Methodology
How is the data generated?
The client-provided data of nest locations and foraging areas was converted into a shapefile in ArcMap. A bounding box of the study area was then determined by combining the coordinates of the most northern location with the most eastern location to create the upper-left corner and combining the coordinates of the most southern location with the most western location to create the lower-right corner of the bounding box. An additional 100m buffer was added to account for the edge effect.
Average Distance Travelled. The spatial analysis was mostly done in ArcMap. However, because the client had asked for various maps to be calculated for individual nests as well as by habitat type, the spreadsheets containing these information had to be reorganized for analysis to be done. Near tables were generated to calculate the distance calculations and were either represented as an attribute of the origin point (usually a nest) or as a buffer polygon. Because not all of the nests had any foraging areas recorded, those nests were taken out as outliers as they would skew several calculations, including the average distance of each nest to their foraging areas.
Range Maps. The range maps and average area used by nests were calculated by creating a polygon for each nest location and using the extents of the foraging locations as the outer points.
Distance to Water and Urban Areas. The distance to water and urban areas from the nest locations were generated using the near function in ArcMap. This gave a distance from the nest to the nearest edge of land that was classified as water and urban, not the center of those land use polygons.
Cavity Availability. The cavity availability analysis took the LEWO nesting locations and the competitor locations and combined the two. Ratios were created as new attributes of the LEWO nest locations to indicate the number of competitors and starlings as well as a ratio for both. These are colour coded to show low, medium, and high cavity availability for each specific nest.
Historical Fires. The wildfire data was sourced from DataBC. As it covered all of British Columbia, it was clipped by a bounding box of the study area to minimize the file size.
Mountain Pine Beetles. The mountain pine beetle data was sourced from the Ministry of Forests, Lands, and Natural Resource Operations’ file transfer protocol (FTP) site. Each year had its own file. The data was clipped by the bounding box of the study area to minimize the file size. As the data contained many instances of trees damaged in some way by pests or diseases other than the mountain pine beetle, only the relevant data was selected to be merged into a new, single file that contained data across all the years.