TABLE OF CONTENTS
- Select a species
- Select a time period
- Zoom and pan
- Draw a polygon
- Get Summary Statistics
- Edit a polygon
- Delete a polygon
- Change the week or species
- Export the data
- Basemap legend
- Options and Settings
Select a species
Select a shorebird species from the drop-down menu in the upper left of the screen.
Select a time period
Choose any week of the year from the drop-down menu in the upper left of the screen or click the arrows to advance by week.
Zoom and pan
Use the zoom in and out buttons in the upper left to zoom to a region. To move around on the map, click on the map and use the hand to pan to the desired location. Automatically zoom to a species full range by clicking ‘Full species range’ in the right panel.
Draw a polygon
To get summary statistics for a specific region, begin by drawing a polygon on the map. Enable draw mode by clicking the square button in the top-left corner of the map or click the "Draw custom polygon on map" button in the right-side panel.
Draw mode is active when the crosshairs cursor is visible on the map:
To draw a polygon, start by clicking on the map, then drag the white dotted line to match the width of the area you want to highlight, click again, and repeat until you complete the polygon. Double click to complete the polygon. A shape can also be drawn by clicking and dragging the mouse across the map and releasing when finished.
Get Summary Statistics
Each polygon you draw will return a histogram with summary statistics for that area and time period, including percent of the total population and minimum, maximum, median estimates of relative abundance. Mouse over the histogram to see abundance range estimates and total count for each bar in the histogram.
Relative abundance is the estimated average count of individuals detected by an eBirder during a 1 hour, 1 kilometer traveling checklist.
For each species, relative abundance is estimated for each week of the year across a regular spatial grid with a density of one location per 2.96 km x 2.96 km grid cell across the Western Hemisphere. Estimates at each location and date are made while accounting for variation associated with search effort, local habitat, elevation, and topography.
Because detecting birds in the environment can be difficult, we know that there are always some individual birds that are missed by eBirders. For this reason, we refer to the quantity estimated as a relative measure of abundance. Although the relative abundance estimates will underestimate the true abundance, they do provide a standardized index that can be used to compare the abundance of a species in different regions. For example, if relative abundance is 10 in one area and 5 in another area, then we would estimate abundance is twice as high in the first area, even if we’re not sure of the actual number of individuals in the area. Learn more about the Status Models used to calculate the data.
Percent of the total population
Percent of the total (Western Hemisphere) population is calculated by dividing the relative abundance at each pixel by the sum of the relative abundance across all pixels for a given week. This allows values to be summed within shapes and for safe comparison across weeks and species.
Minimum, median, and maximum relative abundance
Summary statistics include minimum, median, and maximum numbers of relative abundance. If the polygon you drew includes a lot of area where the species of shorebird is not predicted to occur, the summary statistics will be skewed low due to the inclusion of many zeros in the data set. To see median and maximum values without the zeros, click on the chart options drop down menu and select "remove zeros from histogram".
Zooming to a shape may update the summary statistics of your polygon if the scale of the map changes. Zoomed out views with coarse data representations will produce more heavily averaged summary statistics (e.g., using 27km grid cells, as opposed to 3km grid cells when zoomed all the way in). A polygon must be fully visible on the map to update its summary statistics chart.
Edit a polygon
To modify the shape of your polygon, click the edit shape button on the right panel. Click on a node (white dot) and drag to create the desired shape. Click and hold on the dashed border to drag and move the whole shape. Editing a shape will also zoom to its bounds on the map.
Delete a polygon
To delete a polygon on the map, click on the polygon to select it (when selected the solid line becomes a dashed line) and then click on the garbage icon in the upper left of the screen or in the right side panel below the histogram.
Change the week or species
In the top-left corner of the map, you can update the map and summary statistics with different species and change what week of the year you want estimates of relative abundance for. Each filter change will update the map and summary statistics charts for any polygon on the map.
Export the data
You can export summary statistic results as a CSV or GeoJSON using the export dropdown menu. GeoJSON files are a standardized geospatial data format compatible with ArcGIS, Google Maps, and other software. These GeoJSON files contain the actual geometry of any shapes drawn along with their respective summary stats. These can then be mapped outside of ShorebirdViz.
The shaded portion of the map indicates the “modeled area,” where there was sufficient data to run a model, but the species was predicted to be absent. Sufficient data required there to be, on average, at least 0.5% spatial coverage of 3 kilometer grid cells within the region for a given week. The unshaded portion of the map refers to areas of “no predictions” where there was insufficient data to assess whether the species was present or absent. That is, there was less than 0.5% spatial coverage of 3 kilometer grid cells within the region for a given week.
Options and Settings
Change the opacity of the relative abundance layers with the opacity slider on the right panel.
Change the basemap from satellite to dark mode on the bottom right of the screen.
Change the chart display using the chart options drop down menu on the right side panel.