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The UK Bird Atlas

Leach's Storm-petrel (Hydrobates leucorhous)Where and when to see it in the UK

Passage migrant · reporting peaks September · Northern Storm Petrels · BOU category AF

Records to 2026-08-16 · build 2026-08-31

Leach's Storm-petrel (Hydrobates leucorhous)
Alexis Lours, CC BY 4.0, via Wikimedia Commons
Peak months
Leach's Storm-petrel: relative reporting rate by 10 km square, September

Contains OS data © Crown copyright and database right 2026 (grid squares, place names from OS Open Names). Northern Ireland place names: OSNI Open Data, OGL v3.0. County and country boundaries: Office for National Statistics, Open Government Licence v3.0. Coastline: Natural Earth. Bird records from the data partners listed here.

Leach's Storm-petrel has been recorded in 202 of the 2,971 10 km squares covering UK land (7%) in records to 2026. Passage migrant in the UK. Its strongest squares are in England, Scotland and Wales. Reporting peaks in September.

Conservation status: Vulnerable (IUCN Red List, VU)
View on the IUCN Red List
Relative to this species' best squares (how classes are calculated)
Very high
19% or more of visits
High
2% to 19%
Moderate
<1% to 2%
Low
under <1%
Surveyed, not recorded
at least 20 qualifying visits, no record
Insufficient records
too few visits to say
Lighter fill
Few visits, lower confidence
Small dot
Occasional: a single record, or out of season

Seasonality

Reporting rate by month, relative to the peak month
MonthRelative to peakShare of visitsTypical class
January 4%<1%Moderate
February 0%<1%Very high
March 3%<1%Low
April 0%<1%Low
May 1%<1%Moderate
June 2%<1%Very high
July 3%<1%Very high
August 10%<1%Very high
September 100%<1%High
October 66%<1%Low
November 91%<1%Moderate
December 4%<1%Very high

Squares with the highest reporting rate in September

SquareWhereShare of visitsClass
NA10Na h-Eileanan Siar, Scotland100%Very high
NB43Na h-Eileanan Siar, Scotland100%Very high
NG59Sea, off Na h-Eileanan Siar100%Very high
NT37East Lothian, Scotland100%Very high
SC28Isle of Man100%Very high
SD31Lancashire, England100%Very high
SD34Lancashire, England100%Very high
SH43Gwynedd, Wales100%Very high
SH88Conwy, Wales100%Very high
SJ27Flintshire, Wales100%Very high

Spotted an error in a square? Report it and it goes into the review queue. Read the methodology for how classes, flags and sensitive-species rules work. Data to 2026.