Prothonotary Warbler

Species information

This chapter provides a review of progress towards the protection and recovery of Prothonotary Warbler in Ontario from 2007 to 2017.

Prothonotary Warbler (Protonotaria citrea) is a small songbird with striking colouration — a golden yellow head, olive-green back and azure wings and tail. White tail spots are also quite prominent. Similar to other warbler species, it only weighs about 14 grams and measures about 14 centimetres in length. The male’s distinctive territorial call is a loud ringing tsweeet-tsweet-tsweet-tsweet, in sets of four or six.

Prothonotary Warbler is the only warbler in eastern North America that builds its nests in tree cavities. The breeding season begins in early May when the males return from wintering grounds. The males often build incomplete dummy nests when establishing territories for females to inspect. A breeding pair is formed when the female chooses a particular dummy nest to complete, or occasionally, builds an entirely new nest within the chosen male’s territory. Five to six eggs are incubated by the female for about 12 days while the male brings her food. The nestlings are fed by both parents and fledge in 10 to 12 days. Both adults and juveniles feed on a wide variety of insects, including caterpillars, flies, midges and spiders. Migration south begins in mid-August.

The breeding range of Prothonotary Warbler is primarily the eastern United States, extending northward into extreme southwestern Ontario. The wintering range extends from southern Mexico to northern South America. In Ontario, the species is found primarily in areas of deciduous swamp forest within the floodplains of slow-moving warm-water creeks along the northern shore of Lake Erie.

Prothonotary Warbler faces several threats to its survival and recovery. The most prevalent and serious threat is loss of its swamp forest breeding habitat through activities such as wetland drainage that deplete local water table levels and remove standing water. Other threats include logging, nest competitors, brood parasitism (for example, Brown-headed Cowbird (Molothrus ater)), nest predators (for example, House Wren(Troglodytes aedon)), and increasing degradation of habitat caused by invasive forest insects (for example, Emerald Ash Borer (Agrilus planipennis)) and invasive plants (for example, European Common Reed (Phragmites australis australis).

The survival and recovery of Prothonotary Warbler are influenced by other factors as well. Long-term climate change could affect water levels in the species’ swamp forest habitat. Also, the restricted distribution and low population levels of the species in Ontario increase its vulnerability to catastrophic events such as flooding and wind storms along the north shore of Lake Erie.

Prothonotary Warbler is listed as endangered at both the provincial level (Species at Risk in Ontario List) and federal level (Schedule 1 under the Species at Risk Act). Globally, the species is considered to be secure (NatureServe Explorer).

Provincial status

Prior to the Endangered Species Act, 2007 (ESA or the Act), the Committee on the Status of Species at Risk in Ontario (COSSARO) assessed Prothonotary Warbler as endangered, and it was regulated under the previous Endangered Species Act in 1999. COSSARO reassessed Prothonotary Warbler in 2017 and reconfirmed its status as endangered. Prothonotary Warbler continues to be listed as endangered under the ESA. In future assessments, COSSARO may consider information gained through protection and recovery actions regarding the species’ threats and trends in population and distribution.

Species and habitat protection

Protecting Prothonotary Warbler and its habitat are key components in the implementation of the ESA and continue to be government-led actions, as identified in the government response statement (GRS). As a species that was regulated under the previous Endangered Species Act, Prothonotary Warbler has received species and habitat protection since 1999 and retained these protections under the ESA. The Act prohibits the species from being killed, harmed, harassed, captured or taken and its habitat from being damaged or destroyed. Habitat protection for this species is based on the general habitat definition in the Act. The ESA does not require a habitat regulation to be developed for transition^{footnote 1[1]} species such as Prothonotary Warbler.

Any person who negatively impacts Prothonotary Warbler or its habitat without prior authorization may be prosecuted under the ESA.

Recovery strategy

A recovery strategy for Prothonotary Warbler was published on June 15, 2012, which was in advance of the date required by the ESA. Recovery strategies are advice to government and represent the best available scientific knowledge. The strategy identifies the habitat needs of the species and the threats that it faces, while recommending objectives and approaches for its protection and recovery. The recovery strategy also includes recommendations on the areas of habitat to be considered in the development of a habitat regulation.

Government response statement

The government published the GRS for Prothonotary Warbler on May 31, 2013. The GRS is the Government of Ontario’s species-specific policy on what is needed to protect and recover the species, and includes an associated recovery goal.

To help achieve this goal, the government leads, supports and prioritizes recovery actions identified in the GRS. Common actions for the government to lead as it works towards achieving a species’ recovery goal are provided in section 2.5 of the Species at Risk Program Status (2008-2015).

The GRS for Prothonotary Warbler also lists eight actions the government supports others to undertake for the species. These government-supported actions fall under the objectives identified in the GRS, which are:

• Enhance, restore, and monitor habitat at current and potential breeding sites
• Improve knowledge of the Prothonotary Warbler population trends and biology, and research and address major threats
• Cooperate with other jurisdictions to improve knowledge and awareness of the Prothonotary Warbler habitat and threats

Government-funded projects

An important government-led action in the GRS for Prothonotary Warbler is to support partners to undertake activities to protect and recover the species. Through the Species at Risk Stewardship Program the government has supported 24 projects ($940,681) designed to contribute to the protection and recovery of Prothonotary Warbler. All 24 projects focused on multiple species at risk, including Prothonotary Warbler. In addition to the government funding, the partners were successful in securing additional funding and in-kind support ($1,702,818) from other sources. This amount includes in-kind support in the form of time and expertise provided by volunteers.

Stewardship partners reported that provincial funding helped them to secure in-kind support by involving 1,479 individuals who volunteered 5,076 hours of their time towards protection and recovery activities for multiple species at risk, including Prothonotary Warbler, which has an estimated value of $179,627. Stewardship partners reported that through both their efforts and the efforts of their volunteers to implement actions contained in the GRS, they were successful in enhancing 134 hectares of habitat that will benefit multiple species at risk, including Prothonotary Warbler. In addition, stewardship partners reported providing ecosystem-based outreach on multiple species at risk, including Prothonotary Warbler to 259,500 individuals.

The remainder of this section highlights two projects supported through the Species at Risk Stewardship Program as well as the corresponding government-supported recovery actions for the species.

Through support from the Species at Risk Stewardship Program a Pelee Island stewardship partner and private landowner, implemented a restoration project to convert 7.3 hectares of marginal agricultural land into habitat for a diversity of species at risk, including Prothonotary Warbler. A major component of the project was the excavation of three irregular-shaped, shallow wetland cells, each about 0.4 hectares in size. Other habitats elements and features were created, including pits and mounds and vernal pools, to begin the process of restoring swamp forest, wet prairie, and wet meadow ecosystems.

Swamp forest is ideal habitat for Prothonotary Warbler. Additional habitat features included the construction and installation of 24 wooden nest boxes, eight per wetland cell, in shallow waters. To discourage predators and competing bird species, the boxes were designed with a 1 1/8-inch entrance hole and fitted with plastic pipe guards over the T-bar supports. Each box was filled with two inches of untreated pine chips. The nest boxes will be maintained through regular monitoring to detect any necessary repairs as well as annual cleaning and refilling with wood chips as needed.

Working in partnership with Essex Region Conservation Authority, native plant species seeds collected in 2012 were propagated in late summer and fall 2013 to produce seedlings. The seedlings were subsequently planted in the spring of 2014 to further enhance the habitat work conducted the previous summer.

This project supports the GRS actions to identify degraded habitat sites with the potential to be restored as breeding habitat for the species and undertake restoration on a prioritized basis, and monitor annual population trends including adult survivorship, site fidelity, return rates, and productivity in Canada in relation to predation, brood parasitism, and nest competition.

Since 2013, the Species at Risk Program has supported several projects led by Bird Studies Canada (BSC) in southwestern Ontario, targeting four high priority forest birds at risk. Over time, the goals of the program have changed, from determining occupancy to monitoring and mitigating threats at occupied sites.

In 2013, BSC received funding from the Species at Risk Stewardship Program to implement a two-year project entitled “Assessing effectiveness of stewardship actions for forest birds at risk.” Four forest bird species at risk were targeted, including Prothonotary Warbler, that all rely on mature forest habitats in southern Ontario. The project objectives relevant to Prothonotary Warbler were to:

• Monitor changes in population abundance and distribution on public and private land
• Identify and monitor potential and existing threats at sites where species at risk occur
• Increase landowner awareness and stewardship for species at risk and assess the effectiveness of stewardship activities through continued monitoring, research and communications with landowners

Key project activities included: site occupancy surveys, landowner contact and interviews, stewardship activities, and habitat mapping. The project results were used to measure the success of the stewardship activities towards the species’ recovery and to prioritize future sites for additional stewardship and conservation efforts.

During the 2013 breeding season, 54 sites were intensively surveyed, primarily in the Norfolk Sand Plain, where known or potential habitat for targeted species at risk exists. BSC staff completed 191 site visits to document nest productivity and habitat associations for the four species, and discovered four Prothonotary Warbler nests. Staff worked with 14 private landowners to access sites and to communicate survey results as well as additional stewardship information and recommendations for the protection and recovery of the targeted species at risk. Several landowners also participated in surveys and/or stewardship efforts. All data was entered into the BSC species at risk database and also submitted to the Natural Heritage Information Centre, Environment and Climate Change Canada, and the Ontario Nest Record Scheme.

In 2014, at a single site, five Prothonotary Warbler pairs (five females and four males) were reported nesting in the same boxes as previous years and at one newly-installed box. Thirty-one chicks successfully fledged and one successful double brood was observed. Interestingly, in one nest box, a Tree Swallow (Tachycineta bicolor) nest with eggs including a Prothonotary Warbler egg was discovered. The Tree Swallows successfully raised the warbler nestling to fledgling along with their own. Prothonotary Warbler was also observed at two new sites. At one site, a nest box was placed in the pond immediately after observing the warblers, and the pair nested successfully, fledging two young. At the other site, a single male Prothonotary Warbler, but no female was observed.

With support from the Species at Risk Program, as well as the Government of Canada and the U.S Fish and Wildlife Service through the international Partners in Flight program, BSC continues to conduct annual surveys in current and recently-occupied Prothonotary Warbler habitat, and has expanded efforts from the Norfolk Sand Plain to across southern Ontario. The year 2017 marked a five-year high for Prothonotary Warblers in Ontario with 25 individuals (11 pairs and three territorial males) documented at seven separate sites. Eleven nests were found and 36 young fledged.

Knowing where birds are is important, but it is only the first step in the species’ recovery. It is also critical to mitigate identified threats to the birds and maintain the species’ habitat at occupied sites. Accordingly, surveying for birds and mitigating threats on an annual basis, as well as engaging landowners, are absolutely integral to Bird Studies Canada’s forest birds at risk program. To date, BSC has engaged over 80 landowners, both public and private, in forest bird conservation and hopes to continue to grow this number. Over the course of the project, BSC, alongside landowners, has assessed threats and improved and restored Prothonotary Warbler habitat at multiple sites. Annual monitoring not only allows us to track Prothonotary Warbler populations but also to assess the effectiveness of our conservation actions.

Surveys for Prothonotary Warbler and other forest bird species targeted by BSC, as well as associated stewardship efforts will continue in 2018.

This project supports the GRS actions to monitor annual population trends including adult survivorship, site fidelity, return rates, and productivity in Canada in relation to predation, brood parasitism, and nest competition and develop and implement best management practices to minimize disturbances such as loss of forest canopy cover and decreasing water levels at occupied Prothonotary Warbler sites.

Species at Risk Stewardship Fund

• 
  24

  projects included Prothonotary Warbler

• 
  $940,681

  for multi-species projects that included Prothonotary Warbler

• 
  $1,702,818

  in additional funding and in-kind support

• 
  1,479

  volunteers

• 
  5,076

  volunteer hours

• 
  259,500

  people received outreach

• 
  
  
  134

  hectares of habitat enhanced

Efforts to minimize adverse effects on Prothonotary Warbler

Supporting partners through permits and their associated conditions is an important government-led action. To date, no permits have been issued for Prothonotary Warbler.

Nine agreements were entered into for Prothonotary Warbler. The agreements were enabled through Ontario Regulation 242/08 (prior to the July 1, 2013 amendment). Conditions of the agreements involve implementing actions in the mitigation plan, including, but not limited to:

• Mapping sensitive areas for the species
• Not undertaking any activities that would disturb nesting habitat or nesting birds unless otherwise authorized
• Monitoring effects of the activities on the species

Nine activities that may affect Prothonotary Warbler or its habitat have been registered for the purposes of Ontario Regulation 242/08 under the ESA. Six activities were registered under ‘Drainage works’ (section 23.9), one activity under ‘Species protection, recovery activities’ (section 23.17), one activity under ‘Threats to health and safety, not imminent’ (section 23.18), and one activity under ‘Wind facilities’ (section 23.20).

The registrations require the registered individual to comply with all conditions of the regulation, such as:

• Creating and implementing a mitigation plan developed by an expert on the species including taking steps to minimize adverse effects on the species and its habitat (for example, avoiding the activity during a time of year when the species is carrying out a life process such as reproduction and rearing)
• Reporting observations of the species to the government using the Ontario Species at Risk Observation Reporting Form
• Creating or enhancing habitat for the species elsewhere in the ecoregion in which the wind facility is located, if reasonable
• Reporting annually on the effectiveness of mitigation actions set out in the plan

Occurrences of Prothonotary Warbler in Ontario

Nineteen populations^{footnote 2[2]} of Prothonotary Warbler have been documented in Ontario. Eleven are considered to be extant (i.e., observed within the past 20 years), two populations are considered to be historical, and five are considered to be extirpated. One population is ranked as Failed to Find. ^{footnote 3[3]}

The extant populations are located primarily in southwestern Ontario along and near the Lake Erie shoreline at Pelee Island, Holiday Beach, Port Rowan and Rondeau Provincial Park. On Lake Ontario, Cootes Paradise at Hamilton is the site of an extant population.

Since 2008 the government’s central repository at the Natural Heritage Information Centre (NHIC) has received 2,315 records of the species. These records are based on observations between 1931 and 2016 and come from a variety of sources; approximately 470 of these observations occurred since 2008. Records submitted have helped to refine where the species is known and has been known to occur and have provided additional information on the species’ habitat and threats.

In 2008, NHIC merged and renamed two populations: the former Point Pelee National Park population is now known as Leamington to Wheatley, and Big Creek Prothonotary Woods is now known as the Big Creek South/Hahn Woods population. The Leamington to Wheatley population was considered to be extirpated in 2008, but subsequent observations have resulted in reclassifying this population as extant. Through follow-up monitoring in 2015 and 2016, an additional population of Prothonotary Warbler was discovered, known as the Princeton population. One nest was discovered and monitored there in 2016 – the first in Brant County.

It is possible that there are observations of Prothonotary Warbler that have not been submitted to the government. Encouraging the submission of observations of this species to the government is included in the GRS as a government-led action. Submission of species observations increases our knowledge of where they occur and can play an important role in assessing the viability of species populations.

Everyone is encouraged, or may be required by an authorization or approval, to submit observations of Prothonotary Warbler, and any other species at risk observed, to the government’s NHIC for incorporation into the provincial record of observations.

Summary of progress towards meeting the recovery goal

Summary of progress

Progress has been made towards all of the government-led actions and the majority of the government-supported actions outlined in the GRS for Prothonotary Warbler. The Government of Ontario has directly undertaken actions to:

• Educate other agencies and authorities involved in planning and environmental assessment processes on the protection requirements under the ESA
• Encourage the submission of Prothonotary Warbler data to the government's central repository at the NHIC
• Undertake communications and outreach to increase public awareness of species at risk in Ontario
• Protect the Prothonotary Warbler and its habitat through the ESA
• Support conservation, agency, municipal, industry partners and Indigenous communities to undertake activities to protect and recover the Prothonotary Warbler Support will be provided where appropriate through funding, agreements, permits (including conditions) and advisory services
• Establish and communicate annual priority actions for government support in order to encourage collaboration and reduce duplication of efforts

Government-supported actions are organized under recovery objective focus areas. Progress has been made towards all of the government-supported recovery objectives and the majority of the associated actions identified in the GRS for Prothonotary Warbler.

Under the objective to enhance, restore, and monitor habitat at current and potential breeding sites, considerable progress has been made towards Action No. 1; progress has been made towards Action No. 2 and Action No. 4; and initial progress has been made towards Action No. 3:

• Identify degraded habitat sites with the potential to be restored as breeding habitat for the species and undertake restoration on a prioritized basis (Action No. 1 – High Priority)
• Develop and implement best management practices to minimize disturbances such as loss of forest canopy cover and decreasing water levels at occupied Prothonotary Warbler sites (Action No. 2 – High Priority)
• Develop and implement approaches to mitigate the threat of invasive forest insects and plants (Action No. 3)
• Investigate and implement techniques to reduce nest failures attributable to competition from House Wrens (Action No. 4)

All of these actions have been implemented through projects supported by the Species at Risk Stewardship Program. A number of projects included activities to identify potential habitat, create habitat areas and install nesting boxes (Action No. 1), educate landowners about the importance of protecting Carolinian forest habitat (Action No. 2), and investigate the degree of threat to Prothonotary Warbler habitat posed by invasive plant species (Action No. 3). Other stewardship projects focused on activities such as monitoring nest boxes and re-locating or modifying the boxes to reduce competition by the House Wren, a known threat to Prothonotary Warbler.

Under the objective to improve knowledge of Prothonotary Warbler population trends and biology, and research and address major threats, considerable progress has been made towards Action No. 5:

• Monitor annual population trends including adult survivorship, site fidelity, return rates, and productivity in Canada in relation to predation, brood parasitism, and nest competition (Action No. 5 – High Priority).

A number of projects that received funding from the Species at Risk Stewardship Program included components that support this action. Species experts conducted surveys and monitoring projects and provided quality datasets to the NHIC.

Under the objective to cooperate with other jurisdictions to improve knowledge and awareness of the Prothonotary Warbler habitat and threats, progress has been made towards Action No. 7 and considerable progress has been made towards Action No. 8.

• Work in partnership with U.S. partners and collaborators in Great Lakes states and other researchers, agencies, and jurisdictions across the species' range to share information about: locations of important wintering areas; the protection status of wintering habitat; and threats impacting the species across its range (Action No. 7)
• Develop outreach materials that highlight ways to minimize threats and disturbances to the species and its habitat, and distribute these materials to the public and other key stakeholders (Action No. 8)

The government is a member of several federal-provincial task groups and organizations that work cooperatively towards the protection and recovery of species at risk, including migratory birds. Through the Species at Risk Stewardship Program, a number of Prothonotary Warbler projects have been implemented by organizations such as the Pelee Island Bird Observatory and Bird Studies Canada that support long-term national and international migration monitoring research. A number of projects that received funding from Species at Risk Stewardship Program included strong education and outreach components; some programs were curriculum-based for delivery at local schools; others involved working directly with landowners to demonstrate effective stewardship actions on their properties.

The recovery goal for the Prothonotary Warbler is to enable natural increases to achieve historic population levels of 40 breeding pairs of the species within its range in southern Ontario. Effort made towards the government-led and government-supported actions has helped to make progress towards the recovery goal for Prothonotary Warbler. Stewardship partners, both individuals and organizations, have implemented a number of habitat enhancement and nest monitoring activities for Prothonotary Warbler with positive results: a new population was recently discovered and an extirpated population reclassified as extant.

Recommendations

As stated in the GRS, the review of progress towards protecting and recovering Prothonotary Warbler can be used to help identify whether adjustments are needed to achieve the protection and recovery of the species. Based on progress to date, the overall direction provided in the GRS for Prothonotary Warbler should continue to guide protection and recovery actions for the species, particularly for those actions identified as high priority in the GRS. Relative to actions that have received a high level of support, the following actions have received less support and may be considered in future decisions regarding the protection and recovery of the species:

• Develop and implement approaches to mitigate the threat of invasive forest insects and plants (Action No. 3)
• Investigate whether insect control programs (for example, for mosquitoes or gypsy moths) directly or indirectly impact the species during the breeding season (Action No. 6).

Moving forward, protecting and recovering Prothonotary Warbler will continue to be a shared responsibility that will require the involvement of many individuals, organizations and communities. Financial support for the implementation of actions may be available through the Species at Risk Stewardship Program. The government can also advise if any authorizations under the ESA or other legislation may be required to undertake a project. By working together, progress can continue to be made towards protecting and recovering Prothonotary Warbler in Ontario.

Summary of progress towards the protection and recovery of Prothonotary Warbler (2007 to 2017)

Provincial status

Prothonotary Warbler is classified as endangered under the Endangered Species Act, 2007 (ESA). Prothonotary Warbler was also listed under the previous Endangered Species Act and has retained the same status since transition to the ESA. Prothonotary Warbler has received species and habitat protection since 1999.

Species-specific documents and guidance published by the government

• Recovery Strategy for Prothonotary Warbler (2013)
• Prothonotary Warbler: Ontario Government Response Statement (2013)

Government-supported stewardship projects

• Through the Species at Risk Stewardship Program, the Government of Ontario has enabled its stewardship partners to conduct 24 projects ($940,681) that have supported the protection and recovery of multiple species at risk, including Prothonotary Warbler.
• The government’s support helped its stewardship partners to involve 1,479 individuals who volunteered 5,076 hours of their time towards protection and recovery activities for species at risk, including Prothonotary Warbler. The estimated value of these voluntary contributions, as well as additional funding and in-kind support, is $1,702,818.
• Stewardship partners reported that through their actions 134 hectares of habitat were enhanced for Prothonotary Warbler and other species at risk that inhabit the same ecosystem.
• Stewardship partners reported providing outreach on multiple species at risk including Prothonotary Warbler to 259,000 individuals.

Supporting human activities while ensuring appropriate support for species recovery

• Nine agreements were entered into for Prothonotary Warbler. The agreements were enabled through Ontario Regulation 242/08 (prior to the July 1, 2013 amendment).
• Nine activities have been registered for the species. The activities were registered under Drainage works (section 23.9), ‘Species protection, recovery activities’ (section 23.17), ‘Threats to health and safety, not imminent’ (section 23.18), and ‘Wind facilities’ (section 23.20) under Ontario Regulation 242/08 of the ESA.

Occurrences and distribution

• Nineteen populations of Prothonotary Warbler have been documented, primarily along or near the shoreline of Lake Erie in southwestern Ontario. Currently, 11 of these populations are extant, two populations are historical, and five are extirpated. One population is ranked as Failed to Find.
• The Leamington to Wheatley population was considered to be extirpated in 2008, but subsequent observations resulted in reclassifying this population as extant. Through monitoring efforts in 2015 and 2016, an additional extant population of Prothonotary Warbler was discovered, known as the Princeton population. These monitoring results, together with efforts to enhance the species’ habitat, demonstrate progress toward the recovery goal for Prothonotary Warbler.

Related information

• Categorizing and Protecting Habitat under the Endangered Species Act
• Natural Heritage Information Centre
• Ontario’s Endangered Species Act
• Ontario’s Endangered Species Act Regulation 242/08
• Ontario Recovery Strategy and Government Response Statement for Prothonotary Warbler
• Policy Guidance on Harm and Harass under the Endangered Species Act
• Species at Risk in Ontario List
• Species at Risk Stewardship Program