VITAL SIGNS

• Common name: Wilson’s Warbler
• Latin name: Cardellina pusilla
• Range: Breed in Northern Canada and Alaska, Wintering occurs in Southern Mexico
• Lifespan: Six years in the wild³
• Size: Typically ranging from 10-12 cm in length, with a wingspan of 14-17 cm²
• Population estimate: 60 million breeding individuals²

THE FACTS

The Wilson’s Warbler feeds by picking insects, spiders, beetles, and caterpillars from leaves and twigs². They are also known to feed on stoneflies, bees, aphids, and mayflies as well as berries, but only during the fall³. The colour of a Warbler can change depending on the time of year, and throughout the seasons can range anywhere from bright yellow to olive green to black³. Spring males have bright yellow heads with a black patch on their crowns. Female Wilson’s Warblers are often smaller than males, and their appearance in the springtime differs from males, as they have smaller caps and duller brown colours. In terms of behaviour, these birds are constantly moving-either hovering over, or diving into the foliage for prey. 

They also have a variety of call patterns and songs, which vary depending on their age and gender. While all individuals of this species have a song, the purposes differ, and females will have a higher-pitched song³. Breeding grounds are typically near water sources such as streams, lakeshores, and bogs in mountain meadows and thickets².

THE STORY

The population of the Wilson’s Warbler has unfortunately declined approximately 61% since 1966, according to a 2015 North American Breeding Bird survey². The main threat to the Wilson’s Warbler is habitat loss in their breeding areas and wintering grounds. This is mainly due to an increase in development, urbanization, and human interactions. The species is also often preyed on by domestic cars, rattlesnakes, smaller hawks, and weasels. 

WHAT IS BEING DONE

Classified as a species of “Least Concern” under IUCN Global¹. According to a 2010 report by Wild Species Canada, the population was designated as “Secure”¹. The Bird Conservation Region Strategy established by Environment and Climate Change Canada listed Wilson’s Warbler as a “Priority Species”¹. A 2014 State of the Birds report listed the species as a common bird in steep decline². 

WHAT YOU CAN DO

Create bird-friendly areas on your property by providing native trees and shrubs. Advocating for the protection of wildlife in urban areas is a great way to help the Wilson’s Warbler and many other species!

Get involved with a local Bird Team in your community to work towards becoming Bird Friendly City Certified as well as hosting and participating in an upcoming World Migratory Bird Day event near you!

¹Status of Migratory Birds in Canada: Wilson’s Warbler. 2014. Government of Canada https://wildlife-species.canada.ca/bird-status/oiseau-bird-eng.aspx?sY=2014&sL=e&sM=c&sB=WIWA
²The Cornell Lab, 2019. All About Birds: Wilson’s Warbler https://www.allaboutbirds.org/guide/Wilsons_Warbler/id#
³Paniagua-Ugarte, C. 2018. “Cardellina pusilla” Animal Diversity Web. https://animaldiversity.org/accounts/Wilsonia_pusilla