What to See Now: Shrikes

YOTB_stacked_KIn celebration of the Year of the Bird, we will highlight some of the birds and their behaviors that you can observe at certain times throughout the year.

 

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A pair of loggerhead shrikes from the Pawnee National Grasslands. All photos by © Wayne D. Lewis/CPW.

Driving down County Road 57 on the edge of the Pawnee National Grasslands, I saw a flurry of avian activity on a barbed-wire fence just ahead. I pulled over to see three of the four birds had moved off a bit, leaving one little bird sitting alone. Well, “sitting” isn’t quite right, because its legs were sticking out at odd angles. “Resting” isn’t correct either, because there wasn’t much peaceful about the scene. The small brownish bird was “stuck.” I edged my truck a few feet ahead to try and get a better idea what species I was looking at, but that didn’t help. It’s hard to identify a bird when it is missing its head.

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This small bird had fallen prey to a group of loggerhead shrikes.

It wasn’t really a mystery at all as to who was responsible: Three black-masked culprits impatiently waited nearby — two just one fence section down and another above on a powerline. They had clearly ignored the posted “no hunting” sign. I waited a few minutes, hoping they would return to the scene of the crime so my camera could catch them doing other naughty stuff, but they all flew off, apparently not wanting to be seen with the victim. I put my truck in drive and headed about 1,000 yards ahead before making a U-turn to sneak back and snap some damning photographic evidence, but I was too late. In that short time, the butchers had spirited the victim away.

While the identity of the victim will never be known, the perpetrators were instantly identified as shrikes. Shrikes are gray, black and white, robin-sized songbirds. I picture songbirds as cheerful, friendly, Disney-like birds — and maybe shrikes are, too, when they aren’t impaling grasshoppers, lizards, mice and small birds (sometimes when the prey is still alive) on thorns, spines and the barbs of barbed wire. Birds as big as meadowlarks and robins fall prey to shrikes, and even the occasional bat is eaten. Since shrikes lack talons like those of raptors, they stun or kill their prey with rapid blows from their poweful, hawk-like beaks and they will kill vertebrates by biting through their necks. Their impaled victims may be consumed right away or cached for later consumption. The cache also marks their territories and helps in attracting mates. Thus, butcher birds, one of the shrike’s nicknames, is a very accurate and appropriate description. They are also called thornbirds (they use thorns in hunting and also nest in thorny shrubs and trees) and blockheads (because many think their heads are too big for their bodies).

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Loggerhead shrikes search for their prey from vantage points such as trees and power lines.

Although I could easily ID the butchers, figuring out the type of shrike was harder. There are only two shrike species in North America and both can be found in our state. Colorado is home to northern shrikes, as well as their close relatives, loggerhead shrikes. Northern shrikes breed in Alaska and Canada, and their range dips down into northern Colorado. Loggerhead shrikes will nest in Colorado and can be found year-round in southern parts of the state. The Pawnee National Grasslands on the Eastern Plains is one of the areas where their ranges overlap. I reached out to Bruce Gill, an author and former biologist for Colorado Parks and Wildlife, and had him review my photos. “My guess is they are all loggerhead shrikes,” said Gill. “Northerns winter here, but don’t breed here. The ones in which the black does not extend across the bill are young of the year that have not yet developed adult plumage. Northerns breed far north along the Arctic Circle and Alaska.”

Gill, in his article “Butcher Bird” from the March/April 2013 issue of Colorado Outdoors magazine wrote: “Aside from contrasting distributions, several subtle physical characteristics distinguish adult loggerheads from northerns. At first glance, they look very much alike. But careful inspection reveals that northerns are slightly larger. The breast feathers of northerns are crisscrossed with very fine, wavy, contrasting dark lines. Breasts of adult loggerheads are mostly gray, lacking wavy lines.

“The black facemask of the loggerhead is broader than the northern’s and runs completely across the base of the beak whereas the narrower mask of the northern ends at the base of the beak. The hook on the upper mandible of the northern is also slightly longer than that of the loggerhead, but this characteristic is difficult to judge without side-by-side comparisons.

“Perhaps the most useful field-distinguishing characteristic from a distance is behavioral. The northern shrike has a habit of raising and lowering it’s long tail when perched, a gesture rarely used by the loggerhead.”

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Loggerhead shrike with the remains of a grasshopper. The author watched this bird remove the grasshopper’s legs and wings before swallowing it.

After some review, I determined that the culprits were loggerhead shrikes. However, the beauty of writing for blogs is that if I am proven wrong, I can quickly change the words on the screen.

“I’m not bad, I was born this way,” kept popping in my head as I thought about the scene I had witnessed. Bluebirds are often thought of as signs that happiness is on its way — unless you’re a cricket in its sights. Robins are welcome signs of spring — unless you’re a worm. Heck, even the little headless bird had been a very effective predator up until its untimely end. Don’t think of shrikes as avian Vlad the Impalers. Instead, think of them as the kindly butcher on the corner, just going about their business and providing for their families.

LOGGERHEAD SHRIKES


Wayne D. Lewis is the editor and art director of Colorado Outdoors magazine.

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