White-letter Hairstreak
CR

White-letter Hairstreak

Satyrium w-album

UnknownLCEULCEU

Photo: Wikimedia Commons (CC) via https://en.wikipedia.org/wiki/White-letter_hairstreak

Overview

A detailed profile for this species is sourced from the IUCN Red List of Threatened Species as assessments become available.

The White-letter Hairstreak faces severe population declines primarily due to Dutch elm disease, which has devastated its primary host plant, elm trees, across much of its range. Habitat fragmentation and loss of mature elm trees through urban development and agricultural intensification have further reduced available breeding sites. Climate change may also be affecting the synchronization between butterfly emergence and elm leaf development.

Threat summary

Habitat

Mature elm woodlands, hedgerows with large elm trees, and woodland edges where elm species (particularly English elm, wych elm, and field elm) form the canopy. The species requires established elm trees for egg-laying and larval development, typically in areas with some shelter and connectivity to other elm populations.

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Frequently asked questions

Why is White-letter Hairstreak classified as Critically Endangered?
White-letter Hairstreak is classified as Critically Endangered — facing an extremely high risk of extinction in the wild — because population sizes are very small, declining sharply, or restricted to a tiny range. The White-letter Hairstreak faces severe population declines primarily due to Dutch elm disease, which has devastated its primary host plant, elm trees, across much of its range. Habitat fragmentation and loss of mature elm trees through urban development and agricultural intensification have further reduced available breeding sites. Climate change may also be affecting the synchronization between butterfly emergence and elm leaf development.
Where does White-letter Hairstreak live?
White-letter Hairstreak occurs in Albania, Andorra, Armenia, Austria, Azerbaijan, and Belarus (plus 43 other countries). Country-level distribution data is sourced from the IUCN Red List and cross-referenced with GBIF occurrences.
What are the main threats to White-letter Hairstreak?
The main threats to White-letter Hairstreak are ai-1, ai-2, ai-3, and ai-4. The full IUCN-classified threat record for this species is detailed on the species page.

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