Identifying features
Wingspan: 64-76 mm. With its tail and black markings on the yellow wing colour, the swallowtail is distinctive and easily recognisable, even in flight.
Similar species
There are only a few yellow butterflies in Denmark, and the swallowtail, when observed at rest, is unlikely to be confused with other species. In flight, it may, for a brief moment, be possible to confuse swallowtails with clouded yellows.
Distribution
In 1978, the swallowtail butterfly (Papilio machaon) became extinct in Denmark. This was from its last Danish population at Filsø in West Jutland, where it had begun to become increasingly rare over a few years.
Biology
One or more generations during the summer. In Denmark and Sweden there was previously only one, with a few individuals in the 2nd generation in early August.