Arizona Nature --> Sonoran Desert Naturalist --> Sonoran Desert Places --> Mesquite Wash
Mesquite Wash is a rare desert riparian habitat located approximately 20 miles northeast of Fountain Hills, Arizona. Follow the Bee Line Highway, SR 87, a few miles past the Four Peaks turn off, watching for the Mesquite Wash sign. The main wet areas are on the west side of the highway where there is a large dirt parking area. A spring and a 1/2 km long stretch of permanent water lie a short distance down the sandy 4x4 roads leading from the parking area. Tremendous biodiversity in terms of plants, birds, butterflies and aquatic life is easily observed here.
Although these roads are somewhat passable, I recommend walking in. Environmental damage in this area is severe ... the large shade trees and broad sandy washes attract many recreationists many of whom behave irresponsibly. Rubbish, human waste, spent ammunition, spilled motor fuels and lubricants, and numerous eroded ORV trails ... but don't let these hazards and eyesores stop your visit. There are so many fascinating natural observations that can be made here. And when your visit is complete, please write a note to the Forest Service:
View a Slide Show of Mesquite Wash at Flickr.
A view to the west at Mesquite Wash.
Thank you! The forest service and off road vehicle users groups have responded by erecting signs and barriers to keep vehicles out of the most sensitive area. Some sensitive areas are left out, however, and a few riders view the signs and barriers as an afront to their given rights and ride around them straight into the spring area. More policing might be necessary.
In addition there are two watersheds, Rock Creek and Mesquite Wash, that extend well up into the foothills of Four Peaks on the east side of the road. These are reacheable via high-clearance vehicle road -- or better yet hike up the dry wash beds. They are easy to hike for the first few kilometers and offer many interesting things to see. The lower portion of Rock Creek includes a dense mesquite bosque that includes a variety of other trees such as Texas Mulberry. The creek and bosque are vital stopping points for migrating neotropical birds. The Mesquite Wash area also includes deep sandy washes, wash banks, rocky hillsides/bajadas and tallus slopes each with different sets of plants and animals.
View Mesquite Wash in a larger map. The shaded area represent the area designated as Mesquite Wash in this guide.
Despite three years of drought and food scarcity, the twelve-year-old Native Fire Ant (NFAs) colony still had thousands of nest members and a significant class of new recruits nearing maturity. Ant recruits are larvae (grubs) and are white, legless and helpless. These larvae are kept in deep underground chambers where cooler temperatures and higher humidity prevail. Chewed up food from the adult ants foraging is regurgitated constantly for the larvae to feed. During recent hard times the scarcity of food meant the grubs were growing very slowly ... too slow to replace the foraging adults who were aging and dying. And with food in short supply, the numbers of maturing majors (larger size workers with larger jaws and more powerful stings) was also way down from optimum.
Just a week ago a deluge of much needed rain soaked the ground and brought forth numerous plant seedlings and hatching insects ... i.e. food resources desperately needed by the colony. The NFAs had been very busy the past few days foraging ... sending out many workers to search far and wide for food items to return into the nest.
Then this evening, soon after dark, while many foragers were still away, guests arrived at the colony doors. They weren't invited and came so quickly and in such numbers that they quickly dispatched the NFA majors that had been holding sentinel. The guests were blind Arizona Army Ants (AAAs) bearing long sharp mandibles and powerful stings. Long-legged and agile the invaders quickly killed or evaded all defenders on their way down into the chambers holding the young grubs.
The order to abandon the NFA colony came soon there after. Every able-bodied NFA worker and major grabbed one or more of the young grubs and departed the colony nest by an auxiliary exit. Carrying their precious young out and up a nearby cactus, they sought refuge from the marauders at the tips of the highest cactus spines. Any grubs left behind were quickly gathered up by the AAAs and hauled out and back to their own bivouac-colony. Other AAAs pursued the defenders up the cactus where they engaged them in a lethal fight. Usually the AAA succeeded in snatching the grubs away. Some ants leapt from the cactus only to fall into a widow spider's web below. Others dropped their grub-cargo during battle ... on the ground, other AAAs waited for the falling spoils. What's more, there were also several scorpions moving with the invaders and they also preyed upon fallen grubs.
Once the AAAs had a full bounty of booty they broke off the invasion and departed as quickly as they arrived. As dead and dying NFAs littered the ground everywhere, the survivors returned to the colony chambers each carrying a rescued young grub.
Deep in the colony a NFA queen was nonetheless spared as
countless majors and workers defended her against all odds ... the AAAs were
getting what they came for ... the tender young grubs ... and so spared the
queen. For this the NFAs were quite lucky, since the AAAs often spend the
following day bivouacked in the defeated colony's chambers. Left outside in the
withering desert sunshine, such colonies are doomed. In the coming days and
weeks the NFA queen will lead her colony to rebuild and regroup. That she must
for the Arizona Army Ants could well return for the coup d'etat.
This digital photograph of an army ant, Nievamyrmex nigrescens,
was made by Dale, author of Ants of Arizona.
You can find many more pictures of Arizona's tremendous diversity of ants.
This digital photograph of a native fire ant (NFA), Solenopsis xyloni, was also made by Dale, author of Ants of Arizona.
This is a long list because Mesquite Wash is a riparian habitat. Birds likely to be seen with more common birds at top:
Look for Song Sparrows at the margins of dense vegetation adjacent to pools of water in Mesquite Wash or nearby Sycamore Creek. Notice the dark spot at center of chest.
Turkey Vultures can be seen soaring above Mesquite Wash from March to October.
During the winter months they move further south into Mexico.
Upper Sonoran Desert Scrub interspersed with chaparral and well developed riparian habitats and moist springs results in a very diverse mosaic of plant species.
New Mexico Thistle
Lesser Indian Paintbrush
Foothills Palo Verde
Trailing Four O'Clock
Bigelow's Four O'Clock
Hooker's Evening Primrose
Cardinal Monkey Flower
Seep Monkey Flower
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