California Tortoiseshell
Nymphalis californica
The California tortoiseshell is a butterfly of the family Nymphalidae. Source
Where it is now
In the last 8 weeks this insect was recorded 19 times across 3 areas (each area is a 5 degree square).
See the California Tortoiseshell on the live map
Movement and weather
Over the weeks it was present in the past year, its centre in North America ranged from 38°N in February to 48°N in June, about 1,100 km apart.
Arrival dates
The week it was first heard regularly in each region, after at least six weeks away. Dates differ from south to north, so a region has a range.
| Region | First arrival | Last arrival | Typical peak | Areas |
|---|---|---|---|---|
| North America | 11 May 2026 | 7 September 2026 | 18 May 2026 | 2 |
Figures are effort corrected and come from automatic sound identification, which makes mistakes. How this is measured and how it compares with human observers.