Overview
Project Name
Boulder County Winter Raptor Surveys
Access Level
By Request
Year started
1983
Year Ended
Ongoing
Dataset
BCNA Winter Raptor Survey: Location Counts
About
Dataset summary
Raptor detections on variable length driving transects with locations and age classes in Boulder County, Colorado. This dataset is split into 2 collections: BCNA_TOTALS, the total number of a species seen on the survey route, with age classes, and BCNA_LOCATIONS, the total count of each species seen at a specific location along a route.
Season(s) and frequency
Four surveys between 15 October and 15 March.
Geographic area covered
Boulder County, Colorado, USA
Primary species covered
All raptors, including owls.
Goals
Establish long-term trend data on winter raptor abundance on the plains of Boulder County, Colorado.
Methods
Sampling Design
Manual route selection to provide adequate coverage of all grasslands in the county.
Field methods
Driving transect (see website for details).
Advice
Winter 2025/2026 was the first to utilize the NatureCounts app and provide precise locations for raptors. Previously a grid system was used to identify location. Please contact science@bcna.org for more details. Please contact science@bcna.org when requesting a copy of this dataset for a data sharing agreement.
Partners
Boulder County Nature Association
Boulder County Parks and Open Space
Citation
Boulder County Nature Association. 2026. "BCNA Winter Raptor Survey: Location Counts". Data accessed from NatureCounts, Birds Canada.
