sandee@sun13.scri.fsu.edu (Daan Sandee) (06/26/90)
In article <306@spam.ua.oz> wvenable@spam.ua.oz (Bill Venables) writes: >First a word of explanation. For some reason this news group now >comes to Australia. I'm not sure if North American readers will be >all that interested in notes on Australian birds, but I guess they >will let me know in the customary way! Sure we're interested for any news from the (both ornithologically and other- wise) fascinating Fifth Continent. [ story about wedgebills being distinguishable by voice only ] >More recently the two have been re-classified and are now regarded as >conspecific, although such are the vagaries of academic pigeon-holing >I can't say for how long. :-) >Regards, Bill Venables. Interesting. The A.O.U. (that's American, not Australian) treats two populations as distinct species if they, under normal circumstances, do not significantly interbreed. Whether they are sympatric or allopatric is not really an issue, although it makes the determination of the degree of interbreeding much easier if they are allopatric. From your description, it sounds as if the wedgebills should be regarded as two species. In the U.S., the only recent case of a voice-based split is the Traill's Flycatcher, which was split into Alder and Willow Flycatcher. The two species have a largely similar distribution, but within that area prefer different habitats. They can (apart from choice of habitat) be distinguished by song only - well, sort of ; actually, the songs aren't all that different. I can think of no example in American ornithology where two species that were distinguishable by voice only, have been lumped. Daan Sandee sandee@sun16.scri.fsu.edu Supercomputer Computations Research Institute Florida State University, Tallahassee, FL 32306-4052 (904) 644-7045
wvenable@spam.ua.oz (Bill Venables) (06/27/90)
In article <151@sun13.scri.fsu.edu> sandee@sun13.scri.fsu.edu (Daan Sandee) writes: > >Interesting. The A.O.U. (that's American, not Australian) treats two >populations as distinct species if they, under normal circumstances, >do not significantly interbreed. If you add "in the wild", that was my understanding of the official RAOU position also. However this is clearly not the full story. There are many examples in Australia of sedentary birds which have a range consisting of several discrete areas, sometimes hundreds of kilometers apart, between which migration, and hence interbreeding, does not occur, and yet they are still regarded as a single species. To name just two, the crimson rosella (a parrot) and the satin bower bird. Official lists still have the wedgebills as two species, Psophodes cristatus and P. occidentalis, although it has been suggested in the local literature that they should be not so regarded. I do not have the references to hand so I can't say on what basis this suggestion has been made, but the ranges are both so remote that I suspect that study "in the wild" can't be easy. (My suggestion that they "had recently" been re-classified was premature. Sorry!) The determination of sepcies status is a strangely contentious issue in Australia, and some rather iconoclastic revisions have recently been suggested which are generating a good deal of heated debate. Is this an antipodean peculiarity or is it the case everywhere?-- Bill Venables, Dept. Statistics, | Email: wvenable@spam.ua.oz.au Univ. of Adelaide, South Australia. | Phone: +61 8 228 5412
dmark@acsu.Buffalo.EDU (David Mark) (06/27/90)
In article <151@sun13.scri.fsu.edu> sandee@sun13.scri.fsu.edu (Daan Sandee) writes: >In article <306@spam.ua.oz> wvenable@spam.ua.oz (Bill Venables) writes: > >[ story about wedgebills being distinguishable by voice only ] > >>More recently the two have been re-classified and are now regarded as >>conspecific, although such are the vagaries of academic pigeon-holing >>I can't say for how long. :-) >>Regards, Bill Venables. > >Interesting. The A.O.U. (that's American, not Australian) treats two >populations as distinct species if they, under normal circumstances, >do not significantly interbreed. Whether they are sympatric or allopatric >is not really an issue, although it makes the determination of the degree of >interbreeding much easier if they are allopatric. I don't think the A.O.U. is acting this way. It is the *sympatric* species that are easier, since they can be observed in the field, and their interbreeding, or non-interbreeding, can be observed directly (usually). But allopatric species (which cannot by definition interbreed in the wild because they do not come in contact in the breeding season) are lumped or split, based on whether it is believed that they would interbreed if they came into contact in the wild. And if the interbreeding would lead to blending, establishing a cline with a hybrid zone containing no parental phenotypes. So, the Florida and Western populations of "Scrub Jay" are considered to be subspecies. European and American populations of Long-eared Owl. Etc. > From your description, >it sounds as if the wedgebills should be regarded as two species. >In the U.S., the only recent case of a voice-based split is the Traill's >Flycatcher, which was split into Alder and Willow Flycatcher. The two >species have a largely similar distribution, but within that area prefer >different habitats. They can (apart from choice of habitat) be distinguished >by song only - well, sort of ; actually, the songs aren't all that different. > Recently, the American O.U. has been using voice as a more important criteria for allopatric yet morphologically very similar forms. Thus, our Brown Creeper is now Certhia americanus, having been split from the European species because whereas it is morphologically very similar to Tree Creeper (C. familiaris), the voice of americanus is very similar to the Short-toed Creeper of Europe. The fact that "they" have not lumped Marsh Tit with Black-capped Chickadee is based on distinct voice. The spit of Western Flycatcher (Empidonax diffficilus) into Cordilleran and Pacific-slope Flycathcers (**TERRIBLE** English names, by the way!!) was largely voice- based. >I can think of no example in American ornithology where two species that >were distinguishable by voice only, have been lumped. > And, the cynic sez: There haven't been any voice-based lumps yet, only because voice-only-based splits are so new. Just give them time!! >Daan Sandee sandee@sun16.scri.fsu.edu >Supercomputer Computations Research Institute >Florida State University, Tallahassee, FL 32306-4052 (904) 644-7045 David Mark dmark@acsu.buffalo.edu
sandee@sun13.scri.fsu.edu (Daan Sandee) (06/27/90)
In article <310@spam.ua.oz> wvenable@spam.ua.oz (Bill Venables) writes: >In article <151@sun13.scri.fsu.edu> sandee@sun13.scri.fsu.edu (Daan Sandee) writes: >>Interesting. The A.O.U. (that's American, not Australian) treats two >>populations as distinct species if they, under normal circumstances, >>do not significantly interbreed. > >If you add "in the wild", that was my understanding of the official >RAOU position also. However this is clearly not the full story. There >are many examples in Australia of sedentary birds which have a range >consisting of several discrete areas, sometimes hundreds of kilometers >apart, between which migration, and hence interbreeding, does not >occur, and yet they are still regarded as a single species. To name The exact definition does include the words "in the wild" but my wording "under normal circumstances" also indicates "in the wild". I would not regard captive breeding as "under normal circumstances". North America also has species with disjunct sedentary populations which do not interbreed and yet are regarded as one species. The Florida subspecies of the Scrub Jay is isolated from its Western relatives by about a thousand miles. So the AOU does not follow its own definition ; yet it is the definition that is deficient here, for nobody is really suggesting that the Florida Scrub Jay should be a separate species purely on the basis of geographically disjunct populations (allopatry). > >The determination of sepcies status is a strangely contentious issue >in Australia, and some rather iconoclastic revisions have recently >been suggested which are generating a good deal of heated debate. Is >this an antipodean peculiarity or is it the case everywhere?-- You're telling me! Speciation has always been a hot topic both among professional taxonomists and among hard-core birders who are interested in the length of their life lists. And recently, DNA research has come up with suggestions of dramatic changes in taxonomy - mostly at higher levels, though ; the changes at the species level, though interesting enough to us amateurs, will be relatively minor. But it will take another ten years at least before the scientists have even decided how to handle the factor of DNA research in taxonomy. Daan Sandee sandee@sun16.scri.fsu.edu Supercomputer Computations Research Institute Florida State University, Tallahassee, FL 32306-4052 (904) 644-7045