A blur of motion, a flurry of feathers and then its gone! A
Sharp-shinned hawk has struck again. This tiny, fast and highly acrobatic flier
is the smallest hawk in North America. The general make-up of this diminutive accipiter is noted as “long legs, short
wings, and very long tails, which they use for navigating their deep-woods
homes at top speed in pursuit of songbirds and mice.” In the image of the
Sharpie here with the American robin in it’s clutches the raptor appeared to
have used my presence as a distraction and when the robin bolted from me the
hawk boldly nailed it within twenty feet of where I was standing. For a moment
I was as surprised as the robin, though not mortally so.
Sharp-shinned like many other hawks declined during the DDT
pesticide years but rebounded after the insecticidal chemical was banned. The
populations of Sharp-shinned Hawk have remained stable with some growth from the
early 1970s according to data from the North American Breeding Bird Survey. Still
scientists have little data on their
nesting success given the solitary and elusive nature of these small hawks in
their deep-forest breeding sites. Populations estimates from annual migration
counts puts breeding pairs of these birds near 700,000.
Sharp-shinned Hawks are birds of the forest and prefer a
dense, closed canopy, for breeding and nesting. In our highlands regions these
birds favor conifers forests but intermix throughout the river and stream
valleys in cottonwoods and aspens. The habitat range of elevations varies from
sea level to near timberline.
Some interesting points regarding this species; while atypical in the general world of avians
(though common amongst raptors) female Sharp-shinned Hawks exceed the size and
weight of males by about 1/3. This size difference plays a role in the raising
of the hatchlings as it is the male that feeds the nestlings, given the smaller
size of prey captured and the female that feeds the same young in their larger
juvenile stage. And uniquely the male sharpie bites off and eats the head of
prey before sharing the meal. Another
behavioral trait of some raptors found in adult Sharp-shinned Hawks is how they
continue to feed the juveniles for several weeks after they have fledged. The
parents deliver dead prey into the nest leaving the young to squabble and consume.
Later the parent approaches and calls triggering the fledglings to rise to grab
prey out of its parent’s claws. As the fledglings develop flight skills, the
parents cease feeding at the nest and force the juveniles to pursue in flight
with rewards of morsels. In such ways the skills of an aerial predator are
achieved. 
Its estimated that the Sharp-shinned Hawk’s diet is 90% songbirds.
As pictured here birds the size of robins, warblers, sparrows, and thrushes are
the most frequent prey. Bigger birds such as quail, doves, swifts, woodpeckers and
the like are not completely safe from this little raptor. Adding to the diet
are mice, voles, chipmunks and grasshoppers.
To observe these unique hawks closely watch the forest edge.
Keep a sharp eye out for a dash of feathers flying fast and low, following the
contour of the ground. Look into the foliage for that poised shape awaiting to
spring on their prey. And
don’t be too surprised if a Sharpie whizzes past your ear and takes down
another bird in flight. It does happen…
X
No comments:
Post a Comment