Species Classification

The list of species in included in this website is taken directly from "The Moths and Butterflies of Great Britain and Ireland" by Emmet and Heath. This website acknowledges that, in the modern age, there is an increasing occurrence of accidental releases (from butterfly farms and amateur breeders), deliberate releases, and accidental introductions through international travel. This website disregards such sightings, although some historical records are noted. The species represented in this website are divided into 2 categories - primary and secondary. This distinction is subjective and does not stand up to scrutiny!

Primary species are those typically found in modern literature, and represent those species considered resident, extinct, or regular migrants.
Secondary species are those that are often omitted from such works, and represent all other species.

The inconsistency in the literature is largely down to the criteria used to define a species as having occurred in the British Isles. The broad spectrum of possibilities includes residents, migrants, extinctions, reintroductions, accidental introductions, deliberate introductions, unknown and so on. In order to leave "no stone unturned" all species are considered in this website.