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Recovery Strategy for the Horned Lark strigata subspecies (Eremophila alpestris strigata) with consideration for the Vesper Sparrow affinis subspecies (Pooecetes gramineus affinis) in Canada


Executive Summary

This recovery strategy outlines a multi-species approach for the Horned Lark strigata and Vesper Sparrow affinis. It was recognized that there is considerable overlap between these species with respect to current and historical distribution in Canada, general ecological requirements, and principal threats to the species and their habitat. In addition, many of the professional biologists involved have extensive knowledge of both species.  Adopting a multi-species approach to recovery planning also represents an opportunity to make efficient use of conservation resources. Current and historical populations of both species are patchily distributed and, together with isolated populations in the United States, each comprises a single metapopulation in the Pacific Northwest. Thus, recovery of Canadian populations will contribute significantly to the global recovery of the two subspecies.

Horned Lark strigata

The Horned Lark strigata (Eremophila alpestris strigata) was designated as Endangered by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) in 2003.

The Horned Lark strigata is a subspecies of the Horned Lark, a small tan and yellow passerine with a black facial mask and ear tufts or “horns.” The Horned Lark strigata is an open habitat specialist, breeding in both dune and grassland habitats which have a high percentage of bare ground, short, sparse herbs or grasses, and few or no trees and shrubs. No individuals are currently known to occur or breed in Canada, but numerous confirmed historical breeding records exist. The historical distribution of the Horned Lark strigata in Canada is restricted to southwestern British Columbia, where it occurred only on southeastern Vancouver Island and in the lower Fraser River valley from Chilliwack west to the mouth of the Fraser River.

No critical habitat can be identified for the Horned Lark strigata at this time, as it is not known whether sites with suitable habitat remain. The persistence of this species in Canada is threatened primarily by loss or degradation of habitat due to urban and industrial development, increased disturbance at remaining suitable or restorable sites, modern agricultural practices, and infilling of most remaining open spaces by exotic vegetation. In addition, lark dune habitat has been lost due to improved dyking techniques in the Fraser River delta.

The recovery goal for this species is to re-establish a breeding population of at least 10 breeding pairs at a minimum of three sites within its historical breeding range in Canada. Recovery objectives include identification and assessment of suitable and restorable sites, securement and protection of candidate sites, and determination of the feasibility of habitat creation and reintroduction methods. These initiatives should be implemented in cooperation with the Garry Oak Ecosystems Recovery Team Vertebrates at Risk Recovery Implementation Group where appropriate or in partnership with recovery efforts for other listed species that use coastal open habitats.

Vesper Sparrow affinis

The Vesper Sparrow affinis was assessed as Endangered by COSEWIC in April 2006. It is currently under consideration for listing on Schedule 1 of SARA.

The Vesper Sparrow affinis is a subspecies of the Vesper Sparrow, a large sparrow with a whitish eye ring, a chestnut shoulder patch, and white outer tail feathers. Like the Horned Lark strigata, the Vesper Sparrow affinis is a bird of open habitats, favouring areas with a high percentage of bare ground and short, sparse herbs or grasses. In contrast, however, it selects open habitats with scattered trees or shrubs, which it uses for singing perches and escape cover. In Canada, the Vesper Sparrow affinis currently breeds only on Vancouver Island at a single location. Historically, it has been reported during the breeding season on Vancouver Island from the Englishman River estuary in the north to Cobble Meadows and Mill Bay to the south. It was also formerly a local breeder in the Fraser Lowland on British Columbia's southwest mainland coast.

Because the species is not listed on Schedule 1 of the Species at Risk Act, no critical habitat can be identified at this time. Like the Horned Lark strigata, the persistence of this species in Canada is threatened primarily by loss or degradation of habitat due to urban and industrial development, increased disturbance at remaining sites, modern agricultural practices, and infilling of most remaining open spaces by exotic vegetation. In addition, future development at the Nanaimo airport may pose a threat to the persistence of the species in Canada, depending on the specific nature and on-site location of the development. Furthermore, conservation actions at the Nanaimo Airport site, such as habitat modification or enhancement, must be compliant with Transport Canada regulations.  Public safety considerations clearly supersede those governing species at risk where the two are in conflict.

The goal for this species is to re-establish a breeding population of at least 30 breeding pairs at a minimum of at least three sites within its historical breeding range in Canada. Objectives include identification and assessment of suitable and restorable sites, augmentation of the population at the existing site, protection of candidate sites, and determination of the feasibility of habitat creation and reintroduction methods. These initiatives should be implemented in cooperation with the Garry Oak Ecosystems Recovery Team Vertebrates at Risk Recovery Implementation Group where appropriate or in partnership with recovery efforts for other listed species that use coastal open habitats.