Friday, November 24, 2006

Northern Shrike at the Great Swamp

Photo by Marek Szczepanek (via Wikipedia)

For the past few days I have been in New Jersey visiting family. This afternoon I went with them to the Great Swamp, a National Wildlife Refuge a bit south of Morristown. We all have a love for the outdoors, though not all are equally interested in birds.

At our last stop, the heronry overlook on Pleasant Plains Road, we spotted the northern shrike that has been hanging around there recently. It was in the field across the road from the overlook, closer to the manmade pond than to the overlook itself. We were able to watch it for some time, as it perched out in the open on top of some small shrubs.

Northern shrikes have a color pattern similar to mockingbirds, with the exception of a black mask and black flight feathers. The tail is proportionately shorter than a mockingbird's, and the bill is short, thick, and hooked. This shrike sat upright - almost like a flycatcher - and swooped frequently to the ground in pursuit of prey. I am not sure if any of its sallies were successful; if they were, the prey must have been small because I could not see anything in its bill. It is much easier to recognize a shrike than I originally thought it would be.

Shrikes have a reputation for cruelty, which is not entirely deserved. (The genus name Lanius means "butcher.") Partly the reputation stems from shrikes' habit of impaling prey on thorns or barbed wire fences, as in the photograph above. They do this in some cases to hold larger prey in place while they eat it, and at other times to save food for later in case of scarcity. Though they are small birds, shrikes will kill small rodents and small birds for food. I imagine that such catches are ugly scenes, since a shrike's feet and bill are not powerful enough to render a swift blow.

In any case, this was my first sighting of this unusual species. Apparently there have been shrike sightings at this location for the past few years, and the local birders seemed to be well aware of its presence. Despite that, northern shrikes are somewhat rare for New Jersey, and even rarer around D.C. Most breed in Alaska and northern Canada, and few make it this far south for the winter. It was a great bird and a great day to be out.

Update: A photo of the Great Swamp bird is available here.