Sister species range maps

Generating kde-based range maps from observance data

As part of a project with Megan Mitchell and Nicole Creanza, I used BigQuery on the Google Cloud platform to compile sighting records of 42 species of in the Passerellidae family of sparrows. Our goal was to estimate the degree of range overlap for each pair of sister species; we wanted the range to be restricted to breeding season, where applicable, and comparable across species with orders of magnitude differences in number of recorded sightings. For most North American sparrows, thousands of records were compiled on eBird.

An example query of the complete eBird records dataset for one species (Worthen’s sparrow) on the Google Cloud platform.

Below are an example of some basic range maps I generated using different density estimations from one sister species pair.

Range polygons generated by applying different density thresholds to kernel density estimation.

Emily J. Hudson
Emily J. Hudson
evolutionary biologist and data fanatic