Oregon Coast Seabird Colony Raw Counts from Aerial Surveys, 1997-2020

1997 marked the start of aerial photographic surveys for nesting seabirds on Oregon's offshore islands. The U.S. Fish and Wildlife Service collected imagery annually, with a subsample of 45 colonies counted over time, including census years 1988, 1994, 2006, and 2014. Raw point counts from non-georeferenced images were archived as geospatial files, with final data published in the authoritative Seabird Colony Count Catalog.

Use Cases

• Monitoring population status and trends based on annual aerial imagery.
• Analyzing long-term seabird colony legacy data as a regional baseline.
• Conducting power analyses for sampling designs based on stratified random subsampling of colonies.
• Studying common murre populations based on the size- and geographical-based sampling approach.

Strengths

• Survey spans multiple years, including census years 1988, 1994, 2006, and 2014.
• A subsample of 45 colonies was counted over time, informed by bio-statistical experts.
• Final count data is curated in an authoritative Seabird Colony Count Catalog by the U.S. Fish and Wildlife Service.

Limitations

• Raw point counts are not registered to geospatial coordinates and only line up with the source image.
• The subsample was selected based on common murre populations, limiting inferences for other species like Brandt's cormorant.
• Column-level documentation is absent; field semantics must be inferred after download.

Provenance

Source

U.S. Fish and Wildlife Service, Oregon Coast National Wildlife Refuge Complex.

Collection Method

Aerial photographic colony surveys, with counts done manually from projected slide images or digitally in GIS.

Time Range

Counts started in 1997 and were completed in 2020, with subsample years including 1988, 1994, 1997, 2000, 2003, 2006, 2009, 2012, and 2014.

Freshness

Last updated 2026-03-04 08:05:45.521420; freshness should be verified.

Geography

Oregon Coast offshore islands.