by Hazel Wheeler,
Lead Biologist, Eastern Loggerhead Shrike Program
After years of working with shrike, I’ve noticed that nothing is ever as straightforward as I hope it to be. Around the WPC office, we’ve dubbed this the “Shrike Effect”; think of it like Murphy’s Law, but with more feathers. Others who have worked with shrike are probably also familiar with this phenomenon, though they may not realize how widespread it is. I’ve encountered it in so many large and small ways that I just accept it as part of working with the species.
For example, let’s say you want to catch a wild shrike. We do have great traps for it, but make sure you do everything you need with the bird the first time you catch it, because it’ll never be tricked by that trap again. For that matter, you best hope that a bird doesn’t see its mate trapped, because that could be enough to make it shy of the trap for the rest of it’s life. Shrike effect.
Or perhaps you want to radio-tag some birds to answer the burning questions about shrike migratory routes and wintering grounds. There are certainly tags that are can be used on a shrike, but make sure you get the body reinforced with hard plastic, and upgrade to a thicker, stronger antenna while you’re at it, otherwise the birds are likely to destroy the radio tags with their strong, raptor-like beaks. Shrike effect.
Incidentally, if you’re applying any kinds of bands to shrikes, either metal or plastic colour-bands, don’t kid yourself by thinking that they will take the typical aluminum bands used on most songbirds, or simple butt-end colour bands. No, shrikes need stiff, stainless steel bands (they can crush the aluminum), and you must use special “double-overlap” colour bands that wrap around themselves, making them more difficult to remove (which a shrike would surely do to a butt-end band). You should probably also melt the band to seal it to itself, because even these bands aren’t immune to a shrike’s prying beak. Shrike effect.
You may think that I am complaining, or that I don’t enjoy working with this species; I assure you, that isn’t the case. On the contrary, the Shrike Effect makes the loggerhead shrike a challenging and endlessly exciting bird to work with. One never knows what problems are going to arise that need to be solved, but you can be sure that things will always be interesting.
I shouldn’t have been surprised then, when I started digging in to our records to get some information on a very exciting milestone we passed this season, and hit a stumbling block. This year, we surpassed 1000 juveniles releases over the life of the recovery program, and I wanted to know exactly which bird was “Lucky 1000”. Turns out, there were two. It was the morning of July 20th when the 1000th bird left the release cage in Carden: a bird hatched at African Lion Safari, carrying a radio tag, and painted blue on it’s neck. This bird was followed immediately by another bird, ostensibly number 1001, and then…they both flew back in. About 10 minutes later, one of the clutch-mates of the first 1000th bird then left the release cage, so now this bird was the 1000th release… or 1002nd? In fact the first 1000th bird would go out and back in to the cage two more times before it was finally out and the cage was closed, so who can even keep track anymore? The Shrike Effect strikes again!