WILDLIFE
LA OSA’S NATURAL WONDERS
WILDLIFE OF THE SOUTHERN ARIZONA BORDERLANDS
Rancho de la Osa is located adjacent to the 117,464-acre Buenos Aires Wildlife Refuge. Known for its high desert grasslands, it also features riparian areas with seasonal marshlands, meadows, cottonwoods and mesquite groves, providing rich habitat for a large variety of wildlife. It’s a birder’s paradise with a tremendous array of species including different orioles, tanagers, herons, ducks and hawks. Though bears and Mexican gray wolves are no longer in the area, mammals like pronghorn, mule deer, mountain lions, and javelinas still roam. There have even been sightings of the elusive jaguar. Discover more with self-guided hiking and eco-education about the surrounding area during your visit to La Osa.
For a closer look at some of the wildlife we see nearby the ranch on trail cameras, check our our Flickr account!
BIRDS OF THE BUENOS AIRES
Our ranch and surrounding areas are home to the endangered Masked Bobwhite Quail and 300 other species including herons, gray hawks, owls, orioles, vermillion flycatchers, loggerhead shrikes and golden eagles.
SPECIES TO LOOK FOR:
Greater Roadrunner
Gambel’s Quail
Great Horned Owl
Crested Caracara
Vermillion Flycatcher
Loggerhead Shrike
Golden Eagle
Green-Winged Teal
Verdin
Varied Bunting
Gila Woodpecker
Say’s Phoebe
Anna’s Hummingbird
Sora
Western Kingbird
Pyrrhuloxia
Lazuli Bunting
Northern Harrier
Vesper Sparrow
Blue Grosbeak
and so many more!
NOTABLE SPECIES IN THE AREA
MASKED BOBWHITE QUAIL
The masked bobwhite quail is a subspecies of the northern bobwhite endemic to the Sonoran Desert. The males have a cinnamon breast with a black head and throat and white stripe from the edge of the eye down to the neck. The females are colored in subtle buff, mottled earth tones and have a white stripe originating from the side of the eye.
This quail subspecies is a listed endangered species and the sole reason Osa’s neighbor, the Buenos Aires National Wildlife Refuge exists. In 1985, the Department of Interior purchased the former cattle ranch exclusively for masked bobwhite quail recovery. Previously, the Buenos Aires was a cattle ranch that changed hands much like La Osa in the late 1800s and early 1900s. From the 1920s to 1950s, it was the home to a prize-winning quarter horse racehorse breeding operation with the Gill family.
The quail's historical range had been from southeastern Arizona to northern Sonora, Mexico. Over the years, the once open, lush grassland had degraded to a mesquite-dominated landscape because of drought and livestock. The masked bobwhite was presumed extinct in the U.S. by the 1920s. Some individuals still lived in Sonora and were the impetus for attempting to restore the quail to U.S. lands. The first attempts occurred in the 70s and 80s. There was some success, but ultimately, the reintroduction program failed due to poor land management.
In addition to seeding, erosion control, and prescribed burning, the refuge has been mechanically removing mesquite trees to open the land back up for grassland restoration to aid masked bobwhite recovery. Since the 80s, BANWR has run a breeding and reintroduction program for the quail. BANWR has a breeding facility in nearby Arivaca and also receives chicks from a facility in Oklahoma.
Masked bobwhite chicks are fostered by a northern bobwhite (captured wild in TX and OK) male because they are more common. Before their release into the wild, the foster dad and his chicks live in an outdoor acclimation pen. Upon release, the foster dad continues to educate the young birds on where to find shade, shelter from predators, and where and how to hunt for food.
The quail can be observed in a public acclimation pen on the BANWR Visitor Center's Ranch Loop Trail.
Cactus Ferruginous Pygmy Owl
The Cactus Ferruginous Pygmy Owl is a subspecies of the pygmy owl. A short and feisty raptor, the owl stands at six inches tall and is found in southern Arizona and Texas, and northern Mexico.
In 2023, the owl was re-listed under the United States Fish and Wildlife Service’s Endangered Species Act as a threatened species. The owl had previously been listed as endangered in 1997 but then was de-listed in 2006 because the species was seen as thriving in Mexico at the time.
The owls utilize saguaro cacti and mesquite woodlands habitats. They do not migrate or fly long distances. This makes them vulnerable to threats such as habitat loss and degradation, a warming climate, and invasive species. In Arizona, the majority of the owls’ range is now limited to the Altar Valley where Rancho de la Osa sits on its southern boundary.
The United States Fish and Wildlife Service, Arizona Game and Fish Department, Phoenix Zoo, and Wild at Heart Rescue have worked together since 2018 to breed owls in captivity to be released into the wild.
Rancho de la Osa is a part of the effort to help bolster the owl population in their native range. After the owls are transferred into the mesquite woodland aviaries, they are fed and watered every day by a third party. They are also remotely monitored by biologists through cameras placed in the aviaries to study their behavior. The owls remain in their acclimation pens for 10 days before release. Their whereabouts after that are monitored by tracking devices and call surveys done by an AZ Game and Fish Department biologist.
MAMMALS IN THE AREA
The Altar Valley is also home to many different species of mammals, large and small. Enjoy herds of pronghorn, mule deer and Coues whitetail deer dotted in the desert grasslands, and keep an eye out for evidence of some of the area’s big cats including mountain lions and bobcats.
JAVELINA
MOUNTAIN LION
JACKRABBIT
BOBCAT
PRONGHORN
MULE DEER
THE ELUSIVE JAGUAR
The jaguar is the largest cat species in the Americas. His presence is constant in portions of Mexico and southward into Argentina. Presently, the cat is rarely detected in the United States and is protected as an endangered species under the U.S. Endangered Species Act.
Over the past 50-plus years, only male jaguars have been detected in the U.S., averaging one to two individuals per decade. One of those males, dubbed Macho B, was first documented in the U.S. in 1996. He was treed by hound dogs getting exercise for future lion hunts in the Baboquivari mountain range, about 20 miles north of Rancho de la Osa. Macho B’s life was almost the exclusive focus of U.S. jaguar research over his 15-year life span. He was documented walking past the iconic saguaro cactus, drinking from a mesquite-rimmed cattle tank, and rolling in a dirt trail that Gila monsters and desert tortoise utilized, too.
As of 2024, there is one jaguar known to exist in the United States. In December 2023, the jaguar, now dubbed Cochise, was videotaped in a mountain range of southern Arizona. This cat was also photographed twice, in March and May of the same year, by remote cameras in Arizona's Huachuca Mountains, about 150 miles east of La Osa.
Coincidentally, the Huachuca Mountains were the location of a shipping container border wall ordered to be built in late 2022 by former Arizona Governor Ducey. The 2023 jaguar photos were taken after that version of a border wall was dismantled just a few months later. The container wall and the bollard style border wall south of La Osa are prime examples of what threaten jaguar presence and persistence in the United States – obstruction to movement.