Date: 6/30/25 9:43 am From: David P. Muth via groups.io <muthdp...> Subject: Re: [labird] Golden-cheeked Warblers overfly LA
Eric--
Thanks for the tutorial and the clarifications. The bottom line is that the
specimen and photos from the Tampa area prove that it does occasionally
happen, and there seems to be a real possibility that it happens more often
than I suppose any of us imagined.
Peter brought up this paper in a discussion about Bachman's Warbler. I used
to argue (30 or 40 years ago) that Bachman's could easily be holding out in
some undiscovered remote location in the very under-birded and
under-studied mid-south. Others argued that it would still be detected
somewhere in migration in Florida or on the Gulf coast. I used to resist
that argument, pointing out that much of the Gulf coast was also poorly
covered. As more and more birders armed with better and better resources,
including now digital cameras, surveyed more and more of the coast, year
after year, my optimism faded to a very low point. But if Golden-cheeked
Warblers can be slipping past us regularly (and that remains to be
verified, as you point out), then I'd revise my hope back upward, if only
slightly. I don't think sedentary, large, loud and conspicuous, easily
identified Ivory-billed Woodpeckers could possibly still be holding out,
but small, early migrant, obscurely-plumaged (except adult males), warblers
might just.
David Muth
New Orleans
On Sun, Jun 29, 2025 at 8:48 AM Johnson, Erik via groups.io <Erik.Johnson=
<audubon.org...> wrote:
> Hi Peter and LAbird,
>
> Thanks for sharing this. Very interesting. Having worked with light-level
> geolocator data, I can appreciate some of the uncertainties it generates,
> especially during migration. Latitude is notoriously harder to estimate
> with accuracy than longitude, and the difference between Louisiana and
> southern Mexico can be hard to distinguish with certainty, especially as
> the date approaches the equinox. To illustrate this point, I'm happy to
> share location data generated from light from a geolocator we recovered
> this spring from Amite River Wildlife Sanctuary. You should be able to
> click through the dates to see how locations and the precision changes
> depending on stopover duration and proximity to the equinox.
> https://rpubs.com/Erik_I_Johnson/1301031 >
> Back the Golden-cheeked Warbler paper. The figure with the 11 movement
> trajectories showing easterly fall migrations does not show the
> uncertainty, so it's hard to be sure how realistic these lines are. But
> interestingly, the date of the fall migrations reported in the paper
> spanned July 1 to September 3, which is a good bit before the equinox, and
> there are apparently some longer stopover durations (which helps improve
> accuracy), so it is a little harder to poke holes in the idea of an
> easterly movement in fall.
>
> Such a "loop migration" pattern is exhibited by a number of Neotropical
> migrants, although many of those tend to be more boreal. There are even two
> recent documented records in eBird from late August in the Tampa, FL area
> (and also a specimen from late August in 1964), and early to mid-August
> Houston/Galveston-area records, suggesting the geolocator data showing the
> occasional trans-Gulf migration may have some validity. But I'd be
> surprised if it were as common as the paper suggests, given the paucity of
> records from the northern Gulf.
>
> Golden-cheeked Warbler populations continue to decline, unlike the rapidly
> increasing Black-capped Vireo, which now has records from LA. Even so,
> there's no reason to think Golden-cheeked Warbler wouldn't show up from
> time to time, and I think this geolocator study helps reinforce that. This
> species would (will) be an amazing (and overdue) first state record, but
> I'd be hesitant to use light-level geolocator data to accept it as a first.
>
> Erik Johnson
> Sunset, LA
> Erik.Johnson AT audubon.org
>
>
>
> -----Original Message-----
> From: <labird...> <labird...> On Behalf Of Peter H Yaukey via
> groups.io
> Sent: Sunday, June 29, 2025 7:35 AM
> To: LABIRD List <labird...>
> Subject: [labird] Golden-cheeked Warblers overfly LA
>
>
> LABirders:
> I read a (to me) shocking geolocator paper yesterday that reported that
> many Golden-cheeked Warblers travel far east from their nesting areas
> before turning south in fall, many apparently traversing Louisiana. The
> paper states that 20% of the birds in the study sample migrated across the
> Gulf in fall, including some going as far east as peninsular Florida. Here
> are the tracks of the c. 12 (of their total of 61 migrants tracked w
> geolocators) that went transgulf or through Florida.
>
> [cid:a9bc4c85-0d14-493e-947a-ed00063f054b]
> They had another map that gives stopover points. One of these is on the
> Chandeleurs. Has the LBRC considered whether a geolocator observation
> could constitute a first state record? The lead authors of the study are
> actually at LSU- perhaps they could provide information on the amount of
> precision in that stopover observation or the flyover tracks?
> This is crazy!
>
> [cid:2624d6e2-9708-4bd0-bcc2-9a578f417bf3]
>
> [cid:cac7bd43-7edd-4d8b-ab89-93ebac7375e8]
>
> NOTICE: This message, including all attachments transmitted with it, is
> intended solely for the use of the Addressee(s) and may contain information
> that is PRIVILEGED, CONFIDENTIAL, and/or EXEMPT FROM DISCLOSURE under
> applicable law. If you are not the intended recipient, you are hereby
> notified that any disclosure, copying, distribution, or use of the
> information contained herein is STRICTLY PROHIBITED. If you received this
> communication in error, please destroy all copies of the message, whether
> in electronic or hard copy format, as well as attachments and immediately
> contact the sender by replying to this email or contact the sender at the
> telephone numbers listed above. Thank you!
>
>
>
>
>
>
>
>
>
>
>
