Gull and tern Nest Stage data
Counts of nesting gulls and terns by site and date in San Francisco Bay from 2014 – 2019. Each row represents the counts for a species during a single visit to the breeding colony. If the volunteer divided the birds into subcolonies then the count for each subcolony occupies its own row.
Field Descriptions:
- ColonyName/ColonyID – A unique identifier for each colony, describing geographic location of colony
- Latitude/Longitude – coordinates in decimal degrees and WGS84
- SubcolonyID – A unique identifier describing an observer-defined geographic subset of the colony (subcolony)
- SpeciesCode – 4 letter code used to identify species
- Standard species code based on common name (e.g. GBHE for Great Blue Heron)
- Visit this page for full list of species
- Stage0Count – Defined as prenesting stage, birds at or near colony, courtship, mating, nest building. Count is number of adults.
- Stage1Count – Defined as egg laying or incubation, adult on nest for long periods, standing to turn eggs. Numbers of eggs will almost always be "unknown", but numbers of nests at stage 1 can be estimated from adult behavior. Count is number of nests.
- Stage2Count – Defined as downy chicks in nest or colony, watch for feeding or adults standing. Count is number of chicks.
- Stage3Count – Defined as larger, at least partially feathered chicks, adults near. Count is number of chicks.
- Stage4Count – Defined as fledging young, fully feathered chicks in colony. Count is number of chicks.
- See Stage Guides for more detail
