Greetings from Carden, Ontario
The eastern loggerhead shrike breeding season is now well underway with some females in their final days of incubating eggs, and other pairs already busy with nestlings. Loggerhead shrikes generally lay 4-7 eggs, with one egg laid per day. Females incubate the eggs for 16-18 days. During this time the female is primarily on the nest keeping the eggs warm and safe, with short breaks off the nest to forage and preen. The male is generally a supportive partner and will regularly feed the female while on the nest, with some mates being more attentive than others.
We are fortunate to be able to see much of the activity firsthand since loggerhead shrikes generally nest low in trees. The current highlight has been to watch as one of the parents return from their hunting endeavors, zipping back to perch on the edge of the nest to feed their young. As soon as the adult has landed the nestlings’ wavering necks shoot up ready to receive the incoming morsels of food, hoping they will be fed first over their siblings. Both the male and female take turns hunting and feeding the young, which is a full-time job since the nestlings have a voracious appetite due to their rapid growth. In the span of two weeks, the once tiny nestlings will grow to be nearly the size of their parents. Not only are the parents busy with feedings but they are also trying to keep the nest clean. Shrikes along with many other passerine bird species will remove the nestling’s fecal sacs, a convenient package that encompasses the fecal material, from the nest. This is in part to keep the nest clean and to avoid advertising the nest location to unwanted predators. The nestlings will remain in the nest for 16-20 days, growing feathers and building muscle to prepare to leave the nest and start their own journey.
During the spring and summer months, the loggerhead shrike diet mainly consists of insects, with prominent items being grasshoppers and beetles. While walking along a wooden fence lined with barbed wire we came across an impaled beetle, known as the fiery hunter (Callisthenes calidus), which had been nicely stored for a later snack. Loggerhead shrikes don’t have sharp talons for tearing prey items so instead, they use trees with thorns and other sharp objects like barbed wire to be able to pull apart their prey. They also will use the thorn or wire as a means of storage for later retrieval.
It is exciting to watch and (silently) welcome a new generation of shrikes to Carden. Not only do we have the young from the wild pairs we monitor but also we are anxiously awaiting the arrival of the captive-bred juveniles. The captive-bred juveniles will be making their way to Carden in July and August from several of our project partners including the Toronto Zoo, Mountsberg Raptor Centre – Conservation Halton, the African Lion Safari, and the Smithsonian Conservation Biology Institute in Virginia. The captive-breeding program is an incredibly vital aspect of the recovery project, which significantly contributes to the steady growth of the population. Special thanks to our project partners and all the hard work that goes into being a ‘bird parent’. We know from watching our shrike parents here that it is no easy feat!
We are looking forward to watching our nestlings grow with time and eventually leave the nest.
Carden Shrike Biologist – Eastern Loggerhead Shrike Recovery Program