It's nice to see that I'm not the only one who noticed that the native
trees and shrubs in the Valley leafed out earlier than usual this spring
(and late winter, in some cases). My guess is that our unusually mild
winter and typical rainfall were the driving factors. Whether that was
ultimately was due to a normal El Nino event, a more troubling long-term
pattern, or a combination of both is for somebody else to decide.
Brandon
Eugene
On Fri, May 27, 2016 at 1:00 PM, Joel Geier <joel.geier@xxxxxxxx> wrote:
On Fri, 27 May 2016 04:59 Leith McKenzie wrote
Given the [low] ratio of detection of rarities to birder talent hours
currently being expressed in Eastern Oregon, are we witnessing a
fundamental shift in the patterns of bird behavior. FYI, it seemed
that this was the case on Skinner's Butte in Eugene this spring - it
seemed as if the majority of migration had passed us by far earlier
than usual.
Leith (Maitreya?) I'm loathe to ascribe too much significance to vagrant
records, for a couple of reasons:
1. By definition vagrants are "statistical outliers" in terms of range,
so we're trying to glean information from the "noise" in the signal.
2. Vagrants tend to have longer migration routes than other migrant
birds, so their timing of arrival can be affected by more perturbations
along the way.
What we see in Oregon is effectively the "integral" of all of those
perturbations along the paths that they followed, depending on the
timing of events. Those paths can be far more complicated than we'd
guess. For example, consider this article on "tornadic storm avoidance"
by Golden-winged Warblers:
http://www.cell.com/current-biology/abstract/S0960-9822%2814%2901428-6
But I think we're on better ground when we talk about the timing of more
expected birds, such as our regular nesting sparrows, warblers, and
empids as you mentioned.
Here are a couple of things that I've noted this month:
(1) Barn Swallows were visiting regular nesting sites around Corvallis,
and reached full numbers at those sites about one to two weeks earlier
than usual.
(2) White-crowned Sparrows nesting at Luckiamute State Natural Area set
what seem to be all-time Oregon records for early egg dates and early
fledging -- with at least two broods involved and likely more, so not
just one outlier event.
(3) All of our native trees -- cottonwoods, maples, oaks, ash, etc. --
leafed out about 2 weeks earlier than would have been typical 15 to 20
years ago.
(4) Down in the Umpqua Valley, many farmers around Sutherland had
already baled their first crop of hay by May 16th -- that seems early
compared with when I started running a BBS route there about five years
ago, and balers were active on what looked like the first hay crop
around the 10th of June.
Regarding California (as Brandon Green brought up), at least the
northern half of the state which I drove through last week seems to be
in a more typical state following the years of drought.
Grasses on the hillsides of the inner Coast Ranges are turning golden
but that's normal by this point in May. When I took my first field
geology course at UC Berkeley during the spring term about 35 years ago,
we used this tendency as a handy tool for remote mapping of contacts
between different formations.
There are still quite a few wildflowers blooming and riparian areas are
more lush than they've been in recent drought years. I must have heard
15 or more Pacific-slope Flycatchers singing in the Berkeley Hills in
the space of half an hour, just by driving through with my windows
rolled down. I found both Hooded and Bullock's Orioles without any real
effort.
Coast range creeks and rivers still have robust flows. Nearly all of the
acreage of the rice farms of the Sacramento Valley is flooded, though I
did notice a few paddies that had been left dry, perhaps 1 in 10, which
might indicate that farmers are hedging their bets on water
availability.
So overall my sense is that the habitat for migrant birds passing
through northern California is in fairly good shape. Perhaps the
situation in southern California is different. Farther north in Oregon,
many nesting birds and key components of their native habitat seem to be
well ahead of schedule.
Good birding,
Joel
--
Joel Geier
Camp Adair area north of Corvallis
