Pipevine Swallowtail
Battus philenor

Battus philenor, the pipevine swallowtail or blue swallowtail, is a swallowtail butterfly found in North America and Central America. This butterfly is black with iridescent-blue hindwings. They are found in many different habitats, but are most commonly found in forests. Caterpillars are often black or red, and feed on compatible plants of the genus Aristolochia. They are known for sequestering acids from the plants they feed on in order to defend themselves from predators by being poisonous when consumed. The adults feed on the nectar of a variety of flowers. Some species of Aristolochia are toxic to the larvae, typically tropical varieties. While enthusiasts have led citizen efforts to conserve pipevine swallowtails in their neighborhoods on the West coast, the butterfly has not been the subject of a formal program in conservation or protected in legislation. The butterfly is however of "Special Concern" in Michigan, which is on the Northern limit of its range. Source
Where it is now
In the last 8 weeks this insect was recorded 43 times across 8 areas (each area is a 5 degree square).
See the Pipevine Swallowtail on the live map
Movement and weather
Over the weeks it was present in the past year, its centre in North America ranged from 28°N in October to 38°N in July, 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 | 6 April 2026 | 6 April 2026 | 6 July 2026 | 1 |
Figures are effort corrected and come from automatic sound identification, which makes mistakes. How this is measured and how it compares with human observers.