Breeding Coordinator Jane Spero investigating the wing of a captive-bred loggerhead shrike, which helps to identify the bird’s sex.

It’s the most wonderful time of the year: preparing conservation-bred loggerhead shrikes for release into the wild! Each year, the WPC Shrike Recovery team has been releasing conservation-bred eastern loggerhead shrikes in an effort to help reverse the decline of this critically endangered species. These birds are raised at a few different facilities, including the Toronto Zoo, African Lion Safari, and even some international facilities such as the Smithsonian Conservation Biology Institute. All the shrikes that are released into the wild were hatched this spring, and once they reach a certain age, the birds are transported to outdoor aviaries at release sites in Carden and Napanee, Ontario.

Captive-bred loggerhead shrike prior to processing, left, and right, field intern Emma banding her first bird ever!

In Napanee, our field team received our first group of captive-bred loggerhead shrikes in early July. These birds were outfitted with a stainless steel silver band (with a unique combination of numbers), plus a combination of colour bands so they could potentially be identified in the field with binoculars or a scope. We took important measurements such as weight, wing length, tail length, leg length (also referred to as “tarsus” length), and we took some blood and feather samples for future genetic analysis. Each individual also gets temporarily marked with a colour in a unique spot prior to release, so that individuals can be recognized once they’re out in the wild, but eventually the colour fades away.

A colour-marked (blue head) loggerhead shrike outfitted with a radio-tag. Jane and I are patiently waiting for the glue to dry on the tag.

During this pre-release work, we also assess the overall condition and health of these shrikes. The birds that have the highest weight and best condition will receive a radio-tag. These radio-tags are like a little backpack that’s worn on the back of the bird. The tags have an antenna that sticks out the back, which allows the tag to be detected by the Motus Wildlife Tracking System. The subspecies of loggerhead shrike in Ontario is known as the eastern loggerhead shrike (Lanius ludovicianus migrans), and migrates south during the winter months. As these radio-tagged captive-bred birds begin to migrate, the Motus towers throughout Canada and the US can track the movements of these birds.

We aren’t exactly sure what route eastern loggerhead shrikes take to their over-wintering grounds, but by tagging some birds each year, hopefully we can learn more about their migration patterns.

Alexandra Israel

Napanee Biologist – Eastern Loggerhead Shrike Recovery Program

Alex completed her Master’s degree in Biology at York University, where she studied nest concealment in Wood Thrushes and how it might influence nest success in this Species at Risk. Alex also volunteers much of her time at Long Point Bird Observatory, where she assists with their migration monitoring program each year.

Alexandra Israel