Horned Lark (Eremophila alpestris) Conservation Status Review
Review Date = 12/22/2011
ScoreH - >1,000,000 individuals
CommentRecent Integrated Monitoring in Bird Conservation Regions (IMBCR) Program data for 2010 estimates the statewide population at 11,120,885 +/- SD of 1,668,132.
ScoreG - 200,000-2,500,000 km squared (about 80,000-1,000,000 square miles)
Comment380,531 square kilometers based on Natural Heritage Program range maps that appear on the Montana Field Guide
Area of Occupancy
ScoreU - Unknown
ScoreE - Relatively Stable (±25% change)
CommentAlthough grassland covertypes have been drastically reduced in Montana since European arrival, the species still uses agricultural lands so populations have likely been stable within +/- 25% since European arrival.
ScoreD - Declining. Decline of 10-30% in population, range, area occupied, and/or number or condition of occurrences
CommentBreeding Bird Survey data for Montana is of high credibility and shows a significant negative trend of -1.4% per year or a 13% decrease per decade. Most surrounding states and provinces with suitable habitat show similar levels of decline (Idaho is the exception).
ScoreF - Widespread, low-severity threat. Threat is of low severity but affects (or would affect) most or a significant portion of the population or area.
CommentAgricultural impacts such as pesticide and herbicide use and collisions with vehicles and wind turbines are likely the greatest threats to the species.
SeverityLow - Low but nontrivial reduction of species population or reversible degradation or reduction of habitat in area affected, with recovery expected in 10-50 years.
CommentSpecies should recover quickly if threats are removed.
ScopeModerate - 20-60% of total population or area affected
CommentLikely that greater than 20% of population is affected by a combination of agriculture and/or collisions.
ImmediacyModerate - Threat is likely to be operational within 2-5 years.
ScoreC - Not Intrinsically Vulnerable. Species matures quickly, reproduces frequently, and/or has high fecundity such that populations recover quickly (< 5 years or 2 generations) from decreases in abundance; or species has high dispersal capability such that extirpated populations soon become reestablished through natural recolonization (unaided by humans).
CommentNot Intrinsically Vulnerable. Species matures quickly, reproduces frequently, and/or has a high fecundity such that populations recover quickly (< 5 years or 2 generations) from decreases in abundance. Species has good dispersal capabilities such that extirpated populations generally become reestablished through natural recolonization.
ScoreC - Moderate. Generalist. Broad-scale or diverse (general) habitat(s) or other abiotic and/or biotic factors are used or required by the species but some key requirements are scarce in the generalized range of the species within the area of interest.
CommentModerate Generalist. Use a variety of natural and human altered landscapes with low cover grassland vegetation.