Kirtland's warbler (Dendroica kirtlandii) recovery strategy: chapter 2


2.1          Rationale for Recovery Feasibility

Recovery of Kirtland’s Warblers in Canada is considered biologically and technically feasible.

First, an expanding source population exists in nearby Michigan. As the Michigan population is increasing, available territories may be reaching their carrying capacity, and juvenile males may disperse more widely to reach new territories.It is increasingly possible that a nesting pair of Kirtland’s Warblers will become established in Ontario. Breeding was confirmed only through intensive searches in the Michigan Upper Peninsula in 1995 (Probst et al. 2003). Singing males have been documented less than 25 km from the Canadian border near Sault Ste. Marie (S. Sjogren, pers comm., 2006). Dispersal distances of juvenile males of up to 350 km have been reported, and large water bodies do not appear to present a barrier (Probst et al. 2003). The expansion of the Michigan population to the state’s Upper Peninsula provides evidence that the species has the capability to disperse and establish successfully where conditions are favourable.

Second, it is likely that there is sufficient habitat to establish an initial population in Ontario and ample habitat that could be managed to sustain a population over time. In 2005, 90% of Michigan’s Kirtland’s Warblers nested in jack pine plantations established specifically for the species, suggesting thatactive management can be instrumental in recovery success(P. Huber, pers. comm., 2006).

Third, the U.S. experience has demonstrated that it is possible to reduce threats enough for populations to recover. Evidence suggests that it would be possible, with sufficient resources, to reduce the probable threats in Ontario, mainly through the use of specialized forestry prescriptions, reducing cowbird populations, and limiting site access, if necessary. Finally, these and other successful recovery techniques have been well documented in publications and through contact with the U.S. recovery team and other specialists (Michigan Department of Natural Resources 2005).

2.2          Recovery Goals

The recovery goals are:

a)   to determine if a breeding population exists in Canada; and

b)     to manage habitat at selected locations in Canada to encourage the recovery of the species.

Establishing a numerical population target and specific geographic distribution goal is not currently possible in the absence of confirmed breeding of Kirtland’s Warblers in Canada. If a breeding population is discovered, sufficient monitoring and research should be undertaken in order to determine reasonable population and distribution goals within five years. Although a breeding population has not yet been detected in Canada, breeding was only relatively recently confirmed in the Michigan Upper Peninsula, and the Michigan population reached a record high of 1478 singing males in 2006. For these reasons, habitat should be managed in Ontario to support potential further expansion of the global range of the Kirtland’s Warbler into Canada.

2.3          Recovery Objectives

The following recovery objectives will be addressed between 2006 and 2011:

1.     Identify, survey, and map suitable and potentially suitable habitat for the Kirtland’s Warbler.

2.     Follow up on breeding evidence for the species in Canada, particularly in Ontario.

3.     Achieve a high degree of interorganizational commitment and sustained cooperative management of the recovery program among responsible and interested agencies and organizations -- e.g. CWS, OMNR, the Department of National Defence (DND), forestry companies, and the U.S. Department of Agriculture (USDA) Forest Service.

4.     Encourage the maintenance and/or improvement of large stands of appropriately stocked jack pine in appropriate areas of Ontario through the forest management planning process.

5.     Ensure that landowners, other affected groups (e.g. resource-use companies), and the general public are aware of and consider the needs of the species.

A breeding population may not be located prior to 2010; therefore, the following objectives may not be addressed before that time:

6.     Identify and protect critical habitat.

7.     Conduct an annual census, and collect information on breeding habitat characteristics and threats.

Without a coordinated survey effort, breeding Kirtland’s Warblers are much less likely to be documented in Canada. Targeted surveys to locate and map suitable habitat and breeding populations are critical, because many areas of suitable habitat are difficult to access. Documentation of the population’s expansion into Michigan’s Upper Peninsula and Wisconsin was made possible through intensive annual searches over two decades by staff from the U.S. Fish and Wildlife Service and the USDA Forest Service (Probst et al. 2003).

Encouraging early communication between organizations and agencies, including federal and provincial government agencies as well as forest licensees, will help to create support for and awareness of Kirtland’s Warbler conservation requirements. In the event that a population is discovered, preexisting awareness may speed recovery efforts. The importance of cooperation should not be underestimated. A high degree of interagency commitment, early consensus on science-based recovery goals, and sustained cooperative management in Michigan’s Kirtland’s Warbler recovery program are regarded as major reasons for the remarkable recovery of the species in the United States (Solomon 1998).

Following confirmation of breeding, site protection is critical to ensure breeding success. The Kirtland’s Warbler is an extremely rare bird and is likely to generate considerable interest within the Ontario naturalist and birding communities. However, human disturbance needs to be minimized to ensure breeding success. An annual census, threat identification, and habitat research will help to assess recovery targets, threats, and management needs specific to a Canadian population. Communication with landowners, land managers, and other affected groups will encourage recovery success through stewardship.

2.4          Approaches Recommended to Meet Recovery Objectives

Strategies will include habitat and population surveys to identify potential breeding habitat and detect breeding birds, communication, and habitat management, as required. If breeding is confirmed, strategies will include habitat protection, monitoring, research, habitat management, communication, and education. Habitat management will utilize techniques and expertise documented in Michigan and developed in Canada. The results of habitat and population surveys will be used to determine the need for and timing of habitat management. Habitat management may be implemented prior to the detection of a Canadian population to encourage the establishment of and to benefit the global population.

2.4.1      Recovery Planning Table

Table1. Strategies to effect recovery
Priority Objective No. Broad Approach/ Strategy Threat addressed General Steps Outcomes (measurable targets)
High 1,2 Survey N/A

·   Adopt standard survey methods for suitable habitat and breeding birds.

·   Develop annual survey plans.

·   Complete targeted reconnaissance surveys wherever suitable habitat is found, especially near Thessalon, Chapleau/Gowganda, Cartier/Lake Wanapitei, Petawawa/Renfrew County, the Bruce Peninsula, Manitoulin Island, and Barrie/Orillia areas.

·   Compile all information in a central location, and coordinate annual efforts based on previous results. Share data with other interested agencies.

·   Investigate incidental reports of singing males in suitable habitat within the same season to confirm breeding if possible.

·   Methods identified, targeted exploratory surveys completed.

·   Establishment of a central location and contact for all Kirtland’s Warbler survey results.

·   Relevant incidental reports followed up.

·   Mapping of suitable habitat and high-potential sites completed.

Low 1 Research N/A ·   Consider satellite or radiotelemetry techniques to follow migrating Kirtland’s Warblers located in Canada to possible nesting sites. ·   Telemetry used to locate nesting sites of migrating birds.
Moderate 3 Communication N/A

·   Encourage communication among OMNR, CWS, and others in coordinating survey efforts.

·   Encourage awareness of the Kirtland’s Warbler at a management level to facilitate rapid site protection if required.

·   Working relationship in place among jurisdictions.
Upon breeding: High 6 Habitat protection N/A

·   Gain rapid support for site protection from landowners and/or managers, including OMNR, DND, private landowners, or the forest industry.

·   Close sites to public entry May 1 – August 15 if necessary (Sykes 1997).

·   Protect the breeding population from cowbird predation if required.

·   Site(s) protected from disturbance and public access in year of discovery.

·   Access to sites limited or controlled.

·   Assess need for cowbird control in year of discovery and implement control if required.

Upon breeding: High 6, 7 Monitoring N/A

·   Conduct annual population census following Michigan methods.

·   Assess need and objectives for banding.

·   Annual census data collected and distributed to responsible jurisdictions and U.S. Recovery program.

·   Banding completed.

Upon breeding: High 6, 7 Research All

·   Investigate breeding habitat characteristics and compare with suitable Michigan sites.

·   Identify threats (e.g. determine the extent of suitable habitat near the site and the level of cowbird predation).

·   Habitat characteristics identified.

·   Major threats identified.

Moderate 4, 6, 7 Habitat management All

·   Consult with species specialists, including the staff involved in the U.S. Recovery program, to identify management requirements and determine an appropriate time frame for actions.

·   Consult with Registered Professional Foresters of the OMNR.

·   Undertake any actions required, and monitor results. Adapt future actions depending upon success.

·   Management actions identified.

·   Required habitat management completed.

·   Monitoring of management actions in place.

Moderate 5 Communication All

·   Establish communication with affected landowners.

·   Encourage habitat stewardship and support through education and forest management planning.

·   Pursue further cooperation with U.S. recovery team.

·   Support and assistance obtained from landowners, land managers, and volunteers.
Moderate 5 Education All ·   Educate the public (local and province-wide) about Kirtland’s Warbler conservation through field naturalists and media. ·   Increased public awareness of Kirtland’s Warbler conservation and habitat.

2.5          Critical Habitat

2.5.1      Identification of Critical Habitat for the Kirtland’s Warbler

Critical habitat is defined as “the habitat that is necessary for the survival or recovery of a listed wildlife species” (Species at Risk Act, Statutes of Canada 2002, c. 29, s. 2). Critical habitat for the Kirtland’s Warbler in Canada can be fully identified only once evidence of breeding is documented. Once breeding is documented, a method to locate and identify critical habitat characteristics in Ontario will be determined (see section 2.5.2 below).

2.5.2      Schedule of Studies

Table2.  Schedule of Studies

Table2. Schedule of Studies
Targeted completion date Research required Anticipated benefit
2006–2009 Complete surveys and ground-truthing wherever suitable habitat is found, including Thessalon, Chapleau/Gowganda, Cartier/Lake Wanapitei, Petawawa, Manitoulin Island, the Bruce Peninsula, and Barrie/Orillia Provide focus for survey and monitoring efforts, coordinate data
2007–2011 Select high-potential sites and monitor annually Locate breeding populations
2006–2011 Continue to undertake surveys and document suitable habitat in other areas of Ontario Locate breeding populations
Within one season of breeding confirmation Determine a method to locate and identify critical habitat and complete mapping Map critical habitat for known breeding occurrences
Within one season of breeding confirmation Describe habitat in Canadian breeding locations: vegetation communities, density and cover, other habitat features, etc. Obtain site-specific habitat information; inform management
Annually upon breeding confirmation Complete annual census of Canadian population Set population targets for recovery in Canada
Upon breeding confirmation Completely identify potential critical habitat Critical habitat identified

2.6          Existing and Recommended Approaches to Habitat Protection

Lack of knowledge about the location of any Kirtland’s Warbler habitat precludes any site-specific recommendations for habitat protection. Areas located during surveys that fit the habitat attributes for theKirtland’s Warbler (or areas that could be managed to fit these attributes) should be considered as a high priority for stewardship. Once breeding evidence is found and critical habitat can be identified (as above), land ownership will be identified and appropriate effective protection methods determined. Development of conservation agreements will be favoured.

2.7          Performance Measures

Recovery will be considered successful if a breeding population is discovered in Canada and appears to be increasing in number and/or distribution within the next five years. Clearly, this depends on the arrival or discovery of breeding birds in Canada.

If targeted reconnaissance surveys have been undertaken, incidental reports have been investigated, the Michigan population continues to increase, and no breeding birds have yet been discovered in Canada, a reevaluation of the recovery objectives should be undertaken in five years to determine whether habitat is limiting the establishment of the Kirtland’s Warbler.

If a breeding population has been detected, other indicators of success include:

·       success at protecting breeding site(s), as required, through communication, stewardship, and legislative tools available;

·       completion of annual census and banding;

·       completion of site-based research, especially to determine threats to the Canadian population;

·       completion of a management plan for the site(s);

·       status of management actions (e.g. rotational harvest, cowbird control); and

·       extent of awareness of landowners, managers, and the general public, and their involvement in the recovery process.

2.8          Effects on Other Species

The recovery activities outlined for the Kirtland’s Warbler (i.e. continued surveys) will enable further information to be gathered on common species associates in migratory or breeding habitats for Kirtland’s Warblers in Ontario. Negative impacts on other non-target species will be limited. If management activities are undertaken, impacts on non-target species will be assessed and mitigating measures considered. If other species at risk are found to be present within an area identified for management, the respective recovery teams will be consulted to determine the probability of impact on the species and, if possible, how to manage activities for the benefit of all species within the ecosystem.

2.9          Recommended Approach for Recovery Implementation

The Kirtland’s Warbler is being considered in a single species recovery strategy because of its specialized habitat and management requirements. However, there is potential to incorporate Kirtland’s Warbler recovery with other conservation efforts. In Michigan, species found in Kirtland’s Warbler habitat include Vesper Sparrow (Pooecetes gramineus), Chipping Sparrow (Spizella passerina), Brown Thrasher (Toxostoma rufum), Nashville Warbler (Vermivora ruficapilla), Yellow-rumped Warbler (Dendroica coronata), Hermit Thrush (Catharus guttatus), Clay-colored Sparrow (Spizella pallida), Black-capped Chickadee (Poecile atricapillus), Eastern Bluebird (Sialia sialis), Sandhill Crane (Grus canadensis), and Sharp-tailed Grouse (Tympanuchus phasianellus) (Mayfield 1960; anonymous reviewer, pers. comm., 1999; S. Sjogren, pers. comm., 2006). The U.S. Kirtland’s Warbler program, although focused on a single species, incorporates an ecosystem approach to the management of the jack pine community of the dry sand plains in Michigan (Probst and Ennis 1989; Kepler et al. 1996). Because Kirtland’s Warblers benefit from large forest tracts (Anderson and Storer 1976; Mayfield 1993; Sykes 1997), recovery actions may also benefit other species with similar requirements. Members of the U.S. Kirtland’s Warbler Recovery Team provided valuable input to this recovery strategy, and several are also interested in assisting with survey work in Canada. Further and more coordinated cooperation with the U.S. Kirtland’s Warbler Recovery Team should be pursued.

There may be an opportunity to incorporate the Kirtland’s Warbler recovery activities into future species at risk work at CFB Petawawa.

2.10    Statement of When One or More Action Plans in Relation to the Recovery Strategy Will Be Completed

An action plan will be completed for the Kirtland’s Warbler by November 2010. It is anticipated that the Recovery Team will oversee the recovery strategy and action plan.

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