Filling in the Gaps: Southwestern Willow Flycatcher and Other Birds Surveyed at Carlsbad Caverns National Park

By Summer Boulais, I&M Science Communicator

November, 2024
Carlsbad Caverns National Park (NP) in New Mexico is known for its underground beauty, but visitors who stay above ground are exposed to the musical talents of the birds above! A hidden gem in the park is Rattlesnake Springs which is home to an abundance of biodiversity. This desert oasis provides a lush habitat for a variety of bird species, including the southwestern willow flycatcher (Empidonax traillii extimus).

Why Do These Birds Matter?

The southwestern willow flycatcher is a small bird of less than 15 cm that preys on insects, often catching them in mid-air. They help maintain a balanced ecosystem by keeping insect populations in check. Southwestern willow flycatchers occupy habitats in riparian zones— or land that occurs along bodies of water, such as Rattlesnake Springs. One of the biggest threats to this endangered species is the loss of native riparian habitats, so it is critical to preserve areas like Rattlesnake Springs. Visitors can help by staying on designated paths to avoid the creation of social trails.

Riparian habitats can serve as natural water filters by trapping pollutants before they can enter larger bodies of water.

NPS

Surveying the Springs

A gap in knowledge was evident at Carlsbad Caverns NP as staff were uncertain about the presence of southwestern willow flycatchers and other birds in Rattlesnake Springs. Park staff teamed up with the Tucson Audubon Society and the National Park Service’s Inventory and Monitoring Division to conduct an intensive survey. This survey included identifying the southwestern willow flycatcher’s potential breeding territories and foraging habitats. In addition, surveyors aimed to record all bird species present in the area.

Make it Count

Researchers conducted technical surveys called “point counts” where bird species and the number of birds are recorded at set locations for a certain duration of time. This common standardized survey technique requires advanced training to identify bird species by sight and sound. Surveyors recorded all birds at selected point counts over a 10-minute time frame in Rattlesnake Springs, while also documenting incidental sightings between points. Two routes were selected to cover previously known breeding and foraging habitat of the southwestern willow flycatchers.

Rattlesnake Springs is home to a large grove of cottonwood trees.

NPS

What’d They Find?

A total of three southwestern willow flycatchers, one pair and a single, were detected during the survey. A total of 62 different bird species were recorded during the survey period, including the threatened Bell’s vireo (Vireo bellii). The survey results show the rich biodiversity of Rattlesnake Springs, which provides birds and other species access to water in the middle of the desert.

Conserving Carlsbad

This survey was incredibly useful for park managers as it helped them adjust management activities to protect southwestern willow flycatchers. For example, noise limits and timing restrictions on mowing have been set near nesting and foraging habitat. Discovering the presence of southwestern willow flycatchers and other species helps park managers make decisions that best maintain wildlife communities and healthy habitats. Make sure to always be mindful and follow park regulations when visiting the park to help conserve vital habitats for these birds and other wildlife. It is important to maintain the biodiversity and beauty of Carlsbad Caverns NP, both below and above ground!