Monday, November 24, 2014

A "Sharp-eye" on the Bird Feeders

I returned home from church Sunday and glanced out the kitchen window to see if anything other than House Finches, House Sparrows, and Dark-eyed Juncos was enjoying the food I put in the feeders. I didn't see a single bird below, on, or above the three feeding stations. There was an eery silence around the feeders and throughout the yard.  A loaded-yet-abandoned bird feeder on a wintry day in our yard has proven on previous occasions to be an indication that a bird predator is near. And I'm not talking about a neighborhood cat. The birds learn how to work around the cats, but they hide for their lives when one of their own is the predator. I'm talking about a bird-eating hawk.

Cooper's and Sharp-shinned Hawks are notorious for preying on smaller birds around yard feeders during the winter months. A glance around the perimeter of our yard revealed the reason for Sunday's silence. A juvenile Sharp-shinned Hawk, or Sharpie as many call them, was perched on the fence and was keeping a "sharp eye" on the feeders and the densely wooded shrubs where the tweety birds were hiding and pretending not to exist. My wife was not surprised when I lost complete interest in whatever I was supposed to be doing and dashed into my office to retrieve my camera. She's familiar with my bird conniptions. I ran to the garage, propped open the side door and focused as best as I could on the hawk while wind and snow were blowing between us.

This hawk was intent on eating. I could see that its crop was empty and I watched it give piercing glances in all directions as I was composing and capturing images. The images below show how the hawk turned its carnivorous glances from one hiding spot to another. It was determining its best line of approach to lunch.

Juvenile Sharp-shinned Hawk Hunting for Prey Near Yard Feeder, Utah County, UT

Juvenile Sharp-shinned Hawk Hunting for Prey Near Yard Feeder, Utah County, UT

Juvenile Sharp-shinned Hawk Hunting for Prey Near Yard Feeder, Utah County, UT

Juvenile Sharp-shinned Hawk Hunting for Prey Near Yard Feeder, Utah County, UT
The hawk eventually turned and flew to a concealed perch in a neighbor's tree. These hawks will often perch in a concealed location and wait for birds to forget about their presence so they can make a quick and effective ambush.

Separating Juvenile Sharp-shinned and Cooper's Hawks

The image above is a good one for identifying the hawk as a juvenile Sharp-shinned. The brown upper side, streaked nape, and yellow eyes are typical for a juvenile. The back will become gray to slate-blue when it becomes and adult. The head is small, relative to the hefty chest, and smoothly rounded from crown to nape. The similar looking Cooper's Hawk presents a larger and blockier looking head relative to its slender or tubular body. The chest for a juvenile Sharp-shinned Hawk has a streaked rather than the barred appearance seen on adults. The streaking for a juvenile Sharp-shinned is more coarse or blotchy compared to the more finely streaked Cooper's Hawk. Cooper's Hawks have a more brown looking streaking on the chest where the Sharp-shinned has more of a rufous or orange color. The markings on the juvenile sharp-shinned are also thicker around the flanks than they are at the top of the chest.

Juvenile Cooper's Hawk in Las Vegas, NV
I'll share an image of a juvenile Cooper's hawk I photographed in Las Vegas this summer to illustrate the traits I've mentioned. There is variability and exceptions occur with these bird species, but the images I'm sharing are typical. This young Cooper's Hawk shows the blocky head, slender body, and fine brown streaking on the chest and belly. The streaking isn't as thick and blotchy in the flanks compared to Sharp-shinned. I think I have a good feel for these hawks and then I run across some that make me scratch my head when trying to separate the two species. Sometimes I find it easier to distinguish them in the field and harder with a photo because photos are one-dimensional. Seeing a bird in the field reveals multiple dimensions including shape, plumage, behavior, etc. It often takes the sum of traits rather than a single trait shown in a photo to accurately identify a bird species.

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