[obol] Re: Spring Arrival Dates: Long and likely annoying for some
- From: Brandon Green <brandon.green18@xxxxxxxxx>
- To: David Irons <llsdirons@xxxxxxx>
- Date: Fri, 25 Apr 2014 05:22:13 -0700
Dave,
Let's go back and look at what I originally said: "It's likely that at
least a few have crossed the border by now [April 24th]. Still seems early
for Northwest Oregon, but maybe not unprecedented." I was referring to a
few individual outliers that have *just recently* crossed the border into
Oregon. I was not implying that a significant number of Swainson's
Thrushes have been hanging out in the Willamette Valley since the middle of
the month.
If you find the above to be controversial, we'll have to agree to disagree.
-Brandon
On Fri, Apr 25, 2014 at 12:33 AM, David Irons <llsdirons@xxxxxxx> wrote:
> Brandon,
>
> For more than a week now (since at least the 16th of April) there have
> been almost daily reports of Swainson's Thrushes showing up on OBOL and in
> the daily eBird rare bird alert for Oregon. I believe that every single one
> of these reports is suspect. I looked at the eBird map that you provided
> for all-time April reports of Swainson's Thrushes. It covers many years and
> has several clusters of reports that are highly questionable. That said,
> there are some from observers who none of us have any reason to doubt.
> These reports, seem to be clustered (for the most part) over the last few
> days of April (27th-30th). I consider any report in April to be early and
> any report before about the 25th of April to be exceptionally so. We can
> argue over how to define "exceptional," but that's really not the point.
>
> We go through this exercise every Spring on OBOL. The fact of the matter
> is this, not that many birders pay close attention to spring arrival dates
> and if asked many could not tell you when Swainson's Thrushes, Yellow
> Warblers, Warbling Vireos, or Willow Flycatchers normally arrive in the
> Willamette Valley. Without an understanding of spring migration phenology,
> one is unlikely to apply much rigor or objectivity to what they think they
> are seeing because they have no reason to. If you believe what you are
> seeing is normal, why would you question it? If on the 20th of April you
> see a bird that looks like a Swainson's Thrush (the default w. OR thrush in
> the minds of many Oregon birders) and you don't think or know that a 20
> April Swainson's Thrush is unusual, would you be skeptical about your own
> observation?
>
> If you look around the OBOL 'room,' the folks who view these early
> Swainson's Thrush reports with skepticism are folks like Jeff Gilligan–Jeff
> has been birding in Oregon for 50+ years; Tim Rodenkirk–Tim goes birding
> almost every day, keeps a very detailed database on the comings and goings
> of birds in Coos and Curry counties. Tim can authoritatively answer almost
> any question about the abundance, distribution, and seasonality of birds in
> these counties, I know because I regularly ask him such questions; Wayne
> Hoffman–Wayne has been birding in Oregon for decades and has been a very
> active birder since at least the 1970's); Mike Patterson–Mike has been
> birding in Oregon since the early 1970's (at least). He has been the Oregon
> CBC editor for *North American Birds *for about two decades and he has
> been banding along the Oregon coast (Swainson's Thrush central) for 11
> years. These are birders who have been to this rodeo. We've all encountered
> out of season reports of Swainson's Thrushes made by folks who were
> absolutely certain of what they saw. Swainson's Thrush gets reported on an
> Oregon CBC every year. Hermit Thrush is the only *Catharus *thrush that
> regularly winters in Oregon, whereas Swainson's is a mega-rare bird here in
> winter. Swainson's also get reported somewhat regularly in late March and
> the first 2-3 weeks of April, when Hermit Thrushes are the default thrush
> in western Oregon.
>
> Ever since I started birding seriously, I have paid particularly close
> attention to migration/arrival/departure dates. Back in the mid-1980's
> David Fix, Steve Heinl, and I shared an apartment at the base of Skinner's
> Butte in Eugene (3rd and Pearl). During spring migration, we birded the
> Butte every single day, often making more than one trip up the hill per
> day. At the beginning of every season, we would make our predictions for
> the exact day each neotropical species would first appear on the Butte. We
> were rarely off by more than a couple of days. As the years passed and our
> sphere of "young guard" birding buddies grew to include Matt Hunter, Dennis
> Rogers, Rob Fergus, David Bailey and Jim Johnson, this game only
> intensified. We all started each spring migration on a mission to find as
> many "first of the season" birds as we could. If there were mid-April
> Swainson's Thrushes to be found, I dare say one of us would have found
> them. I'm pretty certain that I've never seen a Swainson's Thrush earlier
> than 3 May (and I was surprised by that one). Since those early days, I've
> done a couple of stints writing field notes for *Oregon Birds *and I've
> been Oregon's Regional Editor for *North American Birds *since 2003. In
> order to write these columns, one has to be intimately familiar with
> migration phenologies.
>
> There are two additional phenomena that are somewhat universal in the
> birding world. One might be described as "me tooism." The other is the
> tendency to embrace oversimplified one-size-fits-all explanations when it
> comes to explaining early or late reports.
>
> Me Tooism -- Once a bird is reported by a seemingly trustworthy observer,
> it is as though a permission slip has been issued to the rest of the
> birding community. If an early report of say a Swainson's Thrush or Willow
> Flycatcher is posted on OBOL, you can almost predict a number of "me too"
> reports in subsequent days. "If birder X is reporting one, they must be
> around."
>
> Oversimplified Explanations -- This season's example is the combination of
> drought in California and the stretch of unseasonal warm and sunny weather
> that we enjoyed during the first two weeks of April. At some point there
> was some chatter on OBOL about birds arriving early in California and that
> the drought and nice early April could explain some surprisingly early
> reports in Oregon. Again, another permission slip was issued. A smattering
> of early arrivals occur every spring migration. What we've seen this year
> can hardly be considered an anomaly. Also, the generally poor understanding
> of phenology among rank and file birders leads to birds being reported as
> "early" or "late" even when they aren't. There were questions about the
> first Hammond's and Dusky Flycatchers on Skinner Butte. These two species
> show up every year by the 15th of April, often a few days earlier. This
> spring there have been a few species that have shown up 2-5 days earlier
> than the normal FOS reports. However, aside from the flurry of Swainson's
> Thrush reports and the likely incorrect report of a Willow Flycatcher from
> Detroit Lake, I can't think of any reports that I found to be shockingly
> early.
>
> The California drought and warm spell probably shouldn't be offered as a
> the reason for multiple Swainson's Thrushes being reported between the 15th
> and 20th of April (at least two and more like three weeks early). If you
> look into the points of origination, the migration routes, and the timing
> of spring migration for the many neotropical species that pass through
> Oregon in the Spring, you'll realize that a single factor like the
> California drought, or the period of nice weather we had in April is
> unlikely to have had a wholesale effect on the entire suite of neotropical
> migrants. Some birds start in the desert southwest, some start in Mexico
> and Central America, and others come from as far away as South America. The
> routes taken to reach Oregon do not follow a single pipeline running
> straight up through California.
>
> Approximately three full months pass from the date when the first Rufous
> Hummingbird (the earliest neotropical migrant) reaches the southern Oregon
> Coast, to the date when the first Common Nighthawk (the latest neotropical
> migrant) arrives in the Siskiyou Mtns. and the southern reaches of Oregon's
> Coast Range. When they left their wintering grounds, these birds could not
> have known that they would encounter drought conditions in central
> California, or that a 10-14 day stretch of really nice weather would occur
> in Oregon during early April. In reality, these comparatively local
> climate/weather anomalies probably didn't alter the path or the timing of
> the migrations for most species. Perhaps the early wave of Western
> Kingbirds that we had might be attributed to birds finding no food in
> California's drought-stricken Central Valley and continuing to push north,
> but it's hard to know. Most of the other species that typically show up in
> the first half of April (Hammond's Flycatcher, Pacific-slope Flycatcher,
> Cassin's Vireo, Nashville Warbler and Black-throated Gray Warbler) appeared
> on schedule. In recent days, there have been ever so slightly early
> Black-headed Grosbeaks and a Yellow Warbler, but true outliers have been no
> more numerous than a 'normal' spring based on the reports that I've seen.
>
> I'm sure that I appear more skeptical than most about out of season
> reports. This skepticism doesn't come from being a cranky, distrustful old
> guy who has nothing better to do with his time than cast doubt on the
> reports of other birders. My skepticism comes from 40+ years of seeing the
> same ID mistakes repeated year after year. I endorse the use of eBird and
> I think it is a wonderful tool. I have a similar opinion of OBOL, as it
> among the most lively and educational statewide birding forums in North
> America. Despite these endorsements, I do not accept (at face value)
> everything that I see reported through via these forums.
>
> If you think you are seeing a Swainson's Thrush in Oregon during April, I
> encourage you to take and post photos. It may seem silly to document a
> species that will be dirt common throughout much of Oregon a month from
> now, but if we are to stretch the bounds of current knowledge, rigor,
> objectivity, and proof need to be part of the process.
>
> Dave Irons
> Portland, OR
>
>
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