The Cooper Hawks 



the birdman; and in return for the few sharp glances he bends downward, 

 affords a full view of his short, rounded wings and his long, rounded tail. 

 One is impressed rather with the bird's ease and nonchalance than with 

 its swiftness in flight; but it is a master at checking and tacking, so that 

 few of the smaller birds are a match for it in the open air, and not all 

 of them in the mazes of the forest, which the hawk threads relentlessly. 



In nesting, the bird sometimes avails itself of an old crow's nest, 

 taking pains to fill up the nesting hollow with twigs, and adding a few 

 twigs yearly in a desultory way. Oftener, however, the bird is his own 

 architect — and contractor. He, or he and she, construct a very substantial 

 platform of slender twigs, lined, or at least marked, with some sort of 

 greenery. This is placed at any height, but usually, if the situation allows, 

 well up. Alders, willows, oaks, sycamores, any tree that offers will do, so 

 the site be secluded and the surrounding cover as dense as possible. In the 

 evergreen stretch, young fir trees are almost invariably utilized, and nests 

 are placed at a height of 60 or 80 feet. 



Nesting is in April or May, according to altitude, and second sets may 

 or may not be laid in June. The eggs, three or four, or, rarely, five in num- 

 ber (in the West), may be conveniently described as "hawk-egg color, "- 

 chalky white with a bluish tinge, too subtle for precise nomenclature, un- 

 marked, or rarely, spotted and blotched with cinnamon or sayal brown. 

 The incubation period is said by Major Bendire to be 24 days (it is prob- 

 ably much longer). The parents are aggressive to the point of offering 

 personal violence, or else wary to the point of punctilious absence — 

 according to the "discipline" they have received. The successful rearing 

 of a family of four Cooper Hawks, to speak only of the month or there- 

 abouts which they spend in the nest, costs the bird world approximately 

 750 lives. A year's board-and-keep for a single Cooper Hawk represents 

 the tidy sum of 2920 sparrows, not to mention much other refreshment. 

 If we allow a single bird per section in California, assigning thus 72 square 

 miles on the average for the support of a single pair of Cooper Hawks, we 

 shall have an annual meat bill for Accipiter cooperi of 12,652,360 bird 

 units. A rather expensive boarder! 



The Cooper Hawk population of California is undoubtedly aug- 

 mented in winter by accessions from the North, and the lowlands receive 

 correspondingly the discharge of the upper levels. Yet it is quite probable 

 that the lowland population is about stationary. 



Regrettably, neither time nor space permit me to expand the claim 

 that the Cooper Hawks of southern California belong to a southern race, 

 A. c. mexicanus. Suffice to say that the evidence of the egg eloquently 

 supports this view, for southern-taken eggs average decidedly smaller 

 than those taken further north. 



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