The Carden Alvar is one of the last two nesting strongholds (Carden
and Napanee) of the endangered Loggerhead Shrike in Ontario. The
shrike is a high priority bird sought by birders visiting the Carden
Alvar. Why is Carden ideal habitat for Loggerhead Shrikes? Below
I’ve divided shrike breeding habitat into three key components:
habitat structure, cattle grazing, and forbs.
In Carden, shrike nesting territories consist of scattered or clumps
of hawthorns bordering wide meadows for hunting. Isolated trees,
shrubs and tall mullein stocks are important lookouts. Shrikes also
prefer short-grass meadows because they typically hunt prey such as
beetles and grasshoppers on or near the ground.
Cattle are essential to the maintenance of shrike habitat in Carden.
Grazing keeps the grasses short and at uneven heights, increasing
diversity. Cattle also attract and disturb insect prey. Ungrazed
pastures become unsuitable breeding habitat for shrikes because they
overgrow with tall grasses, shrubs and trees.