Thursday, March 03, 2011

Three Small Falcons, and Thoughts on Speciation...

Anne Price of the Raptor Education Foundation flies the excellent taiga merlin Tish, who has been drawn by Vadim Gorbatov "bulldogging" a starling (Cowgirl Tish).

We were discussing Cheetah who is half taita (or teita) falcon. The species lives in the river gorges of eastern and southern Africa-- I have seen nests near Victoria Falls. Though small it is very stout, broad- shouldered, short- tailed, large- beaked, long- toed, and heavily wing- loaded. It has rusty marks on its head. In fact but for that it is somewhat isolated, and lives near dry forest rather than desert, it could be considered the smallest member of the Barbary falcon (Falco babylonicus) group, the desert "peregrine"-- the two subspecies, eastern and western, were once considered races of the peregrine until they were found breeding sympatricly with other races. This species is found from Morocco to western Mongolia, where I have seen THEIR nest sites, the western birds known as Barbary falcons and the eastern as red- naped shahins. The Barbs are little; some rn's are bigger than peregrines.

Look at the directions evolution has taken small falcons. The teita (a male, very small, about which more in a minute) is a tiny peregrine but stouter; the American aplomado has gone in a direction resembling an Accipiter with a falcon head, long, lanky, long tailed; the merlin is a mini- desert falcon built for swift pursuit.

Second pic: teita, unhappy Tish. Both weigh plus or minus 180 g; "little" Cheetah over 500.

Third: Anne with same. LOOK at proportions!

Fourth, fifth: Red Nape in Almaty Kz breeding project where she dwarfs a male Siberian peregrine-- yes, females are bigger but she was huge, though still with those broad shahin shoulders like a teita or Barb. Incidentally they are called Lashyn-- my dog's name-- there.

Last, male (I think) rn in Kyrgizstan.

Are the peregrine relatives, probably separated only 12,000 years or so, species or not? Check this scholarly pdf and get back to me...


dr. hypercube said...

Looking at the third picture (taita, Tish and Anne), all I could think of was that those little Zambezi bombers are the Chimney Swifts of the Falconidae.

therese said...

My thoughts on subspecies are pretty well known at least in the falconry web forum circles, but I never can pass up an chance to reiterate them :). Subspecies don't exist. Back in the day there were semivalid reasons to describe them (i.e. when systematics was still centered on the biological species concept). But we've moved far, far beyond that. Currently, we work with 20 or so different species concepts many of which have no problem with some gene flow between valid species. All that is required for me to recognize a species is it has to be diagnosably different (basically I have to know it is x species if you show me a specimen and/or give me a sequence of an appropriate gene or genes) and following its own evolutionary path. The fact it can hybridize with other related species isn't a big deal if it only happens in certain areas or under certain conditions. Add in the fact that the subspecific rank has been grossly misapplied, particularly in the bird world (some papers place it at 97% of subspecies being non-monophyletic), there is really no reason to continue recognizing them. It’s a slow process, but as the old guys die off and those of us trained in a truly phylogenetic framework take over, it's happening. We're also realizing species are more or less human constructs so I guess the fact we don't agree on what constitutes one or not shouldn't be a surprise.
I also have some issues with Mallet (2007) in general and his views on subspecies/species in conservation in particular. Since I'm most familiar with endangered species legislation in the US I'll use an example from it, but CITES takes a similar approach. There is no reason a subspecies can't be listed. ESA will list anything that is a distinct population segment. Doesn’t matter if it’s a species, a subspecies, or even a geographically isolated but nomenclaturally undifferentiated group. An example is the bald eagle, which was delisted except for a small portion of the population in Arizona ( if you're curious: Sonoran Desert DPS: Arizona: (1) Yavapai, northern Mexico. Gila, Graham, Pinal, and Maricopa, Counties; and (2) Southern Mohave County (that portion south and east of the center of Interstate Highway 40 and east of Arizona Highway 95), eastern LaPaz County (that portion east of the centerline of U.S. and Arizona Highways 95), and north of the centerline of Interstate Highway 8).) which is listed as threatened. Because of this I have a hard time buying his argument that subspecies are being neglected in conservation and resulting in elevating things to species status which don't warrant this rank. The validity of this approach is up for debate, but that's a whole different topic…
As far as the birds in question, Barbary's seem to be a pretty solid peregrine (using the current concept of peregrine). Genetically they aren’t particularly divergent and morphologically I'm not aware of any character or suite of characters which set them apart in all cases (that said I haven't been following the Barbary/ pere debate the last couple of years, so maybe some characters have emerged which separate them from the rest of what is currently considered peregrines ). Straight up sympatry is handy, but not a character to base species off of in my opinion. Red naped shaheens also appear to belong inside peregrines. If you want to raise these two groups to species status the same should be done with a number of other peregrine groups. The other 2 don't appear to be closely related to peregrines at all but rather appear to be most closely related to hobbys (although based on cytochrome b aplos are in a clade with American kestrels, I'm hesitant to accept something based on a single gene since I can easily pick a gene that tells me what I want to hear…).

Steve Bodio said...

Thanks for an excellent analysis!

I do wonder about teitas being close to hobbys--- they are much more like peregrines-- but I don't trust my intuition any more than you do single gene factors.

Any recommendation on books about species concepts? I have a couple on my Wish List:The Species Problem by Stamos and Species Concepts and Phylogenetic Theory by Wheeler.

therese said...

Hm, I can't think of any off hand. The Wheeler book is good, I've read parts of it although not from cover to cover (I should do that before my prelims...). There are also some good papers, the authors currently excape me, if I can find them I'll send them your way.

jnbszabo said...

Hi therese - stephen, happy to "overhear" your conversation - and i totally agree! with both of you.

Widening the perspective a bit you'll see what i mean - "species" are nothing but discretizations of a continuous phenonmenon - the ability of life to pop up in arbitrary sizes. 3 Accipiterters in temperate NA but only two in Europe implies a slightly narrower resource fauna.
The reason most faunas have only one peregrine is because they're to narrow to accommodate two.
And as far as the genetics ok, that's like ripping a phone apart to see if its apple or android, i mean great, but that's a different question, morphology and behavior follow the dictates of the environment, genetics is just the software that delivers the physically required characteristics.

Now where i agree with you, stephen, is that the three archetypes you mention peregrine, merlin/gyr and aplomado (which includes "all other" -kestrels, hobbies, luggers, etc.) Some "fence sitters" like sakers, are obviusly leaning towad gyrs,redhead merlins to merlins, lanners to praries, etc.

But I think the main root is peregrines - they are the most "unspecialized" raptor - they ride the peak of the entire avian fauna in evry biome that they appear and the only places on earth where they appear in two sizes is at the most dense avian resource centers on earth - the tropics. In the new world we have the ob-bf complex - the most clearly defined big/small peregrine on earth (and clearly o'm not talking about ob/bf being close or far from peregrine dna - in fact i could care less) because they are the functional peregrine of the american tropics. The Asian tropics have the F. p. peregrinator /F. severus (the so called "Oriental Hobby" - a bird so strikingly similar in size and coloration to the bf that when i saw the first good photos i had to rub my eyes.)

In Africa, if taitas are nesting close to F. p. minor (or whatever) we have another bird-fauna-broadness peak and find two peregrines.

In Australia macropus and longipennis may be another example.

Splitting from peregrines to gyrs/merlin/nz falcon in one direction, lanner, luggar, prarie, saker,... is an even further spread into territories covered by other "functionals" kites, harriers, buteos, accipiters etc. Those edge categories diversify quickly...

These are the bio-foundries that falcons and all species were formed in - and all resemblance to real characters is strictly accidental...