The Lark Bunting (Calamospiza melanocorys) is a medium-sized songbird found in the grasslands and prairies of western North America. Once a common sight across the Great Plains, this distinctive black, white, and gray bird has experienced significant population declines over the last few decades. Many birders and conservationists now wonder: is the Lark Bunting rare?
To answer this question, we need to look at the Lark Bunting’s historical population trends, current conservation status, geographic range, and potential threats. While the Lark Bunting is still found across much of its original habitat, both its range and total numbers have shrunk considerably from historical levels. Factors like habitat loss, climate change, and pesticide use have all contributed to the species’ worrisome declines. While the Lark Bunting is not yet considered globally threatened, local populations in many areas are now small and isolated. Continued conservation action will be needed to protect this iconic grassland bird.
Historical Population and Distribution
The Lark Bunting was once one of the most abundant breeding birds on the Great Plains. Early explorers in the 1800s described the species in spectacular superlatives, with famed ornithologist John James Audubon calling them “so numerous that the attention of the voyager is arrested by the novel appearance which they present.” Their flocks were said to blacken the skies and meadows during migration and nesting. While we lack precise population estimates from this period, the Lark Bunting’s numbers certainly reached into the tens of millions or even hundreds of millions of birds. They bred across almost the entire Great Plains region, from Alberta and Saskatchewan down through Texas, and migrated as far south as central Mexico for the winter. The massive flocks and huge breeding range reflected a thriving, common species.
Starting in the late 1800s, however, the Lark Bunting’s population underwent a steep decline as its favored shortgrass prairie habitat began disappearing. The great herds of bison that had shaped these grasslands were destroyed by overhunting, replaced by livestock grazing that altered plant composition. Meanwhile, large portions of the prairie were converted to cropland. By the early 20th century, naturalist Frank M. Chapman noted that the once-common Lark Bunting had become “decidedly rare east of the Missouri river.” The population crash continued through the mid 1900s, eventually reducing the Lark Bunting’s numbers to a small fraction of their historical abundance. One estimate suggests the population may have fallen from over 200 million to around 13 million birds during the 20th century. While still relatively common in parts of the high plains, the Lark Bunting became yet another victim of habitat loss and agricultural expansion.
Current Population and Status
Today, the Lark Bunting remains a relatively common breeder in portions of its original range, including Colorado, Wyoming, Montana, and the western Dakotas. However, both its breeding and wintering ranges have contracted significantly from historical times. The species no longer regularly nests in significant portions of eastern Nebraska, Kansas, Oklahoma, or Texas. The winter range has retracted northward as well, with few Lark Buntings now reaching northern Mexico. Lark Buntings have essentially disappeared as a breeding species east of the Missouri River and from much of the southern Great Plains.
The most recent population estimate for Lark Buntings comes from the Partners in Flight Landbird Conservation Plan published in 2019. This plan estimates the species’ total population at around 13 million adults. For comparison, the population of the widespread Red-winged Blackbird is estimated at over 200 million. While 13 million individuals may still sound abundant, it represents a huge decline from historical numbers. It places the Lark Bunting far below most other common grassland songbirds in abundance.
Due to these substantial declines, the Lark Bunting is ranked as a Species of Conservation Concern at both state and federal levels across much of its current range. However, most authority groups stop short of listing it as officially Threatened. The IUCN considers the Lark Bunting to be a Species of Least Concern globally, though it notes the species’ worrisome disappearance from many regional breeding populations. The Lark Bunting is considered endangered, threatened, or of conservation concern in several states including California, Washington, Montana, Minnesota, and Massachusetts. But in its core Great Plains breeding range, it has not yet met criteria for being Threatened. So while the Lark Bunting is much rarer than it once was, most groups do not consider it at immediate risk of extinction. However, its vulnerable condition means it warrants continued monitoring and habitat protection.
Breeding and Wintering Range
The Lark Bunting now breeds across much of the western Great Plains and intermountain west. The core of its breeding range includes:
- Southern Alberta and Saskatchewan
- Montana and western North and South Dakota
- Most of Wyoming
- Colorado
- Western Nebraska and Kansas
- Eastern New Mexico and northwest Texas
Smaller breeding populations occur in central California, eastern Washington, western Minnesota, and occasionally further east. The winter range has contracted mainly to:
- Southeastern Arizona
- Southern and central Texas
- Northern Mexico
So while still found over a wide area, the species’ breeding and wintering distribution is now significantly smaller than in historical times. For example, Breeding Bird Survey data shows that Lark Buntings have declined by over 3% annually in Texas since the 1960s, representing a staggering 90% overall decline in the Lone Star State. The range retractions reflect ongoing habitat issues across both its nesting and wintering grounds.
Major Threats
What caused the Lark Bunting’s precipitous decline over the last 150 years? And what threats continue to affect the species today? A number of interrelated factors are responsible:
Habitat Loss on the Great Plains
Lark Buntings rely on open grasslands with relatively sparse vegetation, especially mixed-grass and shortgrass prairie. However, the native prairie has been extensively converted to cropland over the past century. Although Grasslands National Park and other reserves protect some habitat, ecosystems scientists estimate over 70% of the original mixed-grass prairie has been lost. This has reduced nesting habitat for the Lark Bunting while also fragmenting the remaining prairie into smaller, more isolated patches. Intensive livestock grazing and altered fire regimes have also degraded prairie quality in some areas.
Habitat Loss on the Wintering Grounds
In winter, Lark Buntings rely on open grasslands and agricultural fields across the southwestern U.S. and northern Mexico. Here, too, development and agricultural intensification have led to habitat loss. For example, over 95% of native grasslands in California have been lost over the past 200 years. And many wintering Lark Buntings are now dependent on private cattle ranches, which are being subdivided for urban or commercial use.
Climate Change
Climate change may significantly impact Lark Buntings by altering prairie habitat and drying out nesting sites. The potential for more frequent droughts could reduce food supplies while increasing risks of nest failure or abandonment. Shifting seasons may also cause timing mismatches between migration and optimal breeding conditions. Modeling suggests the Lark Bunting’s already diminished range could contract even further in a warmer future.
Pesticides
Lark Buntings forage extensively on insects, especially grasshoppers. However, the widespread use of pesticides and insecticides on croplands has reduced food availability while also exposing the birds to harmful chemicals. Neonicotinoid insecticides in particular have been implicated in songbird declines across North America.
Other Factors
Collisions with vehicles and infrastructure pose an understudied threat to Lark Buntings during migration. Increasing frequency and intensity of storms, combined with habitat fragmentation, may also limit population resilience. And lack of awareness among landowners means conservation action is sometimes limited. Taken together, these multiple issues paint an uncertain future for the Lark Bunting.
Conservation Actions and Research Needs
Habitat Protection and Restoration
Protecting intact prairie habitat – both public and private lands – will be key for Lark Bunting conservation. Further habitat losses and fragmentation must be minimized. Restoring croplands or degraded areas to native vegetation may aid recovery. Financial incentives can encourage ranchers to manage their properties in bunting-friendly ways. Government conservation programs should prioritize habitat projects in Lark Bunting range.
Regulation of Pesticide Use
Tighter regulations around neonicotinoids and similar pesticides could help reduce poisoning risks to the Lark Bunting. Tax incentives might encourage farmers to minimize insecticide applications during the breeding season when possible. Integrated pest management approaches can maintain crop yields while reducing environmental impacts.
Expanded Breeding Bird Surveys
Better annual monitoring of Lark Bunting populations is needed, especially in under-surveyed portions of their range such as tribal lands or northern Mexico. Standardized surveys should track the species’ shifting distribution so conservation priorities can be adjusted.
Migration and Wintering Research
We lack information on migration routes, stopover sites, and wintering grounds for particular breeding populations. Banding, telemetry, and population genetics studies could fill these knowledge gaps and help pinpoint areas in greatest need of protection.
Climate Change Modeling
Studies that model the impacts of climate change on Lark Bunting breeding and wintering grounds could help guide habitat management under future conditions. Identifying likely future strongholds may aid conservation planning.
Conclusion
The Lark Bunting was once among the most abundant species in North America but has suffered substantial population declines since the 19th century. While still locally common, habitat loss and other threats have reduced the Lark Bunting’s overall numbers by over 90% and significantly contracted its breeding and wintering range. The species is now rare or absent across much of its historic distribution. Most authorities consider the Lark Bunting a species of conservation concern warranting continued monitoring and habitat protection. However, it is not currently considered globally threatened with extinction. Ongoing conservation action including private land partnerships, pesticide regulation, and habitat restoration will help ensure the iconic Lark Bunting remains a part of the prairie ecosystem into the future. Though not yet endangered, the Lark Bunting serves as an important indicator of our changing grassland landscapes.