How to Access the Information

To view interactive maps showing survey and detection locations, species counts, as well as density, occupancy, and trend estimates by stratum, click the Explore the Data tab at the top of the page.

Selecting Filters

We designed the Rocky Mountain Avian Data Center (RMADC) to provide information for specific questions, and therefore, it works best when users select multiple filters for a query.

Tip: Look at the annual IMBCR field season report to determine the Stratum or Superstratum relevant to you. Under the Results section, click on the relevant agency or geographic region on the left sidebar. Then use the “On this page” menu on the right side of the page to choose a management unit of interest. The relevant Stratum or Superstratum will be listed in a callout block in the reported results for that unit.

Geographic filters

Bird Conservation Region: Selecting this filter will provide you with results for all strata and superstrata within a particular Bird Conservation Region.

State: Selecting this filter will provide you with results for all strata and superstrata within a particular state.

Land Management Agency: This filter will allow you to select results for All Other Lands, Colorado State Land Board, The Nature Conservancy (TNC), US Bureau of Indian Affairs (BIA), US Bureau of Land Management (BLM), US Department of Defense (DOD), US Fish and Wildlife Service (USFWS), US Forest Service (USFS), or National Park Service (NPS).

Stratum: This filter allows you to select results for a geographic or management unit. Strata refer to areas of interest for funding partners or the areas for which we are estimaing bird desnity, occupancy, and trend. A National Forest or a BLM field office are common strata. In the Stratum search box, type in the name of your management unit or scroll down in the pop-up box to find your stratum (they are organized alphabetically by state. You can view an interective StoryMap of strata locations here.

Superstratum: This filter allows you to select results for states or regions containing multiple strata that were analyzed jointly (e.g., the entire state of Colorado which contains 30 individual strata). Please note, some management units represent superstrata if they have been stratified into smaller areas based on elevation, BCR/state boundary, or other features relevant for management. For example, the White River National Forest in Colorado is a superstratum because it contains 3 individual strata representing low, medium, and high elevation zones within the Forest.

Other filters

Baseline (IMBCR) or Overlay (GRTS): “Baseline” surveys are standard IMBCR surveys which contribute to statewide and regional estimates every year. These surveys are drawn from a spatially balanced random sample of a given geographic extent (e.g. a National Forest or BLM Field Office). These surveys are designed to monitor broadly across many species and habitat types. “Overlay” surveys are projects designed to answer a specific question, or monitor a specific subset of species or habitats. These surveys may be stratified by elevation, soil type, management or project boundaries, disturbance, etc. Some examples include projects designed to assess bird response to varying levels of impacts, such as human recreation on heavily used trails, oil & gas infrastructure, and grassland reseeding. You can read a short summary of each overlay project on this Google Sheet.

Species: This filter allows you to select results for an individual or multiple species.

Year: This filter allows you to select results for a particular year(s).

Viewing Maps and Counts (Map Tab)

What is displayed

The map displays all survey locations corresponding to your set of filters. If you have filtered by species, black circles represent survey locations where that species was not detected and pink circles represent survey locations where that species was detected.

By default, the zoom capability on the map is restricted to protect the privacy of private landowners. Funding and/or implementation partners wishing for precise location information should email Jennifer Timmer. Non-IMBCR partners should complete this Data Request Form.

The table below the map displays a count of the number of individuals detected on each individual sampling unit within a stratum, along with the survey date.

Adding map layers

Selecting a Bird Conservation Region or a Stratum in the filter boxes will display the boundary for that geographic extent.

Viewing Density/Occupancy/Trend Results (Density, Occupancy, Trend Estimates Tabs)

You may view the density, occupancy, or trend estimates tables for all appropriate strata, based on your filter selection, for which we have results, by clicking on the tabs labeled “Density”, “Occupancy”, or “Trend Estimates”.

The density tables display stratum, species, year, number of birds estimated per km² (Density), percent coefficient of variation (% CV), the lower 95% credible interval (Lower CI), the upper 95% credible interval (Upper CI), and the number of independent detections used in analyses (Detections).

The occupancy tables display stratum, species, year, Occupancy (proportion of plots of “plot area” expected to be occupied by the species in the stratum), the number of surveyed points on which the species was detected in the stratum (Detections), the percent coefficient of variation (% CV), the 95% credible interval (95% CI), and plot area (area in km2 that is determined by the distance at which we truncate detections).

The trend tables display stratum, species, the median trend estimate based on density (Density trend), confidence in the direction of the trend estimate based on density (Density f), the 95% credible interval for the trend estimate based on density (Density 95% CI), the median trend estimate based on occupancy (Occupancy trend), confidence in the direction of the trend estimate based on occupancy (Occupancy f), and the 95% credible interval for the trend estimate based on occupancy (Occupancy 95% CI).

Superstratum and Stratum Estimates

Density, occupancy, and trend estimates will always be displayed by individual strata in the top table and by superstrata in the bottom table. If, for example, you use the “Stratum” filter to select an individual management unit, estimates for all relevant superstrata will be included in the table below for regional context. If, for example, you use the “Superstratum” filter to select a region or state, estimates for all individual strata contained within that superstratum will be included in the top table.

Downloading the Information

You may click the Download button below each table to download species counts or density/occupancy/trend estimates by strata as a CSV file.

Viewing the Charts (Density and Occupancy Only)

When viewing the occupancy and density charts, the occupancy or density estimate for each year is indicated with a circle, and the error bars represent the 95% credible interval.

How to Interpret the Results

Density

Density is the number of birds per square kilometer within a stratum. Densities tend to reflect local management actions or habitat conditions and thus, are more likely to change year to year.

Occupancy

Occupancy is the probability that a species is present at each survey within the stratum. You can also think of occupancy as the proportion of surveyed points occupied by the species within a stratum. You can multiply the occupancy estimate by the “stratum area” to determine the area occupied by a species within a stratum.

Trend

We report trend as the percent population change per year based on all years a stratum was surveyed. We estimate population change based on both the density and occupancy estimates. Declining population trends are highlighted in red, while increasing population trends are highlighted in red.

How to Determine Robust Estimates

Density and Occupancy

The coefficient of variation (CV) is an indicator of reliability for density and occupancy estimates. We classify density and occupancy estimates as robust if their CV is < 50%, which is highlighted in yellow in the tables.

Trend

The f value is the probability that the population trend is in the direction (i.e. positive or negative) of the reported percent change per year. You can think of it as our confidence that a population is truly increasing or decreasing within a stratum. For example, an f value of 0.98 means we are 98% certain the population is increasing or decreasing within the stratum. We classify trend estimates as robust if they have an f value > 0.9, which are highlighted in light yellow. For partners that wish to use a more stringent cutoff for even higher confidence, we also highlight f values > 0.975 in gold.

We also report the 95% credible intervals as a tool to determine if a trend estimate is supported. Credible intervals (95% CI) are the upper and lower bounds containing the true population trend with 95% probability. 95% CIs which do not overlap zero are equivalent to f > 0.975. Note that trend estimates with an f value between 0.9-0.975, although robust, will have 95% CIs that overlap 0. This is because f > 0.9 is equivalent an 80% CI that does not overlap 0.

Stable populations have a trend estimate of approximately 0, which means the population isn’t increasing or decreasing each year. Stable populations will also have a narrow credible interval centered around 0 (e.g., -0.02-0.03).