This year has been incredibly successful for the eastern loggerhead shrike recovery program with a record breaking 128 conservation-bred juvenile shrikes released in Ontario. These releases occurred in the two core breeding areas, Napanee and Carden, where biologists also monitored the wild breeding pairs and their offspring. Monitoring wild shrikes allows us to track their abundance and reproductive success, two key indicators of recovery capability, as well as to determine the return rate of released birds following their first winter in the wild.
Six conservation-bred shrikes released by Wildlife Preservation Canada in 2015 and 2016 returned to Carden this year to successfully raise young. These six shrikes were members of breeding pairs which reared half of the 22 wild fledglings observed in Carden in 2017. An additional two returning shrikes were spotted as transient single birds who may have bred in areas which were not accessible for surveys. At the Napanee site, two returning conservation-bred shrikes paired with wild shrikes and raised seven young out of the impressive 38 total wild fledglings. The contribution of our conservation-bred eastern loggerhead shrikes to the wild population highlights the critical role of the captive breeding program to the recovery of this endangered species.
In 2017, 112 released juvenile shrikes were fitted with a unique combination of four leg bands. The remaining 16 were given one band and a Motus radio transmitter harness to track their movements for the next six months to a year. Both these techniques will help our ongoing efforts to determine the migration routes and overwintering locations of the unique migrans subspecies of loggerhead shrike. It may also help illuminate whether the low return rate for shrikes entering their first breeding season is a result of mortality during migration or over their first winter. Only time will tell us what is going on inside the mind of a travelling shrike!