64 Zoology of Colorado 



canadensis) is the common wild goose; it breeds in the mountains. 

 There is a smaller subspecies, with only 16 (instead of 18 to 20) 

 tail-feathers, known as B. canadensis hutchinsi of Richardson. 

 It appears to be uncommon in Colorado, but is perhaps not always 

 distinguished from typical canadensis. 



Swans are very rare in our State, but the Whistling Swan 

 (Olor columbianus of Ord) and the Trumpeter Swan (0. buccinator 

 of Richardson) are occasionally observed. The former has, the 

 latter lacks, a yellow spot on the bill in front of the eye. 



HERODIONES 



These have the lower part of the thighs naked (an adaptation 

 to their wading habits), as in the Paludicolae and Limicolae. 

 But they differ by having the hind toe long, and inserted nearly 

 at a level with the others, and the loreal or orbital regions, or 

 both, naked. We have the families Plataleidae (for the rare 

 Roseate Spoonbill, Ajaja ajaja), Ibididae or Threskiornithidae 

 (Ibises), Ciconiidae (the stork family, including the so-called 

 Wood Ibis, Mycteriaamer icana, which has occurred as a straggler) 

 and Ardeidae (herons, egrets and bitterns). Of the four species 

 of Ibis, the white Guar a alba and the scarlet G. rubra are extremely 

 rare stragglers. The Glossy Ibis (Plegadis autumnalis) is also an 

 accidental visitor, but the White-faced Glossy Ibis (P. guarauna) 

 is a summer resident, breeding up to about 7,500 feet. It has the 

 feathers surrounding the face white. All these species of ibis 

 were described by Linnaeus in the eighteenth century. The 

 Ardeidae, with long and straight bill, are numerous in Colorado. 

 The two genera of bitterns have the tail feathers reduced to ten, 

 short and soft. The American Bittern (Botaurus lentiginosus of 

 Montagu) has conspicuously striped plumage; it is rather common 

 during the summer months. It was originally described by Col. 

 Montagu in 1813 as a new British bird, an individual having 

 somehow turned up in Dorsetshire. The Least Bittern, (Ixobry- 

 chus exilis) is only about half as large, and has the back black or 

 brown. 1 1 is a rare summer resident. The Black-crowned Night 

 Heron {Nycticorax nycticorax naevius) and the Yellow-crowned 

 Night Heron (N. violaceus) have a comparatively short and stout 

 bill, and in breeding plumage a few very long white plumes from 

 the back of the head. In the former the crown is black, in the 



