The Marsh Hawk 



No. 326 



Marsh Hawk 



A. O. U. No. 331. Circus cyaneus hudsonius (Linnaeus). 

 Description. — Adult male: Head and neck all around, chest, and upperparts 

 light bluish gray or ashy, the hind-head darker, with much partially concealed white, 

 and tinged with ochraceous; five outer primaries mostly black; upper tail-coverts 

 pure white, tail silvery gray, barred irregularly with blackish, the subterminal band 

 largest, tipped with whitish, the inner webs whitish or rusty-tinged; remaining under- 

 pays, including under side of wing (except terminal third of primaries), white, — the 

 belly, flanks and tibiae sparsely spotted or barred with bright rufous or pale dusk)-, 

 and the lining of the wing with a few dusky spots and bars: wings, tail, and shanks, 

 greatly lengthened; tip of wing formed by third and fourth primaries, wing when 

 folded falling an inch or more short of tail, and sometimes not reaching to end of feet. 

 Iris bright yellow; bill blackish; feet yellow; claws black. Adult female: Of different 

 coloring; upperparts dusky brown, the head and neck streaked and the lesser wing- 

 coverts and scapulars spotted or margined with cinnamon-rufous; longer upper tail- 

 coverts white, the shorter ones brown tipped with rufous; tail banded, silvery gray and 

 brownish dusky on central feathers, ochraceous tawny and blackish on remaining 

 pairs; underparts ochraceous or buffy, streaked broadly on the breast, and narrowly 

 on the belly with light brown or dusky. Immature: Similar to adult female but darker 

 — rich chocolate-brown above, and on sides of neck and cheeks; the underparts darker, 

 cinnamon-rufous, — the belly unmarked. Males show every gradation between im- 

 mature and adult plumage, and indeed the perfect adult male plumage is rarely found. 

 Adult male, length: 444.5-508 (17.50-20.00); wing 330.2-355.6 (13.00-14.00); tail 

 215.9-254 (8.50-10.00); bill from cere 16.5 (.65); tarsus 75 (2.95). Adult female, 

 length: 482.6-609.6 (19.00-24.00); wing 355.6-406.4 (14.00-16.00); tail 241.3-266.7 

 (9.50-10.50); bill 19. 1 (.75); tarsus 82.8 (3.26). 



Recognition Marks. — Crow size; white upper tail-coverts make the best field 

 mark; long tail; marsh-haunting habits. 



Nesting. — Nest: On the ground in marshes, of twigs and dry grasses or moss. 

 Eggs: 3-6) 8 of record, pale bluish white, usually unmarked but sometimes spotted 

 or blotched wifch pale rufous. Av. size, 45.2 x 35.6 (1.78 x 1.40). Season: April 

 10-May; one brood. 



Range of Circus cyaneus. — Europe, Siberia, and North America; south in winter 

 to China, India, northern Africa, West Indies, Colombia. 



Range of C. c. hudsonius. — Chiefly North America. Breeds from northeastern 

 Siberia, Alaska, northwestern Mackenzie, central Keewatin and Prince Edward Island 

 south to the southern border states. Winters from British Columbia, the Ohio Valley, 

 and New York, south to Cuba and northern South America. 



Distiibution in California. — Fairly common winter visitor at lower levels 

 throughout the State. Breeds commonly east of the Sierras south at least to Owens 

 Valley; and sparingly west of the Sierras at various valley points outside of the fog 

 belt, and south to San Diego. 



Authorities. — Gambel {Circus hudsonius), Jour. Acad. Nat. Sci. Phila., ser. 

 2, i., 1847, p. 28 (Calif.); Shufeldt, Bull. Nutt. Orn. Club, vol. vi., 1881, p. 197 (anat- 

 omy); Seton, Auk, vol. ii.. 1885, p. 22; Fisher, Hawks and Owls of the U. S., 1893, p. 26, 

 pi. 3 (food); Chandler, Univ. Calif. Publ. Zool., vol. xi., 1914, p. 329, pis. 



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