Date: 10/7/19 9:42 pm
From: Robert O'Brien <baro...>
Subject: [obol] Re: Oregon eBird Tropical Kingbird statistics
Joel & OBOL

Some years ago I said on OBOL that there is more to birding than
identifying individual birds.
Well, there is also more to birding than eBird, as several OBOLers have
lately mentioned.
But, in this case, both are involved, which makes it either doubly
interesting or doubly dull.
And I imagine that those in the latter camp aren't even reading this email.
There could be 100's of non-readers. 1000's?

I agree with Joel's statement that calling all kingbirds Tropical is
unlikely to have a large effect on the Tropical distribution maps
Even though there are only 10 calling eBird records from Oregon up through
2016 (see below). Especially since there are also records from Washington
and British Columbia; but which I have not analysed.

I do concede to Joel that you only need to identify an individual bird
once. Then it stays identified so long as it stays put.

So I've gone back to the eBird data to see how many of the non-calling
reports were of a bird that was identified by
at least one person hearing the call. There a significant number of such
cases, as Joel intimidated, but the last one in the table below wins hands
down.
There were 55 reports of this bird and only 1 person reported it
calling. Twenty eight eBirders reported that kingbird on 11/20/2016
(Lincoln City) and three reported it at from the exact time as the single
mention of calling. Clearly a close call. One would have to guess that
more than one person heard the call, but didn't think to mention it. Ergo
my previous suggestion that with this species one should* always* mention
vocalization: *yes or no*. And most especially if you hear Kip,
kip.....................

As the table below shows, there were 101 reports of Tropicals of which
only a single person reported the call. There were two reports of a bird
that 2 out of 5 observers independently reported calls two days apart.

Now with the data as reported (and neglecting possible failure to report
heard calls) you can subtract 101 from 302, leaving 201 allegedly 'silent'
reports, 2/3 of the total reports, which were technically-unsubstantiated
reports of the 'Oregon' expectation. Any of these could have been a
silent Couch's or even a calling Couch's that the observer failed to report
on. A calling Couch's has a very high probability of NOT being reported as
it is just assumed to be a Tropicall, except by an alert, experienced
birder. There are 201 Kingbird reports that fall into this category in
Oregon. I have to agree with the original OBOL recommendation that such
observations should appear as Tropical/Couch's, a classification available
in eBird. Otherwise what is the point of this classification. If you wish
to confirm the species, get there early, sit there all day if necessary,
hoping for a call. Then report that you observed the bird for 10 hours and
it was silent the entire time! As Tropical/Couch's.

Bob OBrien Carver OR See updated table below. Individual
reports are total reports of that bird at that locations and time period..
Days gives the period over which the bird was observed at the same
location, not necessarily every day. This assumes that it wasn't a Cassin's
or a Western Kingbird, unlikely at this location and time of year, but so
is a Couch's.

OBSERVATION DATE Calling Vocalizing Individual Reports Days Report
Calls SPECIES
COMMENTS Observations from earliest
reports through 2016
11/06/12 Yes 5 5 2 One in 8' pine about 15 ft from me along fenceline, the
other at top of a spruce. Both had bright yellow belly and breast, white
throat. Calling between both birds, single note brief trill. Both actively
feeding. These birds have been reported by others at this location during
the last few days.
11/08/12 Yes same same same Reported on OBOL. Hawking insects from low to
middle height perches. Deeply notched dark--brown tail, no white edging.
Calls as in Sibley app.
11/01/13 Yes 1 1 1 Photos available upon request (both myself and Tom got
some). This is presumably the same bird that many have been seeing at this
location. Vocalizing freely with characteristic metallic twitter. Obvious
kingbird morphology and behavior, sitting on various treetop perches and
flycatching before returning to perch. Forked tail and long heavy bill and
yellow breast evident.
11/27/13 Yes 1 1 1 1st thought WEKI, but this bird had a forked tail,
yellow up the chest to throat, much yellow underside of wings, no white
tail margins, also it vocalized as we were leaving.. in true TK form..
woohoo
11/05/14 Yes 1 1 1 Found today by Janet Lamberson, who told me of it. Thank
you, Janet! About 2 minutes after I stepped out of the car, I heard the
characteristic chittering call of this species. As I jogged toward the
sound, I saw two birds in the air and realized it was the kingbird being
chased by a Sharp-shinned Hawk! The Sharp-shin came within a couple of feet
and just missed. The kingbird escaped and flew about 200 m to a perch atop
a tall conifer and continued chittering. Apparently it was really worked up
(understandably so!) -- and likely had been scolding the hawk in the first
place when I'd initially heard it.
12/13/14 Yes 13 8 1 Seen by others previously at this location recently.
Watched it fly from the east into the trees behind the pizza shop calling.
10/02/15 Yes 4 4 1 Yellow-bellied Kingbird, much larger bill than western.
Rattling call different than western. Photo.
11/03/15 Yes 5 11 1 Heard his trilling call across the pond near the
parking lot first- I was on the northern side opposite. Used my scope to
locate him on roadside wires. Distant view but could detect his yellow
breast, large bill and characteristic kingbird perching style. Wasn't able
to relocate when I returned to parking lot. Seen here previously a couple
weeks ago.
11/29/15 Yes 16 14 1 Photos plus heard calling giving the zippy trill which
we are very familiar with. Video can be seen at:
https://youtu.be/GWvazZS_GZM.
11/20/16 Yes 55 13 1 Heard and seen. Twittery call diagnostic (as opposed
to the "pip" of a Couch's). Primaries appeared to be of uneven length which
also suggests Tropical rather than Couch's, which tend to have evenly
spaced primaries (Couch's).--Seen in shrubbery on the south side bank of
river downstream from bridge.

*TOTALS* *101* *58* *10*



On Fri, Oct 4, 2019 at 5:53 AM <clearwater...> wrote:

> P.S. To be a little more accurate, not all of those 17 reports on the
> Wireless Rd. bird from Nov-Dec 2015 were independent observations. Some
> were by people birding together who gave identical comments/photos in their
> reports. From a quick glance through, there were about 11 independent
> observations in the series, one of which (by Shawneen Finnegan and Dave
> Irons on 29 Nov 2015) includes a description of typical Tropical Kingbird
> vocalizations.
>
> If anyone has bottomless energy to dig into this, you might consider
> making a table like in the attached graphic, to summarize the evidence for
> each *series* of observations of a single or flock of reported Tropical
> Kingbirds at a given location. This is rather tedious, and some
> interpretation is needed to handle cases where people have posted
> checklists for personal/GPS locations rather than using an eBird "hotspot."
>
> But personally and probabilistically, I feel like I've looked at enough of
> these reports to establish that there is no reasonable cause to doubt that
> at least 90% of Tropical Kingbird reports in our region can safely be
> treated as such, for any reasonable use of these data in an aggregated
> analysis.
>
> --
> Joel Geier
> Greater Tampico, Benton County
>

 
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