Greetings from Carden, Ontario!
The shrike team is now in full swing with the arrival of June and it’s warm weather! My field partner Sam has joined me for the season, and we’ve doubled our surveying effort. We’ve found a fourth nest this month (Yay!!), and are now starting to see some of the nestlings branch out of the nest – some have even fledged and left the nest tree entirely!
Baby shrikes are altricial, meaning they require parental care for survival when they hatch. The adults take turns feeding the young shrikes for multiple weeks, even after they’ve left the nest tree. The parents teach them how to hunt prey, and often you can see a young shrike practicing it’s impaling skills with a leaf or a prey item provided by one of the adults. With larger clutches, once the young have fledged the parents split up and each care for half of the juveniles. Which is a good idea because the average clutch size is 4-7 eggs!
With hatching babies comes trapping. We try to band the adults we see on site, and the best time to do that is shortly after the eggs have hatched. Their drive to care for the babies decreases the likelihood they’ll abandon the nest after being handled by humans. We use specialized traps that use live bait (don’t worry, the mice are not hurt during the process). The mice are placed in a separate cage inside the trap, just behind a perch that triggers the door when touched. We managed to band two adults so far this year, both from the same breeding pair. The first attempt was not ideal, as the wind was very strong and the temperature was quite cold. It took the better part of an hour to trap the first bird, she managed to fly right into the trap, on to the mouse cage, without triggering the door. Which left us anxiously waiting until we saw the hatch drop and Hazel Wheeler (the Lead Biologist) could run and grab her. After an almost unsuccessful banding we decided to call it for the day as we became concerned about the welfare of the animals (mice and shrikes – plus we were really cold!). Later that week, Hazel came back to trap the male and it went off without a hitch! We even discovered a third shrike on the property!
We did discover a failed nest this year, unfortunately. It appears to have been predated by another bird. After a nest check we found an intact nest complete with lining and no evidence of eggs or nestlings. The pair have since found a new nest tree and have successfully built a new nest. The female is incubating as we speak, and I look forward to watching this second clutch grow up.
The rain hasn’t quite given up yet, and we’ve had more rainy days than I care to have. But, we’re having better weather than we did all May, and I’m hopeful that we will find more shrikes by the end of the month!
Carden Shrike Biologist