Williamson's Sapsucker (Sphyrapicus thyroideus) Conservation Status Review
Review Date = 01/21/2009
Population Size
ScoreU - Unknown
CommentUnknown.
Range Extent
ScoreF - 20,000-200,000 km squared (about 8,000-80,000 square miles)
Comment126437 square kilometers based on Natural Heritage Program range maps
Area of Occupancy
ScoreG - 2,000-20,000 km squared (500,000-5,000,000 acres)
Comment4169 square kilometers based on GAP predicted model.
Long-term Trend
ScoreE - Relatively Stable (±25% change)
CommentMature conifer forests and aspen stands stable within +/- 25% since European arrival.
Short-term Trend
ScoreE - Stable. Population, range, area occupied, and/or number or condition of occurrences unchanged or remaining within ±10% fluctuation
CommentBreeding Bird Survey (BBS) is of low credibility in Montana and shows a 16% increase per year since 1980 which is a 441 percent increase over a 10 year time period. All surrounding states and provinces have low credibility but are either stable or increasing in trend. The Landbird Monitoring Program detected them at a higher rate in harvested forest types.
Threats
ScoreG - Slightly threatened. Threats, while recognizable, are of low severity, or affecting only a small portion of the population or area.
CommentNo major threat identified, but decline in conifer forest due to fire, beetle kill, and selected timber harvest or thinning probably represent a threat to some extent. Need to have groups of large snags and sap trees intact on the landscape.
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 seems to rely on a mix of habitat resulting from some level of disturbance
ScopeLow - 5-20% of total population or area affected
CommentSpecies seems to rely on a mix of habitat resulting from some level of disturbance
ImmediacyLow - Threat is likely to be operational within 5-20 years.
CommentNo immediate threats identified
Intrinsic Vulnerability
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).
Environmental Specificity
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.
CommentUses a broad variety of disturbed conifer and mixed conifer forests.