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some papers on Eastern Towhee call mimicry

some papers on Eastern Towhee call mimicry
By – 3:53 pm
On our drive down to the Jacumba towhee from Northern California two nights ago, Ethan Monk used his iPhone to conduct a google scholar search for literature on Eastern Towhee call mimicry and immediately found one research paper documenting that phenomenon and others documenting mimicry in songs which is well established among many oscines. As several have mentioned on various social media platforms, calls are assumed to be innate (genetically inherited) and not learned as opposed to songs. And thus an Eastern Towhee looking bird uttering a Spotted Towhee call would therefore have to have Spotted Towhee genes. The paper provides examples of Eastern Towhees giving calls of other species which would refute that assumption for that species. It is likely that the complexity of the calls of Eastern and Spotted towhees make them more similar to songs and not completely innate, thus facilitating mimicry. It’s been a great learning experience for many of us pondering the issue of whether the towhee in Jacumba is a hybrid or a pure Eastern. This literature search is a fairly easy task and can yield really interesting papers on many different topics on ornithology. Try it….also you can search SORA, the searchable ornithological research archive where many of the major ornithological journals have archived their publications, with some going back over 120 years. Lots of cool historical stuff to be unearthed and downloaded for free. About fifteen years ago, I found the first Big Day publication by William Dawson doing a big day in Santa Barbara County from 1913, so not all of the papers especially the older ones are technical!! Here are links to the two search engines that I mentioned.https://sora.unm.edu The search engine is a bit picky so not as easy to use as it should be.https://scholar.google.comHere’s the link to the Santa Barbara big day. https://sora.unm.edu/node/95493Here’s a link to the paper on the towhee call mimicry topic (1998). https://sora.unm.edu/sites/default/files/journals/wilson/v110n03/p0431-p0434.pdfNote the final statements copied below from that paper states that more research is needed for other songbird species. Ethan just told me that he looked into it and since that paper was published in 1998, no other research has been published on this topic that he could find. He’s going to contact the first author, Greenlaw, to get his opinion on the recorded calls of our towhee.”This report of call mimicry in Eastern Towhees suggests that sound or social experience may play some role in the development of call repertoires in this species, and in the specific use of mimicked calls in generalized “alarm” contexts. The hypothesis that calls in songbirds are “genetically fixed” (strictly maturational; e.g., Lanyon 1960) needs to be examined using isolation and tutoring experiments on a case by case basis.”Regardless of whether the Jacumba bird is a hybrid or pure bird, it is an amazing record. At this point, I think that the burden of proof is on the hybrid camp with this information that calls may be mimicked, especially given that a hybrid looking like a pure Eastern is likely to be extraordinarily rare and a tiny fraction of the population source of vagrants, narrowing the odds considerably. And if it is a hybrid, it inherited two separate types of calls which is interesting in itself….has that ever been documented before? I’ve heard second hand that the Eastern type call that Ethan recorded is typical of calls away from the contact zone and unlike that of the calls in the contact zone where both species occur. Another tidbit to ponder. have fun,John John SterlingVVVVVVVVVVVVVVVVVV26 Palm AveWoodland, CA 95695PO Box 1653Woodland, CA 95776A530 908-3836jsterling@wavecable.comwww.sterlingbirds.com