Oaxaca at Christmas

Since the last blog post at the end of our 2021 road trip, we’ve been in El Paso, and most of my time has been spent doing research and planning for 2022. This has been made much more complicated by the pandemic for several reasons. First, accessability of destinations, such as remote areas of Canada, is uncertain. Second, COVID increased interest in camping and purchases of RVs, which seems to have translated to reduced availability of campsites. We had intended to visit Florida for a few months this winter, but found that campgrounds that previously required reservations just a few days to a couple weeks ahead, were instead fully booked several months in advance. Our nomadic lifestyle really does seem to be imperiled by the combination of more people camping, and more campgrounds requiring that all sites be reserved online in advance.

At the end of November, we spent five nights in Big Bend National Park for my birthday. One day we hiked most of the Lost Mine Trail, where we found two principally Mexican plants at the edge of their ranges: Loeselia greggii, a mint known only from one county in the U.S.; and Arcytophyllum fasciculatum,  an obscure shrub occurring in six counties. We also finally made it to Closed Canyon, within Big Bend Ranch State Park, west of the national park; on our previous attempt earlier in the year, we were turned back by hail and flooding. Here we located two individuals of the scarce shrub Holacantha stewartii, which is found in just two counties. It seems to be composed almost entirely of stout spines, and is one of several plants called Crucifixion Thorn. Finally, we saw the grass Cathestecum erectum, which grows on calcareous substrates; like the other three plants mentioned above, it represented a new genus for us.

We found out about seven weeks ahead of time that our birding tour to Oaxaca, Mexico with Field Guides, Inc. actually would go! We scrambled to reserve flights, which at that late date were in short supply and extremely expensive ($4500 – $5000 for the two of us). Fortunately, via a combination of transferring and buying frequent flier miles, I was able to get this down to about $2000, but we hope this is not going to be the new normal.

We flew down a day early on Dec. 18, and were taken around by local guide Edgar del Valle on the 19^th. The main tour ran 6 days, and we flew back on the 26^th, after having COVID tests on Christmas Day. We signed up for this trip in December, 2019, with our good friends Terry and Rhys Harrison, from Victoria, British Columbia. Little did we know that there would be no international travel for any of us during that two-year interim period.

Oaxaca is situated in a high valley ringed by mountains, in southern Mexico. It has an unusual concentration of about 29 bird species that are endemic to Mexico; of these, we saw 21. The tour visited elevations from about 3000 feet to 10,000 feet, sampling habitats including, from low to high elevation: a desert wash on the Pacific Slope with many columnar cacti; arid scrub on the valley floor and lower slopes; deciduous oak woodlands; and pine-oak forests with a number of epiphytic plants growing on tree branches. The weather was perfect and there were no bugs.

Our personal list for the trip was 167 species of birds, of which 35 were lifers. We had another 14 new non-avian species, mostly plants. The small state of Oaxaca has over 10,200 species of native vascular plants (compared to ca. 16,100 in all of North America north of Mexico), but we did not do much botanizing due to limited time and lack of a comprehensive reference for identifying the flora.

Some of our favorite new birds were: Gray silky-Flycatcher, Red Warbler, Slaty Vireo, Bridled Sparrow, Mexican Violetear, Golden-browed Warbler, Collared Towhee, and Cinnamon-bellied Flowerpiercer. We also saw several familiar species better than we had ever seen them before; these included Flammulated Owl, Rose-throated Becard, Hook-billed Kite, Tufted Flycatcher, and Crescent-chested Warbler. In addition to subtropical birds, we saw many wintering songbirds from farther north, including a dozen species of wood warblers. Hermit Warbler, which breeds in coniferous forests of the Pacific Northwest, was remarkably numerous.

There are a number of interesting archaeological sites in the region, of which we visited three: Dainzu, Mitla, and the astonishing Monte Alban. We also saw a demonstration of textile dyeing and weaving, and toured a traditional mezcal facility. Finally, it was a real treat to see the largest diameter tree in the world, El Arbol del Tule, a gargantuan Montezuma Baldcypress. The tree has dramatic flaring buttress roots, but the area of its cross-section can be used to compute an equivalent diameter of about 31 feet, slightly greater than that of the stoutest sequoia. Its height is around 116 feet, and its age is not known accurately but it is likely around 1500 years old.

Our plans for 2022 remain up in the air. We are supposed to go to Ghana (West Africa) in March and New Zealand in November, but have no idea whether these trips will happen. Tentatively, our road trip will be to the eastern U.S., with emphases on finding new vascular plant genera and canoeing. Happy new year to all!