Cactus ferruginous pygmy owl’s fight for federal protection in Arizona

PHOENIX — The cactus ferruginous pygmy owl native to Arizona, one of North America’s smallest raptors, was unprotected by the federal government for nearly two decades entering last week.

The U.S. Fish and Wildlife Service, following multiple lawsuits, petitions, two 12-month findings and a 60-day public comment period, listed the owls as threatened, determining they are at risk of becoming endangered in all or a significant portion of its habitat.

This has been a long time coming in the eyes of conservation groups such as the Center for Biological Diversity, which has sued the federal government multiple times for the lack of protection.

“The fierce little cactus ferruginous pygmy owl needs our care and protection and after a long fight it finally got it,” Noah Greenwald, endangered species director at the Center for Biological Diversity, said in a press release. “If we lose this owl, we’ve lost the Sonoran Desert and so much more.”

FWS analyzed the bird’s territory in Arizona, northern Sonora, western Mexico, Texas and northeastern Mexico to determine its viability and existential threats.

Two primary dangers the cactus ferruginous pygmy owl were outlined: habitat loss and changing climate conditions.

The birds are important cogs atop the food chain and, as Greenwald put it, an indicator of the health of the ecosystem. Arizona has the lowest abundance of the pygmy owls of its historical range, with a population estimated in the low hundreds.

What is the cactus ferruginous pygmy owl?

The cactus ferruginous pygmy owl is a small, reddish brown bird with light streaks that measures less than seven inches long. They weigh less than three ounces and nest in the cavities of saguaros and other desert trees and scrubs. The owls hunt birds, insects, lizards, and small mammals, primarily at dusk and dawn.

The subspecies of the ferruginous pygmy owl range used to nearly reach Phoenix, as they were described as common or fairly common along the Gila and Salt rivers in central Arizona and the Santa Cruz River and Rillito Creek near Tucson, according to the FWS assessments report in 2021.

Attempts to find the owls along the Salt River since 1971 have gone unsuccessful, as current populations in the state are restricted from Organ Pipe Cactus National Monument in the west across the Tohono O’odham Nation to Altar Valley near Tucson in the east, according to Pima County.

The owls were listed under the Endangered Species Act in 1997, but the the Arizona distinct population segment was removed in 2006 after a court battle with developers, thus eliminating designated critical habitat.

The Center for Biological Diversity and Defenders of Wildlife quickly petitioned to protect the owls once again.

“Today’s action is a long overdue step in the right direction for this little owl that has been bereft of the protections of the Endangered Species Act for nearly two decades.” Bryan Bird, Defenders of Wildlife Southwest program director, said in a release. “Habitat loss, the border wall and climate change all present grave threats to this bird, and the listing recognizes this reality.” 

Pygmy owl threats

Habitats impacted

Arizona’s population growth rates expanded significantly since 2010, including in the historic habitat of these owls, according to the Federal Register.

The Maricopa-Pima-Pinal counties area of Arizona is expected to grow by as much as 132% between 2005 and 2050, creating rural-urban edge effects across thousands of acres of pygmy-owl habitat … If build-out occurs as expected, it will encompass a substantial portion of the current and historical distribution of the pygmy-owl in Arizona.

FWS concluded that as human populations increase, habitat loss and fragmentation will go up, removing connectivity from the remaining owl populations in the state. Border communities also continue to grow, and activity along the southern border creates another boundary.

The emergence of invasive species in owl habitat also adds to the pressure on the species, specifically buffelgrass. 

Buffelgrass is native to the eastern hemisphere and was planted in the U.S. for cattle to forage in the 1930s. It is adaptable to arid climate zones and can spread fires quickly, transforming desertscrub areas to savannahs unsuitable for pygmy owls.

Habitat loss and fragmentation will impact both the eastern and western populations of pygmy-owls through reduced size and number of suitable blocks of nesting habitat and nest cavity availability, loss and reduction of habitat connectivity and the ability of pygmy-owls to move across the landscape to provide demographic and genetic rescue, loss and reduction of prey availability, and the increase of potential threats related to predation, pesticides, and human disturbance.

Climate change

FWS has evaluated climate models and projections, National Climate Assessments, Normalized Difference Vegetation Index datasets and examinations to determine the owl’s vulnerability to climate change.

Rising temperatures, increased drought and more extreme weather events would impact the owl in the following ways: reduced vegetation cover, decreased prey, increased predation, fewer nest sites available and lower survivability rates.

The population of saguaros has declined with long-term climate cycles of frost and drought, impacting critical nesting ground for the owls.

Deep inside a saguaro cactus, these ferruginous pygmy owl chicks are safe from the heat of the desert sun 🌵 ☀️ #MEXICO pic.twitter.com/zvwNlBHys8

— BBC Earth (@BBCEarth) May 21, 2017

Fight for protection

Conservation groups petitioned in 1992 for the owls to get listed un the Endangered Species Act, which came to fruition on March 10, 1997.

FWS established critical habitat in 1999, leading to a 2001 lawsuit in the District Court of Arizona challenging the validity of the listing and habitat protection. The United States Court of Appeals for the Ninth Circuit concluded that FWS acted “arbitrarily” in 2003, and FWS reassessed, resulting in the owl’s protections getting lifted.

The Center for Biological Diversity and Defenders of Wildlife petitioned in 2007 to re-list the birds and after a 12-month finding, FWS deemed in the Federal Register the protection was not warranted in “all or a significant portion” of its range.

The two organizations sued in 2012, with Defenders of Wildlife attorney Jason Rylander saying at the time, “The policy will wrongly delay protection until species are in absolutely dire straits and on the very brink of extinction, making recovery a difficult uphill slog.”

Following the lawsuit and petitions, FWS developed a new 12-month finding under a court settlement, published in 2021.

A lot changed in a decade, highlighted by climate impacts to pygmy-owl habitats, land uses and additional genetic sampling. The birds continued to show high resiliency in its western Mexican habitat, which was not the case in Arizona.

Surveying efforts in 2020 and 2021 concluded pygmy-owls were no longer seen “reliably” in Organ Pipe Cactus National Monument. Abundance was higher in Altar Valley than in 2011, which FWS concluded is likely traced to increases in surveying and monitoring under Pima County’s Multi-Species Conservation Plan.

Meanwhile, there are an estimated tens of thousands of pygmy-owls in western Mexico due to healthy vegetation cover, although populations in the county have seen “notable” declines.

Listing the species as threatened creates public awareness and opens the door for conservation planning from federal, state, local and tribal agencies.

“Collaborative conservation efforts with a diversity of cooperators in Arizona, Texas and Mexico have further protected pygmy-owl habitat through habitat acquisition and protection in Arizona and have greatly enhanced our understanding of the species,” FWS Southwest Regional Director Amy Lueders said in a release. 

FWS will announce a separate proposal to designate critical habitat.

Pima County’s Multi-species Conservation Plan and the Altar Valley Watershed Plan will contribute to the protection and enhancement of the pygmy owl’s habitats.

“It is our hope that in the 17 years that have passed, the federal government and nonprofit organizations will finally have the required tools to help save this unique owl,” Bird said.