Page 24 - Black Range Naturalist, Vol. 2, No. 1
P. 24

  An immature Common black hawk, one of two that fledged on the ranch in 2018.
  A mature Common black hawk hunting for one of its preferred targets: large red crayfish. (Originial photo right, detail left.)
It’s Not About Species
 By Bob Barnes



It is not all about species: we are lucky enough to be able to study several bird subspecies in our area. The groups of Dark- eyed Junco (which we regularly
track) are the most notable
example. Another example is
the White-crowned Sparrow.
The common subspecies in
our area is Zonotrichia
leucophrys gambelii. This
sparrow of the west Taiga
migrates to our area during
the winter. Note the white
lores on the bird in the
photograph in the left column.
(Lores are basically the area between the eye and the bill of a bird.) Lore color is a major distinguishing characteristic between the various subspecies of White-crowns. (There are five.)
Zonotrichia leucophrys oriantha, the sparrow of the interior west of the United States and Canada (photo right column), migrates to Mexico during the winter from its breeding range in the mountains of the interior west. During passage, it is regularly found in our yard in Hillsboro, where both of these photographs were taken.
Intergrades occur between the subspecies of White-crowns where their ranges overlap. Birds that breed in the Taiga show strong clinal differences between the populations of the east and west (light lores to the west and dark to the east). Some birds from the
eastern Taiga winter in central Texas, and it is possible that birds from the eastern Taiga, which show dark lores, might be found in this area during winter.
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