"Everyone likes birds. What wild creature is more accessible to our eyes and ears, as close to us and everyone in the world, as universal as a bird?” — David Attenborough

To be clear, deserts represent a challenge for all life, as life as we know it on earth is dependent on the availability of water. Deserts by definition are regions where water is limiting. Nevertheless, life does thrive in deserts and so provides opportunities for naturalists to uncover the various mechanisms for how life has solved these challenges. Some of the highest levels of biodiversity on our planet, including for annual plants, cacti, bees, darkling beetles, and lizards, are found in deserts. Birds can be abundant here as well, but for the most part their richness and numbers are not due to adaptions to desert life, but are due to their ability to avoid and escape the heat and aridity that defines deserts.

Many of our desert birds are only winter residents, breeding further north or toward the less challenging coastal zones or higher mountains. White-crowned sparrows, serenading me now as I write this essay, breed higher in the Sierra Nevada escarpment or along the coast as far north as British Columbia and Alaska. They only inhabit deserts during the mild winter months. Others have populated desert oases but never venture into the surrounding true desert. The Big Morongo Preserve is one of the premier birding sites in California, but if blindfolded and dropped onto the boardwalk trails you would be hard pressed to identify anything that is desert-adapted living there. Due to the presence of an earthquake fault that forces deeper aquifers water to the surface, Big Morongo’s cottonwoods and willows are more reminiscent of a stroll through an eastern deciduous forest. While there is concern that the aquifer is increasingly stressed, not by the cottonwoods and willows but by the surrounding and increasingly thirsty human population, at least in years with ample rainfall water seems unlimited. Birds that breed in that wet forest seem to avoid any of the surrounding desert habitats. Summer tanagers, brown-crested flycatchers, vermillion flycatchers, Virginia rails, Anna’s hummingbirds, Nuttall’s woodpeckers, willow flycatchers, least Bell’s vireos, bushtits, scrub jays, oak titmice, Lucy’s warblers, yellow warblers, lazuli buntings, and more all have been known to breed in those cottonwoods and willows, but none would ever willingly venture into the surrounding desert.

One of the best examples of desert adaptation and avoidance by birds is the phainopepla, a member of the silky flycatcher family, whose other members more typically occupy tropical forests in Central America. Here, in our desert, phainopepla’s spend the winter, consuming mistletoe fruits that are otherwise poisonous to most creatures. Phainopeplas and mistletoe have developed a symbiotic relationship where the mistletoe provides high energy food for the phainopeplas and the phainopeplas “plant” those mistletoe seeds when the birds defecate on palo verde, mesquite, and ironwood branches. Phainopeplas use that high energy food to breed in the early spring, typically nesting in paloverde and ironwoods. Then, when the desert begins to get hot, phainopeplas do something that no other bird is known to do, they fly to cooler coastal oak woodlands and breed a second time in a completely different habitat type. As far as I know no one has documented the same individual phainopepla breeding twice, the same year in those different habitats, but the whole population makes this seasonal shift and it is assumed that the same birds at least occasionally do pull off this exceptional feat.

The list of bird species that are truly adapted to thrive and breed within the North American deserts is relatively small. In the Sonoran Desert giant saguaro cacti appear to be a focus of bird life. Gila woodpeckers, gilded flickers, elf owls, and ferruginous pygmy owls use those thick, water-filled trunks as a refuge from the hot desert summers. Curve-billed thrashers, cactus wrens, and verdins nest in dense cholla gardens, giving them an effective barrier from marauding predators. The wrens and verdins construct dome or funnel-shaped nests that provide effective insulation from the late spring and summer heat. Scott’s orioles will build their woven, basket-like nests in palm trees, Joshua trees or mesquite and ironwoods. The key being some kind of “tree” and the availability of long plant fibers, from yuccas and palms, for weaving their nests. Ladder-backed woodpeckers and ash-throated flycatchers are other birds that venture out into desert habitats, but are limited to where they can find trees, or tree-like structures for building their nests.

The number of bird species who can thrive in a shrub dominated, tree-less desert is smaller still. In the cooler Great Basin Desert Brewer’s sparrows breed and then will winter in the Mojave and Colorado Deserts. Otherwise, in the warm and hot deserts there are black-throated sparrows and black-tailed gnatcatchers, and LeConte’s and Bendire’s thrashers (Mojave Desert) and curve-billed thrashers (Sonoran Desert), and cactus wrens in the deserts that support cactus. Wrens in general seem to have figured out ways to call our deserts home. In addition to the cactus wrens, Bewick’s wrens seem to be able to be comfortable in the slightly cooler Mojave Desert and higher elevations in the Colorado Desert. Canyon and especially rock wrens are common at lower elevations where boulders dominate the landscape. They nest in deep clefts in the rocks, giving them and their young thermal protection from the otherwise lethal summer temperatures. More than any other bird, the “squeaky-hinge” call note of the rock wrens seems to accompany our desert explorations wherever we go.

Across North America, Corvidae, the bird family comprising jays, crows, and ravens seem to be found just about everywhere, except until the past half century, in deserts. Scrub jays thrive where there are oaks and acorns. Steller’s jays and Clark’s nutcrackers take over in the conifer forests. Crows seem to have adopted human landscapes, agricultural, and especially suburban, and urban settings. Ravens can be common in forested lands and along sea coasts, but the early desert naturalists found them, and any of the jay and crow tribe to be exceedingly rare here. Rather than daily sightings, they recorded at best one or two ravens a week. Today it is not exceptional to see a dozen or even flocks of one hundred or more ravens in a single day. The reason for the “explosion” of desert ravens is their adaptability and the abundant food waste created be humans. Open dumpsters behind restaurants, cattle feed lots, and road-killed wildlife provide an abundant, continuously available food supply for ravens. Unfortunately, these now abundant and intelligent ravens have not restricted themselves to our food waste, and some have developed a taste for baby tortoises and fringe-toed lizards. The ravens’ exploitation of these endangered reptiles has resulted in the ravens being vilified and persecuted by humans, when the real problem is us. Some wildlife professionals are developing non-lethal means of discouraging ravens from eating baby tortoises. Being as intelligent as they are, they seem to be getting the message. The ultimate solution is for us to stop wasting food, and stop making our food waste so easily exploited by ravens.

Nullius in verba

Go outside, tip your hat to a chuckwalla (and a cactus), think like a mountain, and be safe.