4 PEOCEEDINGS OF THE NATIONAL MUSEUM vol. 79 



BUTORIDES VIRESCENS VIRESCENS (Linnaeus) 



Little green heron 



Ardea virescens Linnaeus, Syst. Nat., ed. 10, vol. 1, 175S, p. 144. (Coast of 

 South Carolina.) 



A female taken on Swan Island April 19, 1929, is an example of 

 the green heron of North America, present here as a migrant. This 

 bird lacks the lighter edgings of the scapular feathers found in most 

 specimens of this race, but this is also true of numerous skins from 

 eastern North America; otherwise it is similar in color to them. It 

 measures as follows: Wing, 174.0; tail, 61.3; culmen, 61.0; tarsus, 

 49.3 mm. 



The identification of this bird brings up for consideration the 

 status of the supposed resident form of Swan Island currently 

 known as Butondes virescens saturatus Ridgway,^ represented by 

 two skins in the United States National Museum collected by Dr. 

 Charles H, Townsend on Swan Island, March 6 and 26, 1887. These 

 two skins are very dark, being in fact remarkably suggestive in gen- 

 eral appearance of Butorides v. frazari of Lower California. They 

 have the following dimensions: Wing, 177.0-178.0; tail, 59.9-62.7; 

 culmen, 61.0-61.2 ; and tarsus, 51.6-50.4 mm. 



Dr. Thomas Barbour writes that in his visits to Swan Island he 

 has not found the green heron nesting, and that George Nelson, 

 of the Museum of Comparative Zoology, who has been on the island 

 five times with an average stay of two months each time, likewise 

 failed to find these birds breeding. Further, it appears that there is 

 no suitable habitat for them, the few herons of this group that ap- 

 pear being migrants which have been seen flying in from the coast 

 of Honduras and these do not remain on the island long. The two 

 Townsend specimens have the dimensions of the B. v. virescens^ and, 

 although much darker than normal, are matched by occasional birds 

 from the eastern United States (notably by U. S. N. M. No. 77293, 

 from Hernando County, Fla.). The two collected by Doctor Town- 

 send are here identified as Butorides virescens virescens, so that the 

 name B. v. saturatus Ridgway will be listed in the synonymy of this 

 race. 



The bird secured, the only one observed on the island, alighted at 

 the landing place before the launch, and was shot almost immedi- 

 ately. Naturalists seldom have the good fortune to obtain so easily 

 material that is destined to straighten out moot questions based on 

 faulty specimens. Since for long periods there is no fresh water 

 on the island e^cept that collected in closed cisterns, it would seem 

 very improbable that green herons would attempt to breed there. 



^Butorides saturatus Ridgway, Proc. U. S. Nat. Mus., vol. 10, August 6, 1888, p. 577. 

 (Swan Island, Caribbean Sea.) 



