Data Analyses?
What data do we collect?
In an hour survey each week during the breeding season we:
Make PIGU population counts
Log visits to burrows (no prey)
Log prey deliveries
Identify prey type for each delivery
Record disturbances
Record tide information
Record weather and water conditions that impact our ability to observe PIGU or impact PIGU activity
Definitions
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The sum of the maximum PIGU count for each colony for each Region over the length of the breeding season.
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A burrow for which a PIGU has been seen entering with and/or without prey. This is considered a burrow in which there is an attempt to breed, successful or not.
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= [2 * Number of Active Burrows/PIGU Population] x 100
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A burrow to which a PIGU has delivered prey. A chick burrow is evidence of successful breeding.
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= [2 * Number of Chick Burrows/PIGU Population] x 100
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Chick raised to fledging; we assume this is indicated by at least four weeks between the first observed prey delivery and the last (time to fledge is 35 days, +/-).
2025 Pigeon Guillemot Breeding Survey Data Results
Thank you to Dave Krause for crunching the data and providing us with these analyses!
B.C. colony and volunteer stats were included on the first slide, but pilot survey data were not included in SSGN’s 2026 analyses. B.C. summary data are presented on their own in the last six slides.