Those that learn my posts repeatedly — and a few current feedback have assured me that you’re, in reality, on the market — will know that previously couple of weeks I’ve travelled between the 2 locations on the planet that I do know greatest. Final week, I returned to Morelia, Mexico, my house for the previous 30 years, from twelve days within the San Francisco Bay Space, the place I spent my childhood and teenage years. It is a four-hour flight, touring some 3,400 km/2,100 miles, and in addition one fifth of the gap from the Equator to the North Pole.
This appreciable distance is why I’m at all times shocked to see so lots of the similar species in each locations. Whereas in California on this journey, I noticed 75 species. 35 of them are species I may also see simply in or close to Morelia. Of the 112 species on my present California life listing, 59 are additionally frequent round Morelia.
Of coure, a few of these species will be seen in each locations as a result of they migrate from up north to central Mexico. However these are surprisingly few. In actual fact, 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 shocking 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 appear in Mexico. However they’re nonetheless thought-about the identical species.
So right here’s my moderately unscientific principle 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. Because of this, each Michoacán and the San Francisco Bay Space solely ever obtain snow at their very highest altitudes. Each areas sport an excessive amount of very comparable pine-oak forest, although 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, lots of the oaks in California sport small, waxy, water-saving leaves. Oak leaves in Michoacán have a tendency extra to the basic Roman oakleaf-crown form. However the central California coast’s signature Monterrey Pine is remarkably much like the Michoacán Pine. Each are inclined to develop into tall, moderately rangy timber, with extraordinarily lengthy needles. Despite their obvious similarity, they aren’t shut family, because the Monterrey Pine grows clusters of 2-3 needles, and the Michoacán Pine bundles 5 needles. Convergent evolution strikes once more.
Through the years, I’ve managed comparative images 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 seems to be 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 may effectively 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 rather more strongly patterned, and in addition present different variations. My Nationwide Geographic Area Information means that they quickly could also be break up into two separate species. Please let or not it’s so.
Michoacán
California
Noticed Towhees have remained a single species regardless of my a number of years of advocacy, from the platform of 10,000 Birds, for his or her long-overdue break up. Truthfully, 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 be aware, to ensure that that michoacano Steller’s Jay on the high 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 can be a Steller’s Jay. I repeatedly noticed these birds round my sister’s house, close to sea degree, in California. However I’ve by no means seen them under 3,000 m/10,000 toes, in Michoacán.
Autor Paul Lewis
