It has been an exciting week on the Napanee Limestone Plains in Ontario. Our first batch of conservation-reared eastern loggerhead shrikes arrived, acclimated for 10 days, and were released to the wild. These shrikes are an integral part of the Eastern Loggerhead Shrike Recovery Program as each year conservation-bred shrikes return to the area from migration, find partners and raise wild young.
The week started with seventeen eastern loggerhead shrikes arriving from the breeding facility from our partners at the Toronto Zoo. The 3-hour drive from Toronto to the Kingston-area release site can be stressful even for humans, so the shrikes are put in the pre-release cages to acclimate to their new homes. Throughout the week we must remind ourselves that these birds are intended to be wild, so we limit their exposure to us.
However, there are some very important tasks to complete. The next morning, we weigh and measure the shrikes. We give them a unique colour band combination so they can be identified in the future. We also use different colours of non-toxic marker on the head or breast to help us monitor them in the short term. Some of the larger birds are fitted with a geolocator backpack instead of bands. These allow us to remotely monitor their movements across the continent. With a bit of luck these tools will help us understand where the eastern loggerhead shrikes migrate for the winter.
Every morning and evening the shrikes are served a diet of insects and mice, which is similar to the diet shrikes eat in the wild. These shrikes are in the final stages of growing, so they eat a lot. As a whole the group can go through 1000 mealworms, 255 crickets, and 21 mice a day! We monitor the shrikes while hiding at a distance to make sure they are learning all the necessities for survival, like how to hunt and impale prey. We also make sure the shrikes appear to be happy, healthy, and fit for release.
The day before the shrikes are released, we check them thoroughly by weighing and inspecting them for injuries. This is especially important for birds with geolocators to ensure they are not being impeded in any way. We also give them a dose of West Nile vaccine and refresh their colour markings to make them easier to identify post-release. The birds are more fit and feisty than when they first arrived, indicating they are ready for release.
Finally, the day arrives! The door is opened, and the shrikes are allowed to leave. We perform soft releases where we simply allow the birds to leave on their own time. This creates a less stressful release and allows the shrikes to return if they wish. Some shrikes leave within a few minutes, while others may stay all day.
For the following week, we provide the newly released birds with insects to eat, but they are slowly weaned off the supplementary food. We monitor them throughout the remainder of the summer, but we are hopeful they find wild young to band up with elsewhere.
In one short week, we will repeat the process with a new group! We look forward to seeing our birds return from migration next year and contribute to the recovery of the eastern loggerhead shrike population.