ma4cc@sdcc3.UUCP (Tim McLarnan) (02/16/85)
I haven't any field trips to report on at the moment,
but I thought people might be interested in a couple of
observations on hummingbird behavior I've made in the last
few days.
While everyone else seems to be seeing Snowy Owls, we
in Southern California are starting into the height of the
nesting season (which really lasts most of the year) for
Anna's Hummingbirds. About 10 days ago I first noticed a
female Anna's here on the UCSD campus collecting nesting
material (dandelion seeds). Typically, however,
hummingbirds seem to forage for nesting material some
distance from the nest itself, then to disappear at high
speed and be lost to a casual observer. As a consequence, I
was unable to find the nest under construction.
A day or 2 after this, I witnessed one of the strangest
territorial confrontations I have seen between these
pugnacious little fellows. A male Anna's had settled onto a
bare patch of dirt outside a university building. The
irridescent red feathers of its gorget and forehead were
flared out, and it was calling vigorously. As I watched, a
second male dropped onto the ground facing the first at a
distance of about 8 cm. Since hummingbirds have only very
short legs, the 2 birds were not standing, but simply lay on
their breasts in the dust. Both flared their gorgets and
called. This curious standoff lasted for perhaps 30 sec.
before finally one bird flinched and took off. A vigorous
aerial chase ensued, and I lost sight of the combatants.
Has anyone else observed this type of thing? I don't
believe I've ever before seen a hummingbird lying on the
ground, and I've certainly never seen this sort of
terrestrial shouting match. Anna's in general are, however,
very aggressive birds. I once watched one calling loudly in
hot pursuit of a Northern Harrier. The hawk did not express
much concern.
Today I finally spotted the first Anna's nest I've
found this season. As is usually the case, I found it by
accident. I was picking up feathers from a juvenile
Red-tailed Hawk which had been dismembered by some unknown
predator, when I became aware of a female hummingbird
hovering around me. She would fly toward me, hover a moment
as close as a meter from me, then land on a nearby twig only
to repeat the process. I realized at once I must be close
to a nest, and set about carefully looking over the branches
of the Eucalyptus tree in front of me. The nest turned out
to be about 3 meters from my head, and less then 2 meters
off the ground. It was the usual tiny cup atop a branch, so
well concealed that even as I reached up to pull the branch
toward me I was unsure whether it was a nest or just a
spot where a branch had broken from the tree. A nest it
was, however, incredibly carefully cemented together and
lined with the tiniest and softest seeds. It is almost
impossible to imagine how tiny and delicate these nests are
without having seen one. A complete clutch of 2 elongate
oval eggs had already been layed. After only a moment's
glance I could no longer stand to upset the mother further,
so I retired at once to let her return to her nest.
I'll keep an eye on this nest from a safe distance over
the next couple of weeks. If people where there is not much
nesting behavior to observe this time of year are
interested, I'll let you know how our young mother succeeds.
_________________________________________________
Tim McLarnan
Dept of Mathematics, UC San Diego
..sdcc3!ma4cc