Discovered: a second breeding season for five migratory songbirds

[Chuck Hagner]

Hi everyone--

Biologists studying songbirds that breed in North America and then migrate to Mexico have discovered something totally unheard of in the New World -- a second breeding season.

Five species -- Yellow-billed Cuckoo, Orchard Oriole, Hooded Oriole, Yellow-breasted Chat, and Cassin's Vireo -- breed primarily in the United States and Canada. Then they squeeze in a second breeding season during a stopover in western Mexico on their southward migration.

A paper describing the discovery has been published in the online edition of the Proceedings of the National Academy of Sciences. Only the abstract is available to nonmembers, but Associate Editor Matt Mendenhall has written a detailed summary for our blog:

Researchers discover a second breeding season for five migratory songbirds
Birder's World Field of View
http://is.gd/4CUFH


Chuck Hagner
Editor, Birder's World Magazine
Twitter: @CH_BirdersWorld
www.BirdersWorld.com

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[Brandon Best]

Chuck and all,

Fascinating indeed, but not completely unheard of in the New World, I
think.  Phainopeplas breed in the deserts and then also in arid woodlands.
From Cornell's All About Birds website (www.allaboutbirds.com):

"The Phainopepla exhibits strikingly different behaviors in its two
habitats. In the desert, it is territorial, actively defending nesting and
foraging sites, while in the woodlands it is colonial, with as many as four
nesting pairs sharing one large tree."

I think Cassin's Vireos are most interesting here, given their close
relationships with Plumbeous and Blue-headed Vireos, which do not (?) hold a
second breeding season.  Then again, Yellow-billed Cuckoos are pretty
intruiging as well.  Some portions of their population migrate south via the
islands of the West Indies and do not stop over and breed (or perhaps they
do?).  Fun stuff.

Brandon Best
Lawrenceville, GA

On Mon, Oct 26, 2009 at 3:12 PM, Chuck Hagner <chagner@...> wrote:

> Hi everyone--
>
> Biologists studying songbirds that breed in North America and then migrate
> to Mexico have discovered something totally unheard of in the New World -- a
> second breeding season.
>
> Five species -- Yellow-billed Cuckoo, Orchard Oriole, Hooded Oriole,
> Yellow-breasted Chat, and Cassin's Vireo -- breed primarily in the United
> States and Canada. Then they squeeze in a second breeding season during a
> stopover in western Mexico on their southward migration.
>
> A paper describing the discovery has been published in the online edition
> of the Proceedings of the National Academy of Sciences. Only the abstract is
> available to nonmembers, but Associate Editor Matt Mendenhall has written a
> detailed summary for our blog:
>
> Researchers discover a second breeding season for five migratory songbirds
> Birder's World Field of View
> http://is.gd/4CUFH
>
>
> Chuck Hagner
> Editor, Birder's World Magazine
> Twitter: @CH_BirdersWorld
> www.BirdersWorld.com
>
> BirdChat Guidelines: http://www.ksu.edu/audubon/chatguidelines.html
> Archives: http://listserv.arizona.edu/archives/birdchat.html
>

BirdChat Guidelines: http://www.ksu.edu/audubon/chatguidelines.html
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[Jerry Friedman]

The study seems fascinating!  I'm having trouble figuring out
what's going on from that summary, so I wish the PNAS made
articles available instead of just abstracts.

As I understand the article, only the two orioles were
observed to breed.  In the others, the males were engaging
in breeding behavior such as guarding females and singing.
There's no proof that any of the birds bred in both the
north and Mexico, and the abstract of the PNAS article
makes no such claim.  This seems to put the orioles in the
same category as the Phainopepla, as Brandon Best mentioned.
According to the BNA on line, the Phainopepla is known to
breed in the desert in spring and in wooded canyons in summer,
but the migration routes haven't been traced and no one
knows whether the same birds breed in both places.

Some females (did these include the ones that laid eggs?)
had featherless but non-vascularized brood patches,
indicating that they had bred that season.  This is where
my ornithological knowledge falls short.  Wouldn't that
mean that they /weren't/ breeding, since then their
brood patches would be vascularized?  No doubt I'm
missing something (maybe as simple as the high
temperatures meaning that not much is necessary to keep
eggs warm).

Stable-isotope analysis showed that many of the birds
had just come from farther north.  Did these include the
nesting pairs of the two oriole species?  Did they
include the males that were showing breeding behavior?

A point that seems definite is that these migrants
didn't include any recently fledged birds.  Thus the
recent breeders probably have left their young, which
have to find their wintering grounds in Central America
without their parents.  Of course, going south from
the western U.S. and avoiding sea crossings, you can
hardly miss Central America, but maybe there's a
puzzle about how the fledgelings find the right habitat.

If the question is whether any birds breed in the U.S.
or Canada and again in Mexico, I'd think radio tracking
could answer it--if it's technically and financially
feasible.  Is that right?  Are there other ways (beside
banding birds known to have bred and hoping to find
them again)?

Jerry Friedman

--- On Mon, 10/26/09, Chuck Hagner <chagner@...> wrote:

> From: Chuck Hagner <chagner@...>
> Subject: [BIRDCHAT] Discovered: a second breeding season for five migratory songbirds
> To: BIRDCHAT@...
> Date: Monday, October 26, 2009, 1:12 PM
> Hi everyone--
>
> Biologists studying songbirds that breed in North America
> and then migrate to Mexico have discovered something totally
> unheard of in the New World -- a second breeding season.
>
> Five species -- Yellow-billed Cuckoo, Orchard Oriole,
> Hooded Oriole, Yellow-breasted Chat, and Cassin's Vireo --
> breed primarily in the United States and Canada. Then they
> squeeze in a second breeding season during a stopover in
> western Mexico on their southward migration.
>
> A paper describing the discovery has been published in the
> online edition of the Proceedings of the National Academy of
> Sciences. Only the abstract is available to nonmembers, but
> Associate Editor Matt Mendenhall has written a detailed
> summary for our blog:
>
> Researchers discover a second breeding season for five
> migratory songbirds
> Birder's World Field of View
> http://is.gd/4CUFH
>
>
> Chuck Hagner
> Editor, Birder's World Magazine
> Twitter: @CH_BirdersWorld
> www.BirdersWorld.com
>
> BirdChat Guidelines: http://www.ksu.edu/audubon/chatguidelines.html
> Archives: http://listserv.arizona.edu/archives/birdchat.html
>

     

BirdChat Guidelines: http://www.ksu.edu/audubon/chatguidelines.html
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[Jules Levin]

>At 09:52 PM 10/26/2009, you wrote:
>>The study seems fascinating!  I'm having trouble figuring out
>>what's going on from that summary, so I wish the PNAS made
>>articles available instead of just abstracts.

In this regard, maybe someone could explain to me why, every late
morning to afternoon, I hear from a street-facing
bedroom window a mockingbird going through his whole repertoire of
riffs with great enthusiasm.  This is Los Angeles,
and if the research paper I read about 30 years ago at UC Riverside
is still valid, we in Southern California have a winter population
of mockingbirds who breed in the great Northwest (B.C., etc.), while
our summer breeders are wintering in the warmth of Central
America or thereabouts.   I am pretty sure the migration has already
taken place.
  I have heard (and seen) infrequently in the winter a mockingbird
practicing some quiet tune on a lower branch, which I assumed
  was a first-year teenager beginning to feel his oats, but the bird
I hear now really sounds like he means business!
Jules Levin
Los Angeles
Desert Hot Springs  

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[Rick-124]

Is it available on SORA ?


Jerry Friedman wrote:

> The study seems fascinating!  I'm having trouble figuring out
> what's going on from that summary, so I wish the PNAS made
> articles available instead of just abstracts.
>
> As I understand the article, only the two orioles were
> observed to breed.  In the others, the males were engaging
> in breeding behavior such as guarding females and singing.
> There's no proof that any of the birds bred in both the
> north and Mexico, and the abstract of the PNAS article
> makes no such claim.  This seems to put the orioles in the
> same category as the Phainopepla, as Brandon Best mentioned.
> According to the BNA on line, the Phainopepla is known to
> breed in the desert in spring and in wooded canyons in summer,
> but the migration routes haven't been traced and no one
> knows whether the same birds breed in both places.
>
> Some females (did these include the ones that laid eggs?)
> had featherless but non-vascularized brood patches,
> indicating that they had bred that season.  This is where
> my ornithological knowledge falls short.  Wouldn't that
> mean that they /weren't/ breeding, since then their
> brood patches would be vascularized?  No doubt I'm
> missing something (maybe as simple as the high
> temperatures meaning that not much is necessary to keep
> eggs warm).
>
> Stable-isotope analysis showed that many of the birds
> had just come from farther north.  Did these include the
> nesting pairs of the two oriole species?  Did they
> include the males that were showing breeding behavior?
>
> A point that seems definite is that these migrants
> didn't include any recently fledged birds.  Thus the
> recent breeders probably have left their young, which
> have to find their wintering grounds in Central America
> without their parents.  Of course, going south from
> the western U.S. and avoiding sea crossings, you can
> hardly miss Central America, but maybe there's a
> puzzle about how the fledgelings find the right habitat.
>
> If the question is whether any birds breed in the U.S.
> or Canada and again in Mexico, I'd think radio tracking
> could answer it--if it's technically and financially
> feasible.  Is that right?  Are there other ways (beside
> banding birds known to have bred and hoping to find
> them again)?
>
> Jerry Friedman
>
> --- On Mon, 10/26/09, Chuck Hagner <chagner@...> wrote:
>
>  
>> From: Chuck Hagner <chagner@...>
>> Subject: [BIRDCHAT] Discovered: a second breeding season for five migratory songbirds
>> To: BIRDCHAT@...
>> Date: Monday, October 26, 2009, 1:12 PM
>> Hi everyone--
>>
>> Biologists studying songbirds that breed in North America
>> and then migrate to Mexico have discovered something totally
>> unheard of in the New World -- a second breeding season.
>>
>> Five species -- Yellow-billed Cuckoo, Orchard Oriole,
>> Hooded Oriole, Yellow-breasted Chat, and Cassin's Vireo --
>> breed primarily in the United States and Canada. Then they
>> squeeze in a second breeding season during a stopover in
>> western Mexico on their southward migration.
>>
>> A paper describing the discovery has been published in the
>> online edition of the Proceedings of the National Academy of
>> Sciences. Only the abstract is available to nonmembers, but
>> Associate Editor Matt Mendenhall has written a detailed
>> summary for our blog:
>>
>> Researchers discover a second breeding season for five
>> migratory songbirds
>> Birder's World Field of View
>> http://is.gd/4CUFH
>>
>>
>> Chuck Hagner
>> Editor, Birder's World Magazine
>> Twitter: @CH_BirdersWorld
>> www.BirdersWorld.com
>>
>> BirdChat Guidelines: http://www.ksu.edu/audubon/chatguidelines.html
>> Archives: http://listserv.arizona.edu/archives/birdchat.html
>>
>>    
>
>
>      
>
> BirdChat Guidelines: http://www.ksu.edu/audubon/chatguidelines.html
> Archives: http://listserv.arizona.edu/archives/birdchat.html
>
>  

--

Rick
Fargo, ND
N 46°53'251"
W 096°48'279"


Remember the USS Liberty
http://www.ussliberty.org/







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[Brad Bolduan]

Although not proven.  Similiar behavior has certainly been previously
suspected in other North american Species (i.e. Sedge Wren and Phainopepla).
I see someone else mentioned Phainopepla as well.  A article discussing the
Sedge Wren case is on SORA at
http://elibrary.unm.edu/sora/Wilson/v108n01/p0115-p0122.pdf

Brad Bolduan
Windom, MN


>> From: Chuck Hagner <chagner@...>
>> Subject: [BIRDCHAT] Discovered: a second breeding season for five
migratory songbirds

>> To: BIRDCHAT@...
>> Date: Monday, October 26, 2009, 1:12 PM
>> Hi everyone--
>>
>> Biologists studying songbirds that breed in North America
>> and then migrate to Mexico have discovered something totally
>> unheard of in the New World -- a second breeding season.
>>
>> Five species -- Yellow-billed Cuckoo, Orchard Oriole,
>> Hooded Oriole, Yellow-breasted Chat, and Cassin's Vireo --
>> breed primarily in the United States and Canada. Then they
>> squeeze in a second breeding season during a stopover in
>> western Mexico on their southward migration.
>>
>> A paper describing the discovery has been published in the
>> online edition of the Proceedings of the National Academy of
>> Sciences. Only the abstract is available to nonmembers, but
>> Associate Editor Matt Mendenhall has written a detailed
>> summary for our blog:
>>
>> Researchers discover a second breeding season for five
>> migratory songbirds
>> Birder's World Field of View
>> http://is.gd/4CUFH
>>
>>
>> Chuck Hagner
>> Editor, Birder's World Magazine
>> Twitter: @CH_BirdersWorld
>> www.BirdersWorld.com

BirdChat Guidelines: http://www.ksu.edu/audubon/chatguidelines.html
Archives: http://listserv.arizona.edu/archives/birdchat.html

BirdChat Guidelines: http://www.ksu.edu/audubon/chatguidelines.html
Archives: http://listserv.arizona.edu/archives/birdchat.html