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Canada Warbler

Species Spotlight: Canada Warbler

Vital Signs

image of a warbler in a tree

Canada Warbler by Jeff Nadler

Common name: Canada Warbler
Latin name: Cardellina canadensis
Status under SARA: Listed as Threatened under the 2008 assessment.
Range: Found mainly in mixed deciduous-coniferous forests across Canada. Their breeding range is 85% in Canadian territory from the southernmost parts of Yukon and Northwest Territories to the Great Lakes region. The densest populations are in the eastern provinces of Ontario, Quebec and the Maritimes. Their migration ranges over mid-to-eastern United States and they overwinter in the Andean slopes of northern South America.
Life span: Relatively unknown; maximum recorded age was almost 8 years old.
Size: Small warblers; wingspans of 20-22 cm, body length of 12-15 cm, body weight between 9.5-12.5 g depending on before or after migration.
Population estimate:  There are approximately 2.7 million individuals today; however, since 1968, Canada Warblers have been declining at an annual rate of 4.5%.

The Facts

Like most birds, Canada Warblers display sexual dimorphism where males are more brightly coloured than females and juveniles. However, in both sexes, you can see how they got the nickname, Necklace Warbler – the “necklace” refers to the  collar that is formed from the black stripes perfectly placed on their upper-chests.  Canada Warblers also have bluish-grey tails and upper parts, contrasted by bright yellow throats and breasts. Males also have black feathers contouring their foreheads, cheeks and eyes. Unlike most birds, these warblers keep the same plumage all year!

Canada Warblers are found in many types of forests, from conifer swamps to riparian woodlands. However, they are most commonly found in cool, damp, mixed deciduous-coniferous forests with well-developed shrub layers. Females choose areas ridden with dense ferns, mosses, fallen logs or tree stumps to build their nests. Common nest materials include moss, leaf litter and roots.

In late May, Canada Warblers arrive in Canadian territory to begin their breeding season. Females can lay 4-5 eggs and incubation lasts about two weeks. Chicks stay in the nest for 10 days after hatching, before venturing out on their own. Despite this burgeoning freedom, they remain dependent on their parents for another 2-3 weeks.

This warbler is primarily an insectivore, feeding on flying insects such as mosquitoes, butterflies and moths, as well as spiders. Whenever there is an outbreak of Spruce Budworms, you can be sure to find these warblers munching away! They forage until September, and once migration season begins, they embark on their journey to their winter homes in the Andes.

The Story

Eighty-five percent of the global breeding population of Canada Warbler occurs in Canada. For this reason, Canada has a major responsibility for the conservation of this species. However, this warbler also faces problems on migration and in its wintering habitats in the South American Andes, so conservation efforts need to operate on an international scale.

The forests of the northern Andes – the main wintering grounds of the Canada Warbler – are among the most threatened in the world. Approximately 90% of these forests have now been cleared for agriculture, fuel wood, cattle production, and the cultivation of plants such as coffee and coca (from which cocaine is derived)Deforestation pressures and human development projects are of utmost concern. Furthermore, these issues are impacting all three habitat ranges of the Canada Warbler, so these little guys don’t even have a chance to recuperate and re-establish population numbers.

In some parts of its breeding range,  but the high density of  deer  (Odocoileus virginianus),  results in overgrazing of forest habitat,  reducing the shrub layers these warblers are dependent on.

Other breeding ground impacts are believed to including certain forestry practices, forest fragmentation from roads and other infrastructure such as seismic lines in Northern Alberta, and desiccation of habitat from land draining in the south and climate change impacts in the north.

image of a canada warblerWhat’s Being Done

The Canada Warbler International Conservation Initiative (CWICI) was established in 2013 at the BirdLife International Global Congress in Ottawa, with Nature Canada, Bird Studies Canada, Environment Canada, and BirdLife International leading. Nature Canada established the Canada Warbler International Conservation Initiative website as a public face for the initiative.   Environment Canada published a Recovery Strategy for Canada Warbler in 2015 to establish broad goals, strategies and timelines for recovery efforts for this threatened species.  Over the past two years, Conservation Action Plans have been developed for both the wintering grounds in South American and southern Central America, and the breeding grounds in Canada and the USA.  Current efforts are to weave these plans together into a full life-cycle Conservation Action Plan for the species. These effort will direct the very limited conservation resources most effectively where there are needed.  The consensus appears to be that wintering grounds threats require the most immediate attention, and that shade grown, bird friendly coffee could be a big part of the solution.  Do you know where your coffee comes from?   Our coffee should be shade-grown, fair-trade, organic, and ideally certified bird-friendly to support Canada Warbler and many other species of birds and other wildlife.

However, gaps in knowledge still need to be filled to inform effective conservation actions.   Researchers are studying habitat preferences for this reclusive species both on wintering and breeding grounds.  Researchers are also connecting the dots between breeding grounds and wintering areas through the deployment of micro tracking devices such as geolocators.  There is hope that such knowledge will elucidate why the species is declining most rapidly in its eastern breeding range.

On the breeding grounds, we have are engaging the forestry sector, particularly the Forest Producers Association of Canada (FPAC) and the Sustainable Forestry Initiative (SFI) to consider beneficial practices for Canada Warbler with their partners.  We are also aware the Canada Warbler is susceptible to window collision during migration.  We are confident that in mitigating this hazard, we could save many more Canada Warblers from collision.

What You Can Do

There is always something you can do to help, even if it seems small!

Locally

  1. Your support for Canada Warbler can begin with your purchase of coffee.  If you purchase shade-grown, Fair Trade organic coffee from Colombia, Ecuador, Venezuela or Peru, or Central American countries such as Panama, Costa Rica or Nicaragua, you will be supporting the habitat that Canada Warblers use on migration and during their non-breeding season.
  2. Another way of helping the Canada Warbler is to make your home and your town or city safe for them.  That starts by making windows visible to migrating birds.  Many Canada Warblers die from colliding with windows each year.  The problem is twofold – they don’t see them during the day, and they are attracted to them at night during migration. The solution to the last problem is fairly simple – turning off building lights that attract birds at night, or closing blinds and drapes so the light does not escape.  The first problem can be solved by making your windows visible to birds. Visit our Save Bird Lives webpages on reducing window collisions.
  3. Working with groups like FLAP Canada, or Safe wings in Ottawa is very helpful if you want to address this issue at your municipal level.
  4. Another human-related cause of bird mortality that could impact Canada Warbler are cats. Cats kill as many as 200 million birds in Canada each year. Join our campaign to Keep Cats Safe and Save Bird Lives by visiting our Cats and Birds website and signing up!
  5. Finally, consider joining your local naturalist or birding group and participating in Citizen Science projects. See Bird Studies Canada for a full list of great bird-related projects for people like you and me!

Globally

You may not realize it, but many things that we take for granted come from areas that have been deforested for crop production (to produce foods and drinks we love). Be eco-conscious when buying products at the grocery store: for instance, purchase shade-grown coffee and organic chocolate products. Shade-grown crops are planted under forest canopies which respect the habitat requirements of wildlife, like the Canada Warbler.

Resources

Canada Warbler – Nature Canada
Species Profile (Canada Warbler) – SARA
Canada Warbler – Status of Birds in Canada
Canada Warbler – Ministry of Natural Resources and Forestry

Thank you to guest blogger Tina-Louise Rossit and Blair Scott for contributing this species spotlight.

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