Grassland Habitat Monitoring for Wintering Chestnut-collared Longspur

The Chestnut-collared Longspur (Calcarius ornatus; CCLO) is a grassland bird that winters in shortgrass prairies and desert grasslands of the South-Central and Southwest United States and the Chihuahuan Grasslands of North Central Mexico. This species feeds on native grass seeds in high-density flocks, uses cattle water tanks as its primary water source, and prefers areas recently burned, grazed, or mowed. 

Generally, grassland bird species’ populations have been declining since 1970 due to a decrease in suitable grassland habitats. Land use practices such as agricultural development, paired with competition from invasive grass species, such as Lehmann’s lovegrass (Eragrostis lehmanniana), are the largest drivers of grassland degradation. Specifically, trends show an 87% reduction in CCLO population since 1966, with 33% of this decline occurring between the years 2003 and 2015 ( Ashpole et al. 2023 ). As a result, CCLO is categorized as Vulnerable on the International Union for Conservation of Nature’s (IUCN) Red List, making them a high priority for surveying and monitoring to identify land management practices and conservation actions to support this vulnerable species.

For over ten years, the Tucson Audubon Society has collaborated with Audubon Southwest through the Important Bird Area (IBA) program to develop a protocol to survey two IBAs for CCLO: the San Rafael Grasslands IBA and the Las Cienegas National Conservation Area IBA. The collaboration leverages volunteer efforts and uses audio recordings from Autonomous Recording Units to survey CCLO population, preference in cattle water tank conditions, and the presence of Lehmann’s lovegrass. Data gathered can inform future management decisions that support healthy winter habitats for CCLO and inform our understanding of CCLO occupancy in the project area.