird
as first years lead the migration south, followed
by adult females and, finally, the males. There
was a time when you could not have said this
because of an active breeding population in the
San Gabriel Mountains that would drop down into
the lowlands for winter. However, the local
residents have all died out and our winter
visitors now come from northern parts of the
state and points north. For us, the probability
of seeing a ruby-crowned kinglet rises sharply
from week 39, the earliest recorded Fall arrival
(1990 and 1992), until mid-November or so, when
everybody who wants to be in town with us is with
us and those who prefer to be in Mexico have
moved along. Our kinglets will stay until about
week 14 of next year (plus or minus a couple of
weeks).
In other not so good news, we saw a cat, likely
feral, scooting around the Maintenance yard. She
was looking for lunch, be it bird or lizard, and
looking like she needed one. She was not at all
happy about our being there. Indoor-outdoor and
feral cats are a big problem for ground foraging
birds like sparrows, towhees, and, especially,
hermit thrushes. The resident locals probably
know all about this cat and her hunting routines
but the migratory birds are vulnerable.
Finally, since I am on the subject of cats and
kinglets, I will give you a little story. One
day, during the winter of our cat Gentille's
first year with us, I notice her on the bookcase
in the den watching a ruby-crowned kinglet
working through a lemon tree just outside the
window. This is cat TV at its best, I thought,
but I was wrong. The bird suddenly flits over to
the windowsill and Gentille can't stop herself.
She lunges at the kinglet banging her paws
against the window. Instead of flying away,
however, the kinglet flicks his wings and starts
hopping on the windowsill right in front of
Gentille, red crest, which is only visible on
these birds when they are excited and only
present on the males, blazing away. His wings
are constantly flicking and fluttering. Gentille
watches this performance in amazement for a few
seconds and then starts muttering. She tries
another half-hearted poke with her paw but
finally decides that this bird can't be touched.
He's very real but he can't be touched. I thought
Gentille was going to find a way to ignore the
kinglet, either by leaving or turning her back on
him and pretending he wasn't there, but she is
fascinated. She watches the entire performance,
perhaps twenty seconds, until the bird decides to
go back to foraging. Now, this might have been
chalked up to a curiosity and not worthy of
relaying to you but the kinglet stayed with us
all winter and gave many windowsill performances
for Gentille, both in the den and in the dining
room. I saw him, on numerous occasions, fly
directly from a foraging site over to a
windowsill in front of Gentille and do his little
dance. The bird clearly understood what the
window was and knew what the cat was. I'm
confident that he wasn't foraging on the
windowsill, first because that's not a normal way
for kinglets to forage but also because he would
never use more than the few inches right in front
of Gentille's nose and never went to the
windowsill when Gentille was not there. He was
thumbing his beak at death and dancing life. As
far as I know, Gentille never tried to bat him
again but she always stayed through the kinglet's
entire performance. The best show in town was a
ruby-crowned kinglet who could dance. The
kinglet came back for encore performances the
following winter, always finding time to
entertain Gentille. I found this a little odd,
actually, because wintering kinglets usually
don't return to exactly the same territory but
maybe he liked Gentille. In the third winter,
however, we didn't see him, although I'm quite
sure Gentille remembered and, perhaps, even
expected an appearance.
The date: 10/3/11
The week number: 40
The walk number: 1111
The weather: 79°F, partly cloudy
The walkers: Alan Cummings, John Beckett, Melanie
Channon, Vicki Brennan, Carole Worra, Kent
Potter, Tom Palfrey, Viveca Sapin-Areeda
The birds (15):
Northern Mockingbird
House Finch
Anna's Hummingbird
Crow
Black Phoebe
Lesser Goldfinch
Common Raven
Red-tailed Hawk
Orange-Crowned Warbler
Ruby-Crowned Kinglet
Band-Tailed Pigeon
Red-masked Parakeet
Bushtit
Hummingbird, Selasphorus
Turkey Vulture
--- John Beckett
Respectfully submitted,
Alan Cummings
10/7/11
http://birdwalks.caltech.edu/index.html