Sonoran Desert Wildflowers

We left El Paso on Feb. 22, 2½ weeks after returning from Ecuador, for a 7½ month trip through western North America, complementing the focus of 2017 on the center on the continent, and 2018 on the east. The primary goal of the trip is to explore Alaska and northwestern Canada, which we last did in 1999. Our route on the way north will be through the Pacific states, and on the return we will sample locations in the Great Basin.

Our first night of camping, in City of Rocks State Park, in New Mexico, was a rude awakening, as we arrived in a blowing snowstorm, and found that the furnace was not working. This posed the risk of the water system freezing overnight (not to mention our suffering the same fate!). Fortunately, disconnecting and reconnecting the power fixed the problem, probably by “resetting” the sail switch (which is like a weathervane, confirming that the blower fan is moving a sufficient quantity of air for it to be safe to ignite the furnace). We have had no more problems since, which is a good thing, as we have had many very cold nights.

City of Rocks is a volcanic deposit that has weathered into interesting shapes and formations. The rock is tuff, formed from hot volcanic ash and debris that welded together from the heat. The weathering was principally along vertical cracks resulting from cooling, creating “alleyways” and leaving pillars, thus resembling a cityscape. We had a nice selection of birds and plants here, including a cholla we had not seen before.

Our next stop was the Animas Valley in southwestern New Mexico. This is the only area in the U.S. where White-sided Jackrabbit occurs, and we had looked for it once before, unsuccessfully. Numbers are dwindling and the population is thought to be well under a hundred animals, with most being located on private lands. Although the thermal scope was helpful, the few jackrabbits we detected from the one public road were distant and not cooperative, and so we did not get a positive identification. Javelina and Pronghorn were consolation prizes.

We next camped at a water hole near Portal, AZ, in hopes of live-trapping several rodent species we had not seen before, but with the continuing cold weather, there was no above-ground activity of small mammals. Quite a number of our planned stops in the first three weeks of our trip were chosen because of the mammalian possibilities, but with the cold weather, we largely redirected our efforts towards plants. We did stop at Cave Creek Ranch in Portal, which has a nice feeder setup, and enjoyed Yellow-eyed Junco, Arizona Woodpecker, Bridled Titmouse, and many other birds.

Continuing west, we birded at Twin Ponds, in Willcox, AZ, seeing Mexican Duck, a bird formerly regarded as a distinct species, but now treated as a subspecies of Mallard because of hybridization. Recent molecular evidence indicates it is more closely allied with Mottled Duck than Mallard (something I always thought was the case from seeing them in the field), so there may be another revision of its taxonomy in the future.

In Tucson, we met up with our friends Connee and Bob Reau, whom we met on a tour to Brazil in 2008. We had dinner one night, and went birding the next, which was Eileen’s birthday. Bob noticed a freshly dug hole from a Botta’s Pocket Gopher in Agua Caliente Park, so we pushed a bit of the excavated dirt back into the entrance, and waited about five minutes until the pocket gopher pushed the dirt out to re-open the hole, giving us excellent looks! There were lots of nice birds about, including Vermilion Flycatcher, always a favorite.

In Sabino Canyon, we found quite a few native wildflowers, including a lovely new species for us, Streptanthus carinatus (Lyreleaf Jewelflower). We knew there were excellent displays of flowers at the western end of the Sonoran desert, in southern California, and seeing decent flower diversity in Tucson, near the eastern end of the Sonoran Desert, gave us hope that the entire Sonoran Desert would be good this year, thanks to winter rains. And, in fact, that is just what we experienced – two weeks of beautiful desert wildflowers!

Leaving Tucson the next morning, we birded at dawn at the Sweetwater Wetlands, seeing Virginia Rail, Sora, and Abert’s Towhee well. As we drove west on route 84 towards our next destination, Organ Pipe National Monument, we began seeing excellent wildflower displays of purple lupines, orange globemallows, and yellow composites.  Once in Organ Pipe, I starting keying many of the desert plants, using the Kearney and Peebles “Arizona Flora”, unfortunately outdated as it was published in 1960. We spent one day in the Quitobaquito Spring area, where we had a fantastic experience with Underwood’s Mastiff Bat in 2015. There is a published paper listing all the plant species in the immediate vicinity of the spring, which helped greatly in identifying things more quickly. In total, over 3½ days in Organ Pipe, we found 7 new plants and one new fish, the Sonoyta Pupfish.

After swinging by Yuma, AZ to stock up on food, we continued to Kofa National Wildlife Refuge (NWR), which protects a Desert Bighorn Sheep population in mountainous terrain in southwest Arizona. We spent several nights camped here in beautiful locations. Our best bird here was Black-chinned Sparrow on a 6-mile hike in Kofa Queen Canyon. We found five new plants in three days, including the rare Kofa Barberry, Berberis harrisoniana, the worldwide range being only four counties in southwest Arizona, and the Whipple Mountains along the California side of the Colorado River.

Our next stop was Oxbow Recreation Area, south of Blythe, CA, where an isolated oxbow lake occupies the original channel of the Colorado River. This site has occasionally had Arizona Myotis, a scarce bat, roosting under the bridge over the river, but none were present when we visited, and recording after dark yielded only Mexican Free-tailed Bats. We enjoyed birding nearby Cibola NWR, where we found a Eurasian Wigeon and encountered the largest flock of Yellow-headed Blackbirds we had ever seen, probably about 200 birds.

Continuing west into Riverside County, CA, we drove some distance on the Bradshaw Trail, a sandy road running almost from the Colorado River to the Salton Sea. We have had good plants and good bats along this road in the past. We camped one night at Corn Springs, just south of I-10 and east of Joshua Tree National Park. The wildflower displays along the entrance road were outstanding, with yellow Chylismia brevipes (evening primrose family) and purple Phacelia crenulata (Notch-leaved Phacelia) dominating, but many other species also present. Brandegea bigelovii (Desert Starvine), a twining vine in the gourd family, with tiny flowers and cute leaves, covered shrubs along the roadside.

There was a Gila Woodpecker in the few remaining native California Fan Palms at the spring; though common at places around the Salton Sea and along the Colorado River, this is a bit of an outpost for the species. There were also a few Lawrence’s Goldfinches flying around; we had been hearing this nomadic and unpredictable species occasionally since Organ Pipe. This was the first area where we encountered major flights of the Painted Lady (Vanessa cardui), a migratory butterfly. The species winters in Mexico and in early spring moves north into the western U.S. The magnitude of the flight, and the northern extent of its incursion, vary from year to year. This was the best flight in many years (some sources say since 2005). While difficult to quantify, I would guesstimate that the northwesterly flight had densities of several butterflies per square yard, for miles upon miles.

We next spent a day birding around the south end of the Salton Sea. This body of water lies at the bottom of the Salton Sink, a depression with no outlet to the sea. The water level is about 226 feet below sea level. It is saltier than the ocean but less so than Great Salt Lake. The best birding is mostly where rivers flow into the sea, the fresh water diluting the salts and irrigation runoff from agricultural areas. Red Hill, at the Alamo River mouth, was in the middle of a reclamation project, and was mediocre (but the project may significantly improve the birding in the future). However, we enjoyed great views of Ridgway’s Rail and Sora there. The Unit 1 area, near the New River mouth, had a lot of shorebirds; the number of accessible impoundments has been increased since we last were there, a welcome change. We camped at Finney Lake, where we once heard Black Rail and saw Fulvous Whistling Duck, but Clark’s Grebe was the best bird we could come up with this time. Neotropic Cormorant at nearby Ramer Lake was a real surprise; there are only about a dozen records from California for this species, which generally occurs farther east and south.

Our last Sonoran Desert destination was Anza-Borrego Desert State Park, a favorite place of ours because of its excellent boondocking (i.e., isolated camping away from campgrounds). We spent four days here, concentrating on the diverse wildflower assemblages. Though slightly past peak, the displays were still good, the variety was excellent, and the presence of fruit on many species aided in identification. We botanized primarily in June Wash, San Felipe Wash, and Coachwhip Canyon.

The latter we visited on a hike organized by Tom Chester, an outstanding amateur botanist who is preparing floras of the Anza-Borrego lowlands and the San Jacinto Mountains highlands. Though I had corresponded with Tom by e-mail since 2010, this was our first encounter in person and it was marvelous to finally meet him and get a chance to go into the field together. The entire group was knowledgeable and friendly and we had a wonderful day. Because of their expertise, we saw six new plants, a very high number in a state where we have seen over 3300 taxa. A particular treat during our four days in the park was repeatedly seeing numbers of Hesperocallis undulata (Desert Lilies), a spectacular member of the agave family.

 

In closing, I should note that the outstanding displays in the Sonoran Desert are not an isolated occurrence. Much of southern California received major rainfall this winter, and some areas are experiencing “superblooms”, which have been heavily reported in the media. More on this next time.