Third times the charm
Posted onNovember 19, 2023by|, , ,
Loggerhead shrikes face a myriad of barriers to their success. From habitat loss to inclement weather to vehicle collisions, these birds can barely catch a break!
With only 22 breeding pairs confirmed in Ontario in 2022, each individual counts for the success of the species in our province.
Inhabiting merely one third of their historical Ontario range, the wild population exists in two pockets; the Carden Alvar and the Napanee Limestone Plain. This year, the Carden population suffered many defeats and was plagued by nest failures. With a conservative estimate of just over a dozen shrikes spotted in Carden this season, the future of the population remains uncertain. But through the doom and gloom there is a spark of hope for this predatory songbird, with an incredible story of parental resilience.
This year, one pair’s relentless nesting attempts truly paid off! Discovered before the deciduous leaves had unfurled, the first nest seemed like a picture-perfect shrike nest; nestled in the middle of a dense hawthorn on a vast native grassland.
The female diligently incubated the nest in early May, and all seemed well, until a cold snap hit Carden two nights in a row, reaching sub-zero temperatures. The next day, our field staff discovered that the eggs had been abandoned, likely due to the female keeping herself warm and sacrificing the first nest attempt.
Shrikes are considered persistent re-nesters, with anecdotes of females laying up to five sets of eggs before successfully raising a brood. But with each renest occurring later in the breeding season, the chance of young surviving decreases. The second attempt was discovered less than two weeks later, only 100m away and right next to a nest from last year. Alas, this second nest was also doomed for failure. In early June, three broken eggs were discovered below an empty nest: a presumed predation event. As the saying goes, if at first you don’t succeed, try and try again!
But insanity is doing the same thing over and over again, expecting different results, right? Our field team became worried when the pair was not spotted in over a week. Had they been
spooked away from their territory or were they trying a third time? Indeed they were! A third attempt was discovered in mid June with five eggs.
Cautiously but hopefully, we monitored the site from afar, until the beginning of July brought the arrival of nestlings! We did not expect all the eggs to hatch, but these birds proved us wrong. All five nestlings were alive and well at their first nest check.
At each visit, we held our breath but kept being happily surprised. They had all survived to the branching stage (early exploration out of the nest into surrounding branches) and were facing their final trial before migration. This is often when the number of successful offspring declines, with mortality recorded between 33-53% in the first 10 days after fledging. Both parents must constantly feed the young and defend them from predators for weeks until the juveniles are finally independent.
Despite the odds, this family continued to stick together, and were seen as a unit five weeks after fledging! This goes to show, you can have all the statistics in the world, but animals can defy them and prove to be resilient.
Through the ups and downs, the shrikes had an overall successful breeding season this year. We found 12 successful shrike nests this year, which fledged 37 new young between the Carden and Napanee core areas. Working with our breeding partner facilities, we also released 17 new captive-bred juveniles into the wild. We are hopeful that these new recruits will return to breed in Ontario again next year!
If you see a shrike, we’d love to know about it! Send sighting details and photos to email@example.com
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