In Spirit of Thrashers: Thrasher Conservation in Avi Kwa Ame

By Morrigan DeVito

LeConte’s and Bendire’s Thrashers are two of Southern Nevada’s fastest declining bird species. Will the proposed Avi Kwa Ame National Monument be enough to protect them?

On Nov. 30 2022, President Biden announced his intention to designate Avi Kwa Ame as Nevada’s fourth national monument, honoring indigenous tribes and protecting 450,000 acres of biologically and culturally significant lands in Southern NV. The proposed designation is welcome news in the bird conservation world, where two threatened species, the LeConte’s Thrasher and Bendire’s Thrasher, depend on the Joshua tree woodlands and creosote-bursage habitat of the proposed Avi Kwa Ame National Monument.

What are thrashers?

Thrashers are a type of passerine that get their name from the way they forcefully swish their bill back and forth in leaf litter and dirt, thrashing around to find food. Both LeConte’s and Bendire’s thrashers are generalists, meaning they eat a variety of foods. They will glean insects off the ground and seeds from mesquite trees and other desert plants. 

In the mimid family like mockingbirds, thrashers have a similar body shape with long tails, strong legs, and rounded, short wings. They prefer to be on the ground, which makes them hard to find in the desert because they run instead of flying away. The bright, golden eye of a Bendire’s Thrasher is reminiscent of a Northern Mockingbird’s inquisitive gaze, but the LeConte’s Thrasher has a much darker eye and a longer, decurved bill. Like mockingbirds, thrashers have complex songs and may mimic other birds.

Partners of RRAS, the Great Basin Bird Observatory (GBBO) conducts thrasher surveys across Nevada. Wildlife biologist Dawn Fletcher is described as their “resident thrasher expert” and came to the thrasher world after receiving her master’s degree from UNLV in 2009. Her graduate research was steered by GBBO’s executive director, Elisabeth Ammon, and focused on habitat preferences of LeConte’s, Bendire’s and Crissal Thrashers.

“I am so grateful Elisabeth brought the desert thrasher species to my attention,” Fletcher says. “The thrashers quickly captured my heart, especially the LeConte’s Thrasher. I love their curious nature, inquisitive call, the fact that they run through the desert popping up to observe the environment, and that you need to work hard to find them. It always makes me happy to heartheir sweet suuweeeep call ringing through the desert.”

What is the conservation status of Bendire’s and LeConte’s Thrashers?

According to the 2022 State of the Birds report, which compiles data on changes in bird populations across the United States over the last five decades, Leconte’s and Bendire’s Thrashers have experienced significant declines. As two tipping point species, they are on the U.S Fish and Wildlife Service’s “Birds of Conservation Concern” list, meaning that without conservation action, they are at risk of being listed on the Endangered Species Act. They are also listed in the Nevada Department of Wildlife’s 2012 Wildlife Action Plan due to concerns over the stability of Mojave Desert shrub habitat.

Bendire’s and LeConte’s Thrashers have lost at least half of their total populations in the last 50 years and are monitored by GBBO and Partners in Flight as Red Watch List birds because they are at risk of population collapse. According to the North American Breeding Bird Survey, Bendire’s Thrasher populations have declined 86% and LeConte’s Thrashers have declined 68% between 1968 and 2015.

One challenge in thrasher conservation is that these birds are difficult to monitor in the large expanses of desert shrubland and Joshua tree woodland. Their populations are scattered and their feathers are excellently camouflaged gray-brown and sandy-brown like desert stones as they forage low to the ground. They also eat ephemeral foods, which means they go to different nesting spots every year that researchers have to find anew.

The State of the Birds report classifies Bendire’s and LeConte’s Thrashers as “aridland birds”, a Western region that encompasses the entire state of Nevada. Aridland birds face threats from drought, invasive species, development, and energy extraction in their habitat, among other things.

Fletcher describes, “I think the biggest threat to both these species is solar development. It would be wonderful if land managers could try to do pre and post monitoring surveys in areas proposed for solar projects [...] Little is known about how to adequately address the urgent conservation needs of these species.”

Referring back to their 2011 report, which found that 80% of publicly owned aridlands are vulnerable to activities that could potentially degrade bird habitat, the State of the Birds notes that public land management plans and public land advocacy are imperative to protecting aridland bird habitat. Right now, only some areas in the proposed Avi Kwa Ame National Monument are protected, making habitat fragmented and vulnerable to large-scale development.

Bendire’s and LeConte’s Thrashers in Avi Kwa Ame

In a parched landscape west of the Colorado River and Lake Mead National Recreation Area, the proposed 450,000 acres of Avi Kwa Ame National Monument would ensure that populations of LeConte’s and Bendire’s Thrashers, as well as other wildlife, would be connected to the Mojave National Preserve in CA. Without this ecological connectivity, wildlife populations become fragmented and genetically isolated, unable to cross human development. West of Searchlight, the Wee Thump Joshua Tree Wilderness and Walking Box Ranch are two places where Bendire’s and LeConte’s Thrashers live.

Ned Bohman, GBBO’s outreach coordinator, states, “There are few areas of such high quality Joshua tree forest as the Wee Thump wilderness area. The proposed monument would connect these to the 1,542,776 acre Mojave National Preserve, creating a huge area of protected high quality habitat.”

Despite their similar range, Bendire’s and LeConte’s thrashers utilize different habitats. Bendire’s Thrashers are migratory in Nevada and use the Northern portion of their range to breed in Joshua tree woodland, often arriving by late March. Although they prefer to nest in Joshua trees, their nests have been found in thorny thickets of teddy bear cholla, catclaw acacia, and Mojave yucca, all of which are prevalent in the proposed national monument.

Unlike Bendire’s Thrashers, LeConte’s Thrashers are year-round residents of Nevada. While they do use Joshua tree habitat and overlap with Bendire’s Thrashers, they prefer lower elevation Joshua tree woodlands full of silver cholla, which provides them with the best nesting substrate. They also nest in saltbush shrublands and creosote-bursage shrublands. Avi Kwa Ame is full of sandy washes with creosote-bursage plant communities, prime habitat for these thrashers.

Bohman explains, “[...] the fact that they are resident species means that the proposed monument has the potential to protect their entire life cycle. [...] Protecting a large area of habitat used by the species has the potential to affect a large number of birds, because we know that they do not have large territories.”

What current field work is done on thrashers?

GBBO is part of the Desert Thrasher Working Group (DTWG), a network of state, federal, and non-governmental organizations whose goal is to fill in the thrasher knowledge gaps to better inform conservation action for land management practices. They focus on raising awareness, promoting research, and enhancing monitoring strategies of LeConte’s and Bendire’s Thrashers, along with Loggerhead Shrikes.

As part of the DTWG since its founding in 2011, Fletcher helped establish a thrasher survey protocol to standardize how biologists survey LeConte’s and Bendire’s Thrashers. GBBO and the DTWG have continued this survey work since 2017, even spreading the survey protocol to Mexico in 2020. In order to tell the story of LeConte’s and Bendire’s thrashers, data has to be collected and standardized between agencies.

“The group designed standardized inventory, monitoring, and centralized data management protocols that address basic needs for driving conservation of the species forward,” Fletcher explains. Then, they examined all the data from historic locations and generated the first spatial habitat suitability models for the two species. This allowed the states of NV, AZ, CA, NM, and UT to generate an updated distribution map and conduct vegetation analysis to describe the breeding habitats of LeConte’s and Bendire’s Thrashers.

In other words, researchers can now see exactly which plants, like the Joshua tree and silver cholla, these thrashers rely on. Knowing the plants helps inform management practices, especially when advocating for public lands like Avi Kwa Ame. Without knowing what plants these birds use, researchers don’t know where to look for them or what habitats have the highest priority needs. Now, biologists know that protecting Joshua tree woodlands and creosote-bursage shrublands in Avi Kwa Ame is imperative to the breeding successes of Bendire’s and LeConte’s thrashers.

RRAS Statement For Avi Kwa Ame

RRAS is part of the Honor Avi Kwa Ame Coalition, a team of local tribes, Searchlight, Boulder City and Laughlin residents, the Nevada Legislature, conservation groups, recreation groups, and others working to establish the Avi Kwa Ame National Monument.

On Nov. 17, the Bureau of Land Management held a public hearing in Laughlin, NV, to discuss the proposed 450,000-acre Avi Kwa Ame as Nevada’s next national monument. RRAS was one of 300 supporters at the hearing. Joined by partners from the Nevada Conservation League, Sierra Club, and others, members of RRAS came to support the Fort Mojave Indian Tribe and other tribal leaders.

Alex Harper, RRAS Education and Outreach Chair, issued a statement on behalf of RRAS about how birds, particularly Bendire’s and LeConte’s Thrashers, use the Joshua tree and creosote-bursage habitat. He described how short-sighted human activities have led to the decline of these bird populations, and urged the Biden administration, “Let’s begin thinking in the long-term about how we can use the land which brings us together.”

President Biden’s announcement that he intends to make Avi Kwa Ame Nevada’s next national monument is a cause for celebration in itself. The 2022 State of the Birds states that co-creating solutions with indigenous communities and advocating for public lands is essential to bird conservation, especially aridland birds like these thrashers. Avi Kwa Ame shows just how powerful activism for public lands is when environmental justice is at the forefront.

Alongside the Avi Kwa Ame Coalition, RRAS urges President Biden to honor the original proposed boundaries of Avi Kwa Ame in accordance with the tribal nations who have organized this movement. This ensures the greatest swathe of ecologically vital habitat for thrashers and other bird species, and furthermore honors the spiritual significance of Avi Kwa Ame to tribal nations. People can add their name to the official Avi Kwa Ame petition to advocate for Avi Kwa Ame’s protection.

For Fletcher, the Wee Thump Joshua Tree Wilderness holds a special place in her heart as a place to connect with the thrashers that have shaped her life. “I have often in the past heard that the LeConte’s Thrasher lives in the most desolate desert environment,” she says. “[...] but of course, to anyone who has spent any time out in the desert, they know that isn’t true. The desert is one of the most remarkable habitats, and Wee Thump wilderness is one of my most favorite places in Southern Nevada. I am so happy that there is a chance it will be preserved for posterity.”

Bendire's Thrasher: Bobby Wilcox

LeConte's Thrasher: Great Basin Bird Observatory

Saltbush habitat: Michelle Tobin