I was awake at 4:30, so made myself a cup of coffee and - because the Magnuson Hotel had no breakfast - some instant oatmeal before running out to the San Pedro House, where the Friends of San Pedro maintain feeders, and docents from the San Pedro Riparian National Conservation Area conduct weekly birding walks. Pete Siminski was there when I arrived, beginning the bird count, and hoping for a view of the Ruddy Ground Dove that has been seen recently.
The House was originally a ranch house, and now houses the Friends’ visitors’ center, a gift shop and offices.
The San Pedro riparian area is administered by the US Bureau of Land Management, contains about 40 miles of the upper San Pedro River, was designated by Congress as a National Conservation Area (NCA) on November 18, 1988. The primary purpose for the designation is to protect and enhance 57,000 acres of the desert riparian ecosystem along 40 miles of the San Pedro River. This is a bare remnant of what was once an extensive network of similar riparian systems throughout the Southwest.
There was a native plant garden at the House. I had to learn this species in my OSU Range Ecology class back in the 70s: Big Sacaton (Sporobolus wrightii) is a warm-season perennial bunchgrass, generally found on floodplains and alluvial soils. It can grow to 6 feet tall, and used to form extensive grasslands in the Southwest prior to the introduction of livestock grazing. As an aside, warm-season grasses are known as C4 Plants. This is because they use the four-carbon compound called Phosphoenolpyruvate, or “PEP”, carboxylase in photosynthesis. In grasses PEP carboxylase is a photosynthetic enzyme that can “attract” CO2 more efficiently than cool-season “C3” plants, and allows the stomata of the plant to be closed more often. Having the stomates closed more often makes the plant more drought resistant which allows it to grow in the southern regions where there are higher temperatures.
We searched around the feeders, looking for the dove, but this morning’s wind kept many of the sparrows and other birds holding tight to cover. So, we walked the birding route which loops south past a couple of ponds that remain from historical gravel mining, parallels the San Pedro River, and returns to the House.
The San Pedro River is the last remaining undammed river in the southwest United States, and supports some wonderful biological diversity in this desert land. The river currently is running slightly high due to the recent monsoon rains, but it is obvious from the scarring on the riparian trees that when the floods come, they can be swift and violent.
As can the winds. There had been a few storms with enough gusts to have taken down some of the trees altogether.
We saw a number of the ‘common’ local birds, many of which are not seen commonly anywhere near my home in western Washington State. Some are.
The wet monsoons have contributed to conditions favorable for the local tarantulas, which go into breeding mode with the fall rains. This one might be the Aphonopelma vorhiesi, as it is much darker than others (c.f. the Arizona “blonde” tarantula A. chalcodes) I’ve seen in the Southwest. Hard to say. The Aphonopelma of North American are poorly known. Although many species have been described, few specimens can be properly identified either by using available keys or by wading through species descriptions. Most of the identifiable specimens belong to species found in Mexico or Central America that are easily recognized by unique color patterns. Correct identification of specimens collected within the United States is often suspect since determinations must be based on the process of elimination using collection dates and locality data in combination with coloration, coxal setation, and metatarsal scopulation. Can’t get that from a photo . . .
Another arthropod out in fair numbers today was the Juno Buck Moth Hemileuca juno. In the fall, adults emerge from their cocoons in the morning and mating occurs in the afternoon. Females lay eggs from late afternoon until sunset; the eggs overwinter and hatch in April or May. Young caterpillars feed in groups on mesquite buds and flowers in the mornings, usually resting among branches during the afternoons. Development is rapid, and caterpillars spin cocoons in leaf litter in May or June. Most of these will emerge as adults the next fall, but some may delay emergence for up to 4 years.
The group of birders returned to the San Pedro House to find, roosting among a few Inca Doves, a female Ruddy Ground Dove, my Life Bird No. 663 in the ABA area. There has been a male of the species accompanying her, but he, the brighter ruddy-colored of the two, wasn’t seen by us today.
This species is a fairly rare wintering bird along the southern tier of United States, although being fairly common from Mexico south as far as Argentina. The species’ “Latin” name is Columbina talpacoti, with talpacoti apparently being an indigenous name for the bird.
Our group saw 46 species today, and I was pleased to meet Rob Woodward, who is doing his own birding Big Year. He keeps his Blog much more up-to-date than I’ve been able to, and was apparently among the throng of birders at the Lower Rio Grande Valley Birding Festival two weeks ago. We didn’t have the chance to bird together then, but made up for it today.
The walk was over a little before noon, so I made the drive over toward Tubac, Arizona, where the Rose-throated Becards have been seen recently. This will be my last attempt to find this “nemesis” species for me this year. I arrived at the Anza Trailhead on Bridge Street and walked north where a pair of the Becards has nested the past few years. The wind was blowing pretty strongly, and I saw few birds of any kind - and could hear practically none over the rush of wind in the cottonwood leaves. In fact, I was sort of concerned that the gusts might bring down some of the trees.
I gave up at dusk, and drove into Nogales, checking into the El Dorado Inn. This place is clean, but pretty bare-bones. It was at this point that I realized I’d left my new Coleman cooler and drinks (beer!) in my room in Sierra Vista when I checked out of the Magnuson Hotel this morning. I called their front desk, but the cleaning staff had not reported a cooler (!). I was tired and hungry so went down to the nearby Denny’s for supper. If you eat here, note that they will not let you know that they partner with AARP to offer seniors a discount… You have to “remind” them.
San Pedro RNCA eBird checklist is Here
Tubac De Anza Trail eBird checklist is Here
