Birding the Casa Grande Ruins and the Agricultural Wasteland of Pinal County, AZ

Casa Grande and the agricultural fields of Coolidge, AZ -

84 miles. It's 84 miles from my office at Saguaro National Park's Desert Learning Center to Casa Grande National Monument in Coolidge Arizona. What that really means is a 2:45am wakeup at my camp on Redington road, high above Tucson to be to be on site by 5:30am for surveys. I was to spend the next two days surveying the birds of Casa Grande Natl Monument. I must admit, I wasn't expecting lively ecology, as the monument is a cultural resources park entirely surrounded by agricultural fields. This notion was to be an erroneous assumption as I was happy to find out. Casa Grande is a massive pueblo structure which was built a matate's throw from the Gila River, in the ancestral farming lands of the Hohokam people. Built sometime in the 1300s, the ruins were first described by Father Kino in the 1600s, and was a well known land-mark in the region for the next 300 years, finally coming under federal protection in the 1890s - early in our nation's attempts to preserve cultural resources. By the 1930s it had become a National Monument, during which time a large pavilion was built over the ruins to preserve the structure's relatively fragile adobe walls. The monument is one of the smallest in the Sonoran Desert Network, surrounded by urban sprawl and agriculture. Highlighting this point, the park's boundaries are formed by two busy state highways, a walmart, a safeway, and a large industrial agriculture irrigation canal. Within the monument, the vegetation is sparse, primarily consisting of aromatic Creosote bush (Larrea sp), with small bosques of mesquite growing within depressions in the landscape, some of which are probably ancestral ball-courts.

Potsherds on the desert plain surrounding Casa Grande.

I often get to see these monuments and parks before anyone else shows up to work, a nice time for a morning stroll!

The sparse habitat and surrounding urban setting makes for interesting bird compositions; lots of species typically associated with agricultural fields, mourning, white-winged, and Eurasian-collared doves, pigeons, lots of blackbirds (Icterids), and a handful of desert residents. Driving up to the monument at 4:00 am, my mind was on one of the site's more interesting species, some burrowing owls that were reportedly living in some Arizona State Game and Fish - created burrows. The reports did not disappoint, as I found at least 3 individuals, one of which was very bold and incredibly photogenic. To find a Burrowing Owls in a heterogeneous landscape, you must let your imagination run wild and turn every stump, rock, and grass clump into a potential owl. Luckily the first individual I found was perched on a large dead mesquite snag. I waited until the transect was complete to try and get some photos, I was really pleased with the results! A caution with Burrowing Owls, during the nesting season owls can be disrupted by approaching their burrows, these individuals were far from their burrows foraging and not too bothered by my presence (from a considerate distance away). 

Burrowing Owl, Casa Grande NM, Pinal Co., AZ

Burrowing Owl, Casa Grande NM, Pinal Co., AZ

Some other cool birds in the park included a migrating Wilson's Warbler hanging out in one of the Mesquite bosques near the Visitor's Center. It was great to see a colorful neotropic migrant like this surrounded by so much development. The Wilson's wasn't alone as a neotropical migrant, Lucy's, Audubon's, and Orange-crowned Warblers were all found within the park on the first morning, each heading for greener pastures to the north.

Wilson's Warbler, Casa Grande NM, Pinal Co., AZ

The monument housed another fun species, although these were not feathered, they attracted a lot of attention - Round-tailed Ground-squirrels. These energetic and coy ground-squirrels lived in a drainage grate within the parking lot and were a lot of fun to watch come in and out of the grate, like a living incarnation of a 'whack-a-mole' game.

Round-tailed Ground-Squirrels, Casa Grande NM, Pinal Co., AZ

While the ruins have been unoccupied by humans for some hundreds of years, plenty of Arizona's wildlife still call it home. Like many other large metal awnings in southern Arizona, a pair of Great-horned Owls were utilizing the structure as a diurnal roost, while the ruins themselves was acting as a nest. While I was not able to find the baby (the staff informed me that at least 1 owlet was tucked away into the ruin), the two adult parents were fast asleep high in the metal roof.

Great-horned Owl roosting above the ruins.

In all, I ended up seeing 39 species at Casa Grande over the course of two days, far more than I expected, with a few oddities brought in by the desert canal, like White-faced Ibis, and Great-blue Heron, strange sights to see flying over a desert plain.

Saguaro in bloom, Casa Grande NM, Pinal Co., AZ

There are a few mighty Saguaros outside of the visitor center, this was probably a much more common vegetation type here in the area at the time of occupation by the indigenous peoples. Today the Saguaros have been cleared for row crops and hay fields, with a few scattered across the rocky hillsides that border the valley on slopes too steep for the plow. Sometimes it takes a relict plant like this to make one realize just how sweeping landscape changes can be. In a hundred years period we've cleared the beautiful and lush Sonoran desert and with our aquaduct projects, river diversions, and laser-leveling combines we've made enough hay to fed all of the dairies and feedlots in the west. Aldo Leopold wrote about relict patches of tall-grass prairies growing in old cemetaries in the northern Great Plains. Wildflowers and economically un-desirable grasses, the last of their kind spending out their days in a retirement home of sorts. Leopold speculated that some of these native plants would probably disappear into oblivion as these last relicts were put under plow or take out for a highway widening project - you know, progress. As I drove back to Tucson, this point was highlighted when my truck was hit with the dust-storm from a combine tilling up more of the fragile desert soil. While we humans have certainly created economic prosperity from what was historically an arid land, only able to support small bands of people, we're also using our natural heritage at an alarming rate. Desert soils blowing away, desert plants disappearing, and the river's of the west dying out here in the agricultural fields of central Arizona. Weeks later I would drive north of Casa Grande on my way north and drive across a bridge, under which was a dry dusty wash. The sign informed me this was the Gila River. The mighty Gila that carves it's way through those blue mountains of southwest New Mexico goes to die in the desert of Arizona, to feed Phoenix's growth and golf courses, to grow hay and row crops. Casa Grande represents a 700 year old structure that was built in support of a vibrant farming culture that relied on the Gila, their diversions and ditches were probably modest, built with 13th century technology. While we'll never get back to that way of life without a push and a shove, sites like Casa Grande National Monument can at least act as a relict of 'worthless' desert creosote plain, reminding us what places like the Gila River valley once looked like.

The future is blowing in the wind. Soil Erosion from a combine in the ag-lands of Pinal Co., AZ