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March 01, 2007  Shrikes Alike On a recent trip to the dump I spotted a small-ish medium-sized bird perched on the power lines. At first I thought it was a Kestrel even though I knew that such a sighting was highly unlikely for February in the Cariboo. I approached could not make out the details of any bird other than a Kestrel, and then suddenly the bird metamorphosed into a Shrike. That’s right, the unidentified bird changed from a Kestrel-coloured and Kestrel-postured bird, to a Northern Shrike. What caused this radical switch? Was it self-hypnosis or self-delusion? Whatever it was, after making a positive identification, I sped away without stopping. But wait - how could I be so sure the bird was a Northern Shrike and not a Loggerhead Shrike? Could this delineation be made from a moving vehicle - to be honest, no. My hasty identification reminded me of a recent email from about a month ago. A lady retrieved a Shrike from the ground next to her house after apparently hitting a window. The bird was still alive so she took it indoors and put it in a cage to see if it would recover. Some time later she opened the cage outside and the bird flew off, but not before she had taken a few pictures with her digital camera. She wondered whether it was a Loggerhead Shrike or a Northern Shrike? I sent the lady an email strongly suggesting that it was a Northern Shrike. You might wonder how this was deduced, especially if you knew I had not yet seen the birds photograph. At this point I just went by my knowledge of the range of the Loggerhead, and Northern Shrikes. The Northern Shrike is not a rarity in the Cariboo, whereas the Loggerhead would certainly be noteworthy. A short time later the lady emailed back to say she had photos of the bird and would send them to me. Now it was time to do some investigating of my own. What were the visual differences between a Loggerhead and a northern Shrike? “Sibley’s Guide to Birds” lays the differences out quite succinctly. The Northern has a reduced mask (the mask being the black feathering through the eye and auricular area.) The Loggerhead has a wide extensive black mask both in front of and behind the eye. The bill size is also helpful. The bill of a Northern Shrike is prominent, looking longer than that of the fairly stubby-beaked Loggerhead. The Northern Shrike is only one inch longer than the Loggerhead but also has longer wings and tail giving it a larger appearance. Colouration is also helpful. The contrast between the gray and white feathering of the Northern Shrike is much reduced giving the darker Loggerhead a whiter looking throat with more contrast between back and chest. By the time I had studied the differences between the two Shrikes in several books, another email arrived, this one with several pictures of the Shrike. One of the pictures showed a very good shot of the head of the bird and the narrower mask suggested it was a Northern Shrike. I then asked my friend, essentially a non-birder for his opinion, showing him a picture of the differences in the mask pattern and then showing him the photo. He thought it looked like a Northern. I emailed the lady without giving her my opinion on the mystery bird’s identity, suggesting that she send the photos to Dick Cannings for his opinion. I never heard back from the lady and I assume she reached a conclusion about her Shrike. So here we are, another month gone by. Despite gaining some knowledge about the differences between our Shrike types, I still write off each Shrike I see as a Northern. I guess old generalities die hard. To e-mail Tom CLICK HERE To look at previous column CLICK HERE |
