Using Estimates

The Integrated Monitoring in Bird Conservation Regions (IMBCR) program collects breeding bird information each year in multiple states throughout the Rocky Mountains, Great Plains, and Intermountain West. Every year, occupancy and density estimates are calculated at a variety of spatial scales. This information is used in the following ways to inform avian conservation and management:

  1. Bird population estimates are compared in space. For example, we can compare stratum-level estimates to state and regional estimates to determine if local populations are faring better or worse than regional populations. We can also use abundance estimates to determine conservation stewardship for a management stratum within a state or BCR.
  2. Population estimates are used to inform management decisions about where to focus conservation efforts. Strata with large populations can be targeted for protection and strata with low populations can be prioritized for conservation action. Managers can also set a threshold to trigger a management action when populations reach a pre-determined level.
  3. Species detections and density estimates inform impact analyses for project-level planning. For example, a biologist can see what has been detected within a management stratum and could be impacted by a proposed project. The density estimates will provide an indication of the potential population impact for birds; multiply density by the project area (in km2) to estimate the number of individuals that could be impacted by the project. Then compare this number to the stratum-level abundance estimates for context and to see if the project is impacting a large proportion of the population.
  4. Annual estimates of density and occupancy are compared over time to determine if population changes are a result of population growth or decline and/or range expansion or contraction. If population densities of a species declined over time, but the occupancy rates remained constant, then the population change was due to declines in local abundance. In contrast, if both density and occupancy rates of a species declined, then population change was likely due to range contraction.
  5. Occupancy rates are multiplied by the land area in a region of interest to estimate the area occupied by a species. For example, if a stratum comprises 120,000 km2 and the occupancy estimate for Western Meadowlark is 0.57, managers can estimate that 68,400 km2 (120,000 km2 * 0.57) of habitat within that stratum is occupied by Western Meadowlarks. 
For more real-world examples of how population estimates are used, visit this spreadsheet to see past and current raw data requests, projects targeting specific management or conservation questions (overlay projects), additional analyses to address IMBCR partner needs, publications, reports, and tools.
2012 Rocky Mountain Observatory