Nature Reflections November 18, 2004
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Shrikes At one time the Loggerhead Shrike was fairly frequent in eastern Ontario, but over the last 50 years there has been a significant decline and it is now very difficult to see one - it has been declared an endangered species. The shrikes in eastern Ontario belong to one of several subspecies of the Loggerhead Shrike, and the declining numbers mean that it may be impossible for this subspecies to survive.
This medium-sized songbird with a predatory lifestyle is mainly gray with black wings, white breast and a black mask that thinly extends across its forehead. Its strong hooked beak is its weapon of attack. Unlike hawks who use their powerful talons to capture prey, the shrike swoops down and strikes its prey with its strong beak, and often carries the prey with the beak as its talons are weak and designed for perching. Up to 20% of their prey are small vertebrates such as mice, snakes and small birds. The remaining 80% of their diet consists of insects. Loggerhead Shrikes from Ontario migrate south for the winter and return in early spring. Usually the male arrives first, and a display of prey impaled on spiny branches may assure courtship success - a male that is a successful hunter would make a good mate.
What has happened to cause this decline? Loss of and fragmentation of suitable habitat is one problem, as these birds require pastures or short grass meadows interspersed with shrubs and low trees. Hedgerows are an important part of the habitat requirement. The pastures and short grasses are needed to supply the insects, such as grasshoppers and crickets, which make up a major part of their diet. Spiny shrubs are used for food storage - the birds impale their prey on the spines after catching and killing it with their beaks. Low trees and shrubs are needed for nesting and places to perch as the birds watch for prey.
Habitat loss is only one part of the story, as the decline has occurred even faster than the loss of that habitat. Pesticides may affect the young birds, predation by larger birds and animals that raid nests may be a factor, and collisions with vehicles as the birds swoop across a road are also a problem.
Difficult to distinguish from its relative, the Northern Shrike, the time of the year is significant in identification. Just about the time the Loggerhead Shrike might be returning in the spring is the time the Northern Shrikes, which may have been here over the winter, will be heading to their breeding ground in the north. Then in the fall, just after the Loggerhead Shrikes have migrated south, the first of any Northern Shrikes will arrive. The Northern is slightly larger, and the black mask does not extend over the bill. In the fall the Northerns bill is usually paler than that of the Loggerhead. - but caution is needed to identify either one.
In an attempt to reintroduce this bird, several captive birds have been released in eastern Ontario - if you see a shrike, please call - it is important to see how this program is working. Do look closely to see if the bird is banded, and if so, what colour and in what sequence the bands are. I had a call last week from Bev Antoine, who had a shrike stunned by striking her window. It remained crouched on the ground long enough for her to get pictures, and I am looking forward to seeing them. Unfortunately Bev could not see its legs to see if it was banded, but she believes it was a Loggerhead.
