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2.1 Rationale for Recovery Feasibility
Recovery of this species is considered technically and biologically feasible, if limiting factors and threats are adequately addressed (e.g., through habitat restoration).
Immigration from the United States is necessary to maintain the species in Canada. Hence, its recovery in Canada will depend on population trends and recovery activities in the relevant U.S. states. Currently, individual male Henslow’s Sparrows are recorded in Ontario each year. The difficulty of detecting unpaired female Henslow’s Sparrows precludes an estimate of their availability in Ontario. Source populations exist in Indiana, Illinois, New York, Ohio, Pennsylvania, and Michigan. Increasing population density in Illinois, Ohio, and Pennsylvania may allow Henslow’s Sparrow to expand to adjacent states, thus supplementing populations within New York and Michigan.
Sufficient suitable habitat is unlikely to be currently available and secure in Ontario. However, the potential to rehabilitate and maintain suitable habitat is high. Henslow’s Sparrow has shown the capacity to expand into new areas once suitable habitat is available. For example, populations in Pennsylvania increased in the 1980s due to the increased availability of suitable habitat on reclaimed surface mines (Reid 1992; Mattice et al. 2005).
Securing critical habitat areas in Ontario and utilizing appropriate management would help mitigate threats to habitat. Long-term protection and management of rehabilitated habitat might best be achieved on public land. However, collaboration with landholders to encourage compatible land management on adjacent lands would allow for a wider range of habitat values to be provided in the landscape, thereby benefiting a wider array of species. Habitat restoration techniques used in the United States provide a model for success. Establishment of at least 3–4 separate populations in Ontario would mitigate against catastrophic disturbance.
2.2 Recovery Goal
The long-term recovery goal for Henslow’s Sparrow is to increase the Canadian population to a stable annual minimum population of 50 breeding pairs spread among at least three geographically distinct nesting areas over the next 20 years.
Although this population size is not expected to be self-sustaining without immigration from populations in the United States, it is expected to be achievable. In the early 1980s, the Canadian population was at this level, until key habitat became unsuitable through lack of appropriate management (R. Knapton pers. comm.).
The short-term goal over the next five years is to create large patches of suitable, secure grassland habitat at three locations in Ontario.
Establishment of at least three separate habitat locations in Ontario will maximize the probability that suitable habitat will be found by immigrating Henslow’s Sparrows. Establishment of populations at several locations will mitigate against catastrophic disturbance. Isolated habitat patches should be greater than 30 ha and ideally greater than 50–100 ha in size. Several small habitat patches (minimum 30 ha) separated by less than 2 km may together function as a single large habitat patch and will be given preference over small isolated patches during recovery.
2.3 Recovery Objectives
Over the next five years, the recovery goal will be achieved by:
1. locating and securing large habitat areas to provide suitable or potential habitat for Henslow’s Sparrow;
2. creating, restoring, rehabilitating, and enhancing habitat at appropriate sites;
3. ensuring that at least three large (greater than 50 ha), geographically distinct nesting areas are available annually in order to mitigate potential catastrophic effects from disturbance;
4. conducting annual surveys at identified priority locations to determine population status and distribution;
5. establishing at least one stable breeding colony in Ontario;
6. identifying and securing critical habitat and monitoring its condition;
7. establishing a dialogue and relationship with agencies and organizations that are interested in recovery efforts in Indiana, Illinois, New York, Michigan, Pennsylvania, and Ohio;
8. establishing a dialogue and relationship with landholders that are interested in recovery efforts in Ontario; and
9. producing a detailed description of migration and wintering habitat and evaluating its protection status, in cooperation with other species management agencies.
2.4 Approaches Recommended to Meet Recovery Objectives
2.4.1 Recovery Planning
Table 2 outlines a broad strategy to address threats, with reference to the pertinent recovery objective.
2.4.2 Narrative to Support Recovery Planning Table
Lack of suitable, secure breeding habitat is thought to be the primary reason that Henslow’s Sparrow has declined in Canada. Where apparently suitable habitat is available, it is often too small to support Henslow’s Sparrow or lacks important vegetation structural components. Cooperative and voluntary measures will be the primary means used to secure habitat areas. This strategy recommends that habitat creation, restoration, rehabilitation, and enhancement be implemented immediately as the primary tool by which Henslow’s Sparrow will be recovered in Ontario. The success of recovery efforts in Ontario will depend on sufficient source population being available in the United States, and the Recovery Team will need to work closely with agencies and organizations in relevant states.
The creation, restoration, rehabilitation, and enhancement of large areas (greater than 50 ha in size) of grassland habitat potentially adjacent to wetlands or existing protected areas and managed for Henslow’s Sparrow would provide suitable habitat for Henslow’s Sparrow, as well as a range of other at-risk grassland, wetland, and prairie species. Appropriate management of adjacent agricultural areas (such as later-season hay harvesting) would increase the size of habitat area available to Henslow’s Sparrow. Other grassland species not at risk but undergoing range-wide declines, such as the Grasshopper Sparrow and Savanna Sparrow, would also benefit. Henslow’s Sparrow habitat located in native grasslands will provide for native grassland communities. A multispecies approach to recovery should be considered in the action plan.
2.5 Critical Habitat
2.5.1 Identification of the Species’ Critical Habitat
Identifying and protecting critical habitat and monitoring its condition are recovery priorities. However, critical habitat will not be defined until an action plan is developed. Breeding evidence was documented in only nine locations in the 2001–2005 Ontario Breeding Bird Atlas, and much of the formerly occupied habitat is now believed to be unsuitable because of development, conversion to shrubland, or earlier harvesting of hayfields. Consequently, insufficient information is currently available to permit critical habitat to be defined.
Although the literature provides information on the general type of habitat that the species uses, the extent of potential and actual habitat within Ontario is not known. Surveys in 2002 catalogued historical record locations and examined a portion of these sites for Henslow’s Sparrows (Wiercinski 2002). Additional sighting locations since 2002, held by the Natural Heritage Information Centre and identified during Ontario Breeding Bird Atlas surveys, should be added to this list, searched for breeding Henslow’s Sparrows, and their current status as suitable habitat described. Much of this habitat is expected to be now unsuitable for Henslow’s Sparrow.
Critical habitat identification will require an assessment of habitat condition at historical breeding locations and locations at which singing males have been detected since 1980. Priority should be given to the most recent records. However, as much of this habitat is expected to be now unsuitable for Henslow’s Sparrow, this activity should be undertaken concurrently with the identification of large areas of secure grassland that may be candidate areas for habitat creation, enhancement, or restoration. Preferably, these areas of potential habitat will be located on public land or in areas already identified as critical habitat for other species with similar habitat needs to ensure that a stable supply of grassland habitat is identified. These areas will also need to be located in an “open” landscape where there are relatively few forest patches or physical structures such as buildings. The South Cayuga Fields area considered by Enright (1995) should be reconsidered. Historical breeding locations and candidate habitat areas should be surveyed for breeding Henslow’s Sparrow to confirm the breeding status of this species in Ontario and to provide a baseline for subsequent population monitoring.
2.5.2 Schedule of Studies to Identify Critical Habitat
The research activities listed in Table 3 will be incorporated into the action plan for this species.
OMNR = Ontario Ministry of Natural Resources; SARA = Species at Risk Act
2.6 Performance Measures
The recovery strategy and action plan must follow the adaptive management approach, whereby new information feeds back into the plan on a regular basis in order to take advantage of new tools, knowledge, challenges, and opportunities. A five-year evaluation of the recovery strategy will be based upon the performance measures listed below, using 2006 as the benchmark year.
2.7 Effects on Other Species
Recovery efforts that are focused on Henslow’s Sparrows -- especially efforts that are designed to protect, restore, or create grassland habitats -- will benefit a great variety of species. The protection, restoration, or creation of native grasslands will be particularly beneficial. Grassland habitat creation adjacent to wetlands, tallgrass prairie, or existing protected areas will be especially beneficial. Species at risk listed in Table 5 utilize grassland, prairie, or wetland habitats and would benefit from the creation of Henslow’s Sparrow habitat. No species of conservation concern are expected to be detrimentally affected.
2.8 Statement of when one or more action plans in relation to the recovery strategy will be completed
A Henslow’s Sparrow action plan should be completed by August 31, 2010. To address most threats and further delineate critical habitat, a single, overarching action plan is envisaged. This action plan will take a multispecies approach and consider the creation of grassland habitat that will benefit a range of species at risk. Separate management plans should be developed for each identified grassland habitat area to be created, in consultation with other appropriate recovery teams, such as the Tallgrass Communities of Southern Ontario and Walpole Island Ecosystem recovery teams. The overarching action plan will identify the need for, and roles of, any recovery implementation groups.
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