256 ANIMAL LIFE IN THE YO SEMITE 



The Harlequin Duck, strange to say, belongs to the class of sea ducks, 

 and spends the winter exclusively along the roughest, surf-beaten ocean 

 shores, such as, for instance, those around Point Reyes. Curiously, the 

 birds have never been observed at any point between their mountain and 

 seacoast haunts. 



American Bittern. Botaurus lentiginosus (Montagu) 



Field characters. — Large size (height, standing, about 22 inches) ; heron-like build, 

 but much smaller than Great Blue Heron. Plumage streaked light and dark rusty 

 brown, closely resembling dead tules in general effect. 



Occurrence. — Casual transient. Individuals seen by Donald D. McLean along Smith 

 Creek, east of Coulterville, during the fall months. 



The American Bittern, which is typically a bird of the tule swamps, 

 does not often venture out into the open as does the Great Blue Heron. 

 Its whole plumage blends so well in color with the dry tules in which it 

 lives that it is ordinarily overlooked, save when flushed. Then it flies 

 in typical heron fashion, with head drawn in, legs trailing behind, and 

 broad wings slowly beating, to soon drop again into the marsh vegetation. 

 This bird will not be found with regularity in the Yosemite section, because 

 of the scarcity there of suitable cover. 



Least Bittern. Ixobrychus exilis exilis (Gmelin) 



Field characters. — Our smallest Heron; little larger than Killdeer; bill and legs 

 long and slender. Male: Top of head and whole back greenish black; flight feathers 

 dull black; sides of neck reddish brown; whole under surface mixed white and light 

 tan color. Female: similar, but top of head and back dark reddish brown. 



Occurrence. — One instance : a male obtained at a pond at mouth of Kush Creek, Mono 

 Lake, June 3, 1916. Frequents tule marshes. 



The single specimen of this elusive species obtained by our party, as 

 detailed above, was the only one seen anywhere. Its weight was 66 grams 

 (about 2.3 ounces). It is of interest to compare this weight with the 

 475 grams (about 17 ounces) of the American Bittern and the 1530 grams 

 (3.4 pounds) of the Great Blue Heron. In other words, the Great Blue 

 Heron is 23 times the size of its smallest relative, the Least Bittern. 



Great Blue Herons. Ardea herodias Linnaeus'® 



Field characters. — Tallest bird occurring regularly in the Yosemite region (stands 

 3 feet high or more) ; general form slender ; neck and legs very long. General color 

 slaty blue; head marked with white and black; neck brownish; pattern of under surface 



18 Two races of this species occur in the Yosemite region, a darker form, the Cali- 

 fornia Great Blue Heron (Ardea herodias hyperonca Oberholser), which ranges from the 

 plains of the San Joaquin eastward at least to Yosemite ; and a paler Great Basin form, 

 the Pallid Great Blue Heron (Ardea herodias treganmi Court), which is found about 

 Mono Lake and strays westward at least to Tuolumne Meadows. These two forms 

 cannot be distinguished except as specimens in hand. 



