Greetings from Napanee, Ontario
It is an exciting time to be part of the eastern loggerhead shrike recovery team. In mid-July, we received our first group of captive-bred loggerhead shrike fledglings, so for the past couple weeks we have been busy preparing them to be released into the wild. These shrikes are bred at various zoos across North America and are raised by their parents in captivity until they are old enough to be released. Once they are at least 37 days old, some shrike fledglings are transferred to field sites, such as the one here in Napanee, while others are retained to supplement the captive breeding population. When they arrive in Napanee they are put into the release enclosures and allowed to adapt to their surroundings for a week or two. They are fed twice a day on a staple diet of crickets, mealworms, superworms and small mice. Along with food, the shrikes are also given probiotics and vitamins to ensure they are as healthy as possible. Feeding the shrikes live food allows them to practice their hunting and impaling skills on the various thorny branches and barbed wire we have placed around the enclosure. It is vital that we ensure that all the shrikes have these skills before they are released, so we also monitor their activities daily. My favourite observation was seeing one of the captive shrikes impaling an apple slice we had placed in the food corral for the live mouse. I think he was disappointed when he took a bite out of it because he flew off to the insect corral to get some real grub (pun intended).
Shortly after their arrival to Napanee, the captive-bred birds were banded with both silver and coloured bands and various measurements, such as weight, wing length, tail length, and tarsus length, are taken. If a shrike weighs 50 grams or more, then it is considered a candidate for a radio-tag and is equipped with a tiny radio-tag backpack with an antennae sticking out of the end, which runs down along the bird’s tail. These radio-tags work with the Motus Wildlife Tracking System and essentially the way it works is that as the bird migrates, the radio-tag pings off the Motus radio towers, which then tells you when and where a bird is located. After five months, the battery of the radio-tag dies, so the backpacks are designed to naturally deteriorate and fall off on their own, which is great because trapping a loggerhead shrike is no small feat. Once all measurements are taken and bands are put on, each shrike is marked with non-toxic permanent marker for easy identification. Don’t worry, the marker only lasts a couple of weeks!
A day before they are released, each captive-bred shrike is caught and inspected to ensure that they are in optimal health. Radio-tags may be removed if the shrike no longer weighs at least 50 grams or if there are signs that the backpack is causing discomfort. Lastly, their colour markings are brightened with permanent marker again. Now they are finally ready to be released. On the day of release, the enclosure release door is opened and corrals filled with superworms, mealworms and crickets are placed within view of the enclosure to entice the shrikes out. We don’t flush the shrikes out of the enclosure because we want to make sure they enter the real world when they are good and ready. Sometimes that takes several hours, so we simply monitor the enclosure for the first hour and then check in a few times throughout the day. Once we are sure that there are no shrikes left in the enclosure, we shut the door to make sure no one gets trapped inside again. After they are released, we spend at least one week providing them with supplementary food.
Once the supplementary feeding comes to an end, we say goodbye to the captive shrikes that we have grown to love and name and recognise. We wish them well on their upcoming migration to the Southern US and hope that we will be fortunate enough to see them back home on the Napanee Plains next year.
Napanee Shrike Biologist – Eastern Loggerhead Shrike Recovery Program