Great-tailed Grackles (1 Viewer)

[Daniel Philippe]

How many species in the mexicanus/major complex ?

In the sixties/seventies we were told that we had 2 species http://elibrary.unm.edu/sora/Auk/v105n03/p0516-p0528.pdf, and today most checklists reflect this.

Then we had this abstract of the 123rd Stated Meeting of the American Ornithologists' Union (23 - 27 August 2005) at the University of California Santa Barbara, CA:
302 Wehtje, Cacosta & Klicka
Phylogeography of two closely related and expanding species: the Great-tailed and Boat-tailed grackles.
WALTER WEHTJE, California State Univ., Northridge, CA, JEFFREY M. CACOSTA and JOHN KLICKA, Marjorie Barrick Mus., Las Vegas, NV.
The Great-tailed (Quiscalus mexicanus) and the Boat-tailed (Q. major) Grackles were considered 1 species as recently as 1957, but were split into distinct species based on differences in morphology, behavior and vocalizations. The larger Q. mexicanus generally prefers upland environments, while the smaller Q. major is found predominantly in marshes. The vocalizations and courting displays of males are noticeably different. During the past 100 yr both species have expanded their distributions in North America, with Quiscalus mexicanus expanding northward from Mexico into the central and w. U.S., and Q. major along the Atlantic coast and Gulf of Mexico into Texas and along the Atlantic coast as far as New York. This expansion has created a zone of overlap in their distributions in e. Texas and w. Louisiana, where hybrids have been documented. This study analyzes the relationship between these species using a sequenced mitochondrial DNA gene. Results show that Q. mexicanus is comprised of 2 well-defined clades, corresponding approximately with western (Q. m. nelsoni) and eastern (Q. m. monsoni and prosopidicola) subspecies, but these are not sister groups. Rather, the eastern clade of Q. mexicanus is sister to Q. major. Complicating matters, the boundary between the western and eastern forms of Q. mexicanus has been eroded by recent range expansion.

Today there is this short communication in The Condor Volume 110, Issue 1 February 2008:
http://cooper.org/COS/110_1/110_1abs21.pdf(I haven’t got the whole paper yet) confirming the above.

Do we know anything about Mexican ssp ? Do they fall in these groups ?

 

[Richard Klim]

Do we know anything about Mexican ssp ? Do they fall in these groups ?

Daniel,

from Alderfer, J. ed. 2006. National Geographic Complete Birds of North America:

"Historically the mountains of central Mexico divided the general population of Great-tailed Grackles into an eastern and central group and a western group. The "Western" Great-tailed Grackles - from nelsoni in the north, to coastal forms in west Mexico south to Guerrero - are small, they have a noticeably different song than the more eastern populations, and there are genetic differences."

This would give a western group comprising nelsoni, graysoni and obscurus; with the eastern/central group presumably containing the remaining subspecies (monsoni, prosopidicola, mexicanus, loweryi and peruvianus).

Richard

 

[l_raty]

Do we know anything about Mexican ssp ? Do they fall in these groups ?

I don't have the Condor paper either (not even sure it is actually published), but their ND2 sequences are in GenBank, with geographical annotations, so it's not too difficult to find out what they show.
The western clade is present in samples from Sonora and California; both clades are present in Arizona and Nevada; the other birds they sampled were from New Mexico, Oklahoma and Texas in the US, Tamaulipas, Mexico City and Oaxaca in Mexico, Guatemala, Nicaragua, Honduras, and Panama - all of these fall in the eastern clade (sister to Q. major).
These data place only nelsoni with certainty in the western group, and monsoni, prosopidicola, mexicanus, and peruvianus in the eastern group.
On simple geographical grounds, it would be very surprising if loweryi didn't fall in the eastern group too.
This leaves graysoni and obscurus unclassified, but see Richard's message.

Laurent -

 

[Daniel Philippe]

Thank you Richard,

But if the split is like this, size may not be the safest criteria to tell them apart. Jaramillo & Burke (1999) give measurements for all ssp and if the smallest are clearly graysoni & nelsoni, obscurus is noticeably bigger, bigger than peruvianus for instance. They also say that loweryi “is much smaller than adjacent mexicanus, enough to be noticeable in the field.”

… and thank you Laurent for digging out the relevant info from the NCBI labyrinth and converting it into readable English.

Now if we include Q. major in the tree, it should be interesting to see where torreyi (the migratory taxon with yellow eyes) shows up.

Daniel

 

[Richard Klim]

But if the split is like this, size may not be the safest criteria to tell them apart.

Although Alderfer also mentions song and 'genetic differences', no specific details are provided.

Of interest is that the females of nelsoni and graysoni are pale, whereas those of obscurus are dark; and Jaramillo & Burke comment that the songs of graysoni and obscurus are apparently structurally different.

So perhaps the 'western' clade extends south only to Sinaloa (including just nelsoni and graysoni), rather than to Guerrero (as suggested by Alderfer)?

P.S. Although BNA provides subspecies descriptions, it does not discuss the existence of any 'groups'.

Richard

 

[Gentoo]

To add to the confusion, the California population appears to be from two different clades:

http://montereybay.com/creagrus/grackles.html

 

[Alexis Powell]

So perhaps the 'western' clade extends south only to Sinaloa (including just nelsoni and graysoni), rather than to Guerrero (as suggested by Alderfer)?

I don't usually make it out of the optics forums here on Birdforum, but I just happened upon this thread while doing a google search for something else. You may be interested to know that I (in collaboration with Keith Barker and Scott Lanyon) recently completed a species-level phylogeny of grackles based on mtDNA that includes some intraspecific sampling of mexicanus, lugubris, and niger, and includes two species not included in other phylogenies--palustris (extinct), and nicaraguensis. Not sure how much to say here--the paper is done but has only just been submitted. There are a few modest surprises/interesting results relevant to this discussion, including that obscurus is in the eastern mexicanus clade and that palustris is the well differentiated sister lineage to the western clade.

--AP

 

[Richard Klim]

...a few modest surprises/interesting results relevant to this discussion, including that obscurus is in the eastern mexicanus clade...

--AP

Alexis,

Many thanks for that insight. Looking forward to reading your paper.

Richard

 

[Daniel Philippe]

Looking forward to reading your paper.

Great article Alexis.

In case you haven't read it yet Richard, here it is: http://www.tc.umn.edu/~barke042/Publications.php

The second one.

 

[Richard Klim]

Great article Alexis.

In case you haven't read it yet Richard, here it is.

Yes, Alexis. You've certainly addressed the issues raised in this thread.

Many thanks Daniel. :t:

Richard

 

[Nutcracker]

From the original post:

In the sixties/seventies we were told that we had 2 species http://elibrary.unm.edu/sora/Auk/v105n03/p0516-p0528.pdf, and today most checklists reflect this.

Dead link, but available archived here.