Shipboard counts · 1969–1990
The ten-minute sea
See where and when sailors recorded seabirds during 10-minute counts.
Observers made repeated counts from ships around New Zealand and across the southern seas. This project follows the 18 most frequently recorded bird groups while keeping the changing survey route in view.
- Full count periods
- 12,111
- Bird rows
- 49,019
- Years covered
- 1969–1990
A full count period is the comparison unit. Seeing a bird at least once counts as one recorded presence, whether one bird or many appeared.
Start with one name in the log.
Choose a bird to update every view. Longer bars mean it appeared in a larger share of the 12,111 full count periods.
2,923 of 12,111 full count periods
Names preserve the dataset’s identifications. “Group,” “unidentified,” and slash-separated names mean the log could not support one exact species name.
The ship did not sample every patch of sea.
Each square covers five degrees of latitude and longitude. Brighter squares mean cape petrel appeared in a larger share of full counts there; the dot shows how many count periods support the rate.
Read the rate beside the effort.
Each column shows the share of full count periods that recorded cape petrel. Choose a year to see the numerator and denominator; the number below each column is the count effort.
Routes, seasons, observers, and annual effort changed. The year-to-year line cannot show a population trend.
The same bird meets a different sea.
Choose a cell. It compares recorded presence by southern-hemisphere season and grouped Beaufort wind class. Darker cells mean a larger share of the available full counts.
Wind was recorded for 7,430 of 12,111 full count periods. Season, route, location, and weather overlap, so this view does not show that wind caused a bird to appear.
Presence is evidence from a route, not a census of the ocean.
The observers counted from ships, mostly while steaming or sailing. The page keeps one presence per bird group per full 10-minute period, then divides by all comparable periods in the same place, year, season, or wind group. That makes survey effort visible without pretending that every sea area received equal attention.
Data preparation and limits
This work uses data sourced from Te Papa. The source contains 12,310 ship count periods and 49,019 bird rows from July 1969 through December 1990. The analysis keeps 12,111 periods marked as full counts and excludes partial or casual observations from every denominator.
Age and plumage suffixes are combined into broader bird groups before ranking. Individual observers, ship names, raw abundance counts, and record identifiers are not published. The page cannot establish population size, abundance change, a complete geographic range, or a causal effect of weather.
The standard-library builder pins three source files to TidyTuesday commit b2258ae949e3c64099c4e6d00ff4b68dba1d6d0e, verifies their byte counts and SHA-256 values, and writes this 105,489-byte static snapshot. The browser makes no data request.