Those that learn my posts recurrently — and a few latest feedback have assured me that you’re, the truth is, on the market — will know that previously couple of weeks I’ve travelled between the 2 locations on the earth that I do know finest. Final week, I returned to Morelia, Mexico, my dwelling for the previous 30 years, from twelve days within the San Francisco Bay Space, the place I spent my childhood and teenage years. This can be a four-hour flight, touring some 3,400 km/2,100 miles, and in addition one fifth of the space from the Equator to the North Pole.
This appreciable distance is why I’m at all times stunned to see so most of the identical species in each locations. Whereas in California on this journey, I noticed 75 species. 35 of them are species I can even see simply in or close to Morelia. Of the 112 species on my present California life record, 59 are additionally widespread round Morelia.
Of coure, a few of these species could be seen in each locations as a result of they migrate from up north to central Mexico. However these are surprisingly few. Actually, these 35 species I discussed, solely the Cooper’s Hawk and Warbling Vireo summer time in California and winter within the highlands of central Mexico. Many extra are residents in a single place and migrants in one other, not at all times within the locations you’d guess. A stunning quantity summer time far north, and winter in each California and Mexico. Many are residents in each locations. A few of these look fairly completely different in California, from how they give the impression of being in Mexico. However they’re nonetheless thought of the identical species.
So right here’s my somewhat unscientific idea on all this overlap: Apparently, an altitude of 1,900 m/6,300 ft, at Morelia’s latitude of 19.70 north, is similar to sea degree, at San Mateo’s extra northerly latitude of 37.77 north. In consequence, each Michoacán and the San Francisco Bay Space solely ever obtain snow at their very highest altitudes. Each areas sport a substantial amount of very related pine-oak forest, though Michoacán is dry within the winter and moist in the summertime, and California has the precise reverse sample.
Maybe as a result of the dry season in California coincides with its hottest months, whereas Michoacán’s summer time warmth is moderated by every day rains, most of the oaks in California sport small, waxy, water-saving leaves. Oak leaves in Michoacán have a tendency extra to the traditional Roman oakleaf-crown form. However the central California coast’s signature Monterrey Pine is remarkably just like the Michoacán Pine. Each are likely to develop into tall, somewhat rangy bushes, with extraordinarily lengthy needles. Regardless of their obvious similarity, they don’t seem to be shut relations, because the Monterrey Pine grows clusters of 2-3 needles, and the Michoacán Pine bundles 5 needles. Convergent evolution strikes once more.
Over time, I’ve managed comparative pictures of a number of of these species talked about above that are residents in each locations, however look barely or very completely different. The Bushtit appears wildly completely different. Mexican male Bushtits have jaunty black masks. The second photograph is of a Mexican feminine, however change that eye to black, and it might properly signify a Californian Bushtit.
Male in Michoacán
Feminine in Michoacán, or one thing like a male in California
Bewick’s Wrens look solely barely darker up north than they do in Mexico. However I’m a witness that their songs sound very completely different from one place to a different.
Michoacán
California
Brown Creepers like each the abovementioned Monterrey and Michoacán Pines. The Mexican ones are far more strongly patterned, and in addition present different variations. My Nationwide Geographic Subject Information means that they quickly could also be cut up into two separate species. Please let it’s so.
Michoacán
California
Noticed Towhees have remained a single species despite my a number of years of advocacy, from the platform of 10,000 Birds, for his or her long-overdue cut up. Actually, how can these two birds be of the identical species? When will I get justice? And why should we name our spotless birds right here “Noticed Towhees“?
Michoacán
California
As a ultimate word, to ensure that that michoacano Steller’s Jay on the prime of this put up to be a Californian Jay, it must lose a all the sunshine markings on its face, in addition to a little bit of crest top. However I’ll settle for that it nonetheless could be a Steller’s Jay. I recurrently noticed these birds round my sister’s dwelling, close to sea degree, in California. However I’ve by no means seen them under 3,000 m/10,000 ft, in Michoacán.
