Wish I had been there! Off topic, but I noticed that a few photos were uploaded to the wrong species. Jennifer Coulson Pearl River, LA On Wed, Apr 24, 2024 at 9:01?PM Johnson, Erik via groups.io <Erik.Johnson= [email protected]> wrote: LAbird,
I looked up cuckoo continental population estimates in the Partners in
Flight Database, which is largely based on USGS Breeding Bird Survey data.
About 8.4 million Yellow-billed Cuckoos in the U.S. and Canada versus about
0.9 million Black-billed Cuckoos, or a 10:1 ratio.
()
So why the 100:1 ratio detected in migration per Van (I'm inclined to
agree with that). Interesting that with a low sample, Robb got more of a
10:1 ratio in nocturnal flight - would be interesting to know how that
stacks up across a season, or multiple seasons.
In the eBird weekly abundance maps, Black-billed Cuckoo all but disappears
in migration.
My hunch is that Black-billed Cuckoo is more of a long-distance jumper
than Yellow-billed Cuckoo, which may be better described as a
short-distance skipper. The corollary is that Black-billed would pass
through faster, thus is less available for detection.
An alternative (or contributing factor) is that Black-bills are a lot less
easy to detect, but I just don't believe that Yellow-billed Cuckoo is 10x
as likely to be detected as a Black-billed. Black-bills do seem to be a lot
less vocal, however, so maybe that's some of it.
Someone needs to do a migration tracking study on Black-billed Cuckoos!
Only 3 Motus tags ever deployed, and no other tracking information seems to
be published.
Happy migration!
Erik Johnson
Sunset, LA
Erik.Johnson AT Audubon.org
-----Original Message-----
From: [email protected] <[email protected]> On Behalf Of Robb Brumfield via
groups.io
Sent: Wednesday, April 24, 2024 8:22 PM
To: James V Remsen <najames@...>; Jack Rogers <jack@...>
Cc: LABIRD <[email protected]>
Subject: Re: [labird] SEG Environmental Chandeleur Islands Trip 23 April
2024
From my nocturnal flight call station in Baton Rouge the evening of April
22nd was a season high for migrating cuckoos. Between 9:30 pm and 3:30 am
(April 23rd) I had 24 individual yellow-billed and 2 black-billed.
Robb
Robb T. Brumfield, PhD
Associate Dean of Research & Administration, College of Science Roy Paul
Daniels Professor of Biological Sciences Curator of Genetic Resources,
Museum of Natural Science Louisiana State University | lsu.edu |
science.lsu.edu/
office: 225-578-4206|mobile: 225-202-8892|fax: 225-578-8826 robb@...
<mailto:robb@...>
From: [email protected] <[email protected]> on behalf of James V Remsen via
groups.io <najames@...>
Date: Wednesday, April 24, 2024 at 7:49?PM
To: Jack Rogers <jack@...>
Cc: LABIRD <[email protected]>
Subject: Re: [labird] SEG Environmental Chandeleur Islands Trip 23 April
2024 Jack et al. ¡ª wow, what an experience! Fascinating.
As for the cuckoo prevalence ¡. Another hypothesis is that it was just one
of those ¡°cuckoo waves¡±. Spring waves are often dominated by one taxonomic
category. For example, sometimes there are ¡°cardinaline days" with
buntings, grosbeaks, and Dickcissels making up the bulk of the migrants.
Rarely there are ¡°thrush days, with Catharus species and Wood Thrush
predominating. Sometimes warblers steal the show. Sometimes Catbirds or
R-e Vireos are way over-represented.
As fo YB vs. BB cuckoos ¡ª indeed it¡¯s pretty clear that YB is a common
bird with a huge overall population, and BB is generally scarce. Although
YB has a larger breeding distribution, the difference is small compared to
the ratio of migrants detected, which I suspect is at least 100:1. Why the
disparity is so great is a mystery to me and to my buddies with whom I¡¯ve
discussed this on long birding trips. My personal high count for BB is 5,
way back in April 1979, and nowadays, seeing more than 1 in day is a big
deal. There have been years when I¡¯ve not seen one at all.
Van Remsen
===================
Dr. J. V. Remsen
Emeritus Prof. of Natural Science and Curator of Birds Museum of Natural
Science/Dept. Biological Sciences LSU, Baton Rouge, LA 70803
najames<at>LSU.edu
On Apr 24, 2024, at 5:01 PM, Jack Rogers via groups.io <jack= [email protected]> wrote:
[You don't often get email from jack@.... Learn why
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LaBird
I hope you all have been having a birdy spring! Hopefully we get one
more front before the end of the month--these south winds have been
killing me!
I wanted to write to talk about the crazy day on the Chandeleurs that
we had yesterday. As part of an ongoing survey by SEG Environmental,
we bird the island once a month looking to assess the numbers of
several target species (Red Knot, Chandeleur Gull, Wilson's/Piping/Snowy Plovers, etc.).
I think that we have all been most excited for the April survey, and
it definitely lived up to expectations.
For those that have not had the pleasure of visiting the Chandeleurs,
it is an amazing place. Most (I would estimate over 90%) of the
island's vegetation is Saltmarsh Cordgrass (Spartina alterniflora); in
some of the slightly higher elevation areas, there is also Phragmites
and Groundsel as well. Matt Conn and I surveyed the northern tip of
Chandeleur Island, which has almost no vegetation except for Spartina.
The birding was nothing short of excellent-we had 81 species (+1
Chandeleur Gull), which I think is pretty great considering there is
only 1 tree in that section (a 6 ft tall Mangrove). There were about
7 small mounds in the saltmarsh that had small groundsel bushes or
Phragmites stands. Each bush or stand of Phragmites was astoundingly
full of migrants. Take a look at our eBird checklist here
<<
70012706>> for the full rundown. My personal highlight was the best
Black-billed Cuckoo looks I can ask for! I know several other groups
had great birds as well: Cape May Warbler (x2), Yellow Rail (!!), and Blackpoll Warblers were seen by other surveyors on their more southerly
transects.
I was most interested by the incredible density of Cuckoos compared to
smaller migrants (e.g. warblers, buntings, etc). The only thing I can
think of is that there is really nothing for cuckoos to eat on the
islands:
there is no fruit, no insects much larger than saltmarsh moths or
horseflies, nothing that Cuckoos could theoretically refuel themselves
with after a trans-Gulf flight. Whereas there are plenty of tiny
insects (aphids, mosquitos, miniscule beetles and saltmarsh flies) for
warblers to eat, and plenty of seeds for INBUs etc. I also found the
ratio of Yellow- to Black-billed Cuckoos interesting. I believe that
Matt and I had a 100% detection rate of Cuckoos within our section,
and am pretty positive in a 100% correct identification rate as well.
I have always thought that my lack of mainland BB Cuckoos was a
detection error, but now I am wondering if it is more of a disparity in population sizes.
I wrote this in my eBird comments, but this was really one of the most
exciting days of birding in my life. Small groundsel bushes (2 feet
high with a diameter of 18 inches) were holding ridiculous totals of
birds such as one that held 7 Y-b Cuckoos, 3 Catbirds, 2 Ovenbirds, 1
Swainson's Thrush, and 2 Yellow Warblers. An absolutely incredible
experience, and just wanted to share that with you all.
Thanks for reading this monologue and good birding to y'all, Jack
Rogers
--
Jack Rogers
LSU Renewable Natural Resources
Baton Rouge, Louisiana/Mt Pleasant, SC My Flickr page
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Jennifer Outlaw Coulson