Prepared by Jessica Linton

The Mottled Duskywing (Erynnis martialis) is a medium-sized dark grey/brown skipper butterfly with a very mottled appearance. It occurs in small, isolated colonies in southern Ontario where suitable habitat occurs. Although never documented as abundant in Ontario, recent observations have only noted single individuals or a small number of individuals. The species was classified as endangered by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) in 2012. Following this assessment, the Committee on the Status of Species at Risk in Ontario (COSSARO) assessed and designated Mottled Duskywing as Endangered in 2013, affording it protection under the Endangered Species Act (ESA), 2007.

Threats to the Mottled Duskywing are worsened by their high degree of habitat specificity combined with limited dispersal ability. Threats in Ontario are related to habitat and include: habitat fragmentation, habitat destruction, succession and canopy closure, deer browsing of larval food plants, pesticide use, and competition between larval food plants and aggressive invasive and/or exotic species. The species also has a complex relationship with fire which is not well understood. Frequent and intense fires may lead to direct mortality of individuals and to supressed larval food plant availability. However, the Mottled Duskywing is also dependent on fire (or other disturbances) to maintain suitable habitat conditions.

The recovery goal for Mottled Duskywing is to ensure that existing threats to metapopulations and habitat are sufficiently mitigated to allow for the long-term persistence and expansion of the species into unoccupied suitable habitats. The protection and recovery objectives to meet the goal are to:

  1. inventory, protect and manage extant metapopulations and their habitats;
  2. establish reliable population estimates for all metapopulations and assess theirviability under current conditions;
  3. conduct research on the species’ response to disturbance and climate change toensure proper management of the habitat;
  4. enhance and/or create habitat, where feasible, to increase habitat availability for extant metapopulations; and
  5. augment existing populations, assist colonization to re-establish historicalpopulations at suitable sites, and/or assist colonization in previously unoccupiedsuitable habitats.

It is recommended that areas where populations of Mottled Duskywing occur be prescribed as habitat within a habitat regulation under the ESA. The boundaries of this area should be identified as a buffered Ecological Land Classification (ELC) vegetation type which contain suitable habitat (i.e., Ceanothus plant colonies) and where Mottled Duskywing occurs. It is recommended that potential recovery habitat for the species also be prescribed within the habitat regulation. These areas are identified as buffered ELC vegetation community types containing suitable habitat, which are contiguous to habitat supporting extant populations.