Jan 9, 2010

Our Accipiters

They are the hawks that also frequent our bird feeders; only it’s not birdseed they’re looking for.  They are visiting our feeders to eat the birds we have become so attached to… our cardinals, robins, wrens, goldfinches and nuthatches.  They are Accipiters.


With their characteristic long tails and short rounded wing, these woodland hawks fly through the trees like fighter pilots.  Their wings allow them to quickly dodge around and between trees and branches.  The long tail aids in braking and making fast turns.  And though they’ll also eat small mammals, snakes and lizards, other birds are their primary food choice.  Our bird feeders, with dense concentrations of “feeder birds” make for easy pickins’ for these handsome and eloquent-looking hawks.  It’s a spectacle worth observing.


Debbie Macke of Park Hills has been watching and feeding birds for most of her 60-plus years.  She wasn’t prepared though as she watched events unfold at her home near Devou Park last winter.  At first all seemed well at her well-stocked feeders.  Then all of a sudden her birds seemingly disappeared and the few she could see were frozen in place, obviously hiding.  Above, in a tree outside her family room window was a hawk Debbie had never seen before, eyeing her feeders like a high school football player at KFC.  It wasn’t long before a wayward starling was nabbed in flight by the hawk in her side yard.  “Unbelievable,” said Debbie.  “It happened so quickly.”  A search in her Peterson Field Guide revealed the culprit, a Sharp-shinned Hawk, one of three Accipiters native to North America


Sharp-shinned Hawks (Accipiter striatus), or Sharpies, are the smallest of our Accipiters, about the size of a Blue jay.  They are the most widely distributed Accipiter in North America, inhabiting virtually all of North America into the Caribbean, Central and South America.  Mature sharpies have slate colored upper parts with a dark crown.  Their under parts are white with brown bars on the breast.  The tail is square-tipped with 3 to 5 dark stripes.


Sharpies are opportunistic hunters.  They’ll hunt from a perch and dart from hiding to catch prey, with birds comprising 90 percent of their diet.  They pluck their fowl before dining, and usually get sufficient miosture from their prey and drink very little water otherwise. 


Cooper’s Hawks (Accipiter cooperii), or Coops, are our medium sized Accipiter and are about the size of a crow.  They look very similar to Sharp-shinned Hawks and the two are easily confused.  The crown of the Coop is darker than the Sharpie, and the tail is rounded at the tip while the Sharpie’s tail is more squared.  Their diets and hunting style are similar, with birds making up the bulk of their diet.  Coops eat an extraordinary amount of food relative to their size, up to 12%of their body weight per day.  In human terms, it’s like a 200-pound person eating 24 pounds of food daily.  The Cooper’s Hawk was named after naturalist William Cooper, a founder of the New York Lyceum of Natural History in 1817, which later became the New York Academy of Sciences.

The Northern Goshawk (Accipiter gentilis) is our largest Accipiter, about the size of a Red-tail Hawk.  This bird not only inhabits North America, but is also found across Europe and Asia.   Because of its speed and fearless demeanor, it has for centuries been a favorite of falconers.  Adults are slate gray above and barred gray below with pronounced dark eye lines and crown. 


The common name “goshawk” is derived from “goose hawk,” and deservedly so as ducks are one of this birds favorite foods.  Goshawks though are not nearly as dependent on birds as a food source as are Coops and Sharpies.  In the Northern Boreal Forest they are so reliant on Snowshoe Hares that they will not even reproduce unless the hare population is abundant.  A more northern species, Goshawks are only rarely seen in our area.


All Accipiters are reverse dimorphic, meaning that females are considerably larger than males.  A female Sharp-shinned Hawk is very similar in size and coloring to a male Cooper’s Hawk.  The immature birds of all three species are brown above and lightly barred below.  Proper identification is tricky; a good pair of binoculars and field guide is almost essential. 


Our Accipiters are long-lived birds, and can live from 15 to 20 years in the wild.  Like so many other birds, they were severely impacted by the pesticide DDT.   Fortunately, DDT was banned in 1972 and all have made healthy comebacks.  Habitat loss is now their biggest threat.


Naturalist and artist John James Audubon painted and described all three of these fascinating birds.  His comments ring every bit as true now as they did in the early 1800’s…


“While in search of prey, the Sharp-shinned Hawk passes over the country, now at a moderate height, now close over the land, in so swift a manner that, although your eye has marked it, you feel surprised that the very next moment is has dashed off and is far away.   The food of this Hawk consists chiefly of birds of various sizes, from the smallest of our warblers to the Passenger Pigeon…”


“The marauder (Cooper’s Hawk) frequently attacks birds far superior to itself in weight, and sometimes possessed of courage equal to its own.  This species frequently kills and eats the Grouse commonly called the Pheasant.  Partridges and young hares are also favourite dainties.  It also follows the Wild Pigeons in their migrations, and always causes fear and confusion in their ranks.”


“I have found them (Northern Goshawk) rather abundant in the lower parts of Kentucky and Indiana…They caught Mallards with ease, and after killing them turned them belly upwards, and ate only the flesh of the breast, pulling the feathers with great neatness, and throwing them round the bird, as if it had been plucked by the hand of man.”


Contact Gayle at gaylepille@yahoo.com


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