532 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.43. 



Barbara Islands, California. To all of these institutions and indi- 

 viduals the writer wishes to express his obligation; also particularly 

 to Dr. Charles W. Richmond, the Assistant Curator of Birds in the 

 United States National Museum. 



The geographical range of Ardea herodias, as a species, extends 

 from southern Alaska and southern Canada, south through the 

 United States, Mexico, Central America, and the West Indies, to 

 northern South America, Although the available specimens from 

 some regions are few, there are apparently 10 recognizable races, 

 which subsequent investigation of abundant material may increase 

 by one or two. There are already six current forms, so that the pres- 

 ent investigation has resulted in the addition of four. The great 

 blue heron lives in almost any sort of country, forest or open, desert 

 or humid, if it has only the one requisite — water, from which it 

 obtains the major portion of its food. It breeds usually in colonies, 

 in trees or on the ground, and doubtless wanders far in search of 

 food, along the shores, shallows, and muddy banks of streams, 

 lagoons, and ponds, which are its favorite hunting grounds. Too 

 little is known of the details of distribution to permit a very decided 

 opinion on the life zone affinities of the various subspecies, but from 

 what we Icnow it does not appear that, except in a general way,they 

 conform very well to accepted zonal boundaries, as suitable nesting 

 sites are often the controlling influence. Conseq.uently, the attempt 

 to give them some such status must be taken with proper reservation. 

 Most of the races are more or less migratory, though some of this 

 movement is doubtless the well-known presestival and postsestival 

 wandering in which herons so commonly indulge. Two forms, Ardea 

 herodias cognata, and Ardea herodias oligista, ^ with probably also Ardea 

 herodias sanctilucae, and possibly ^4 reject herodias fannini, are sedentary, 

 or at least do not pass beyond their ascribed breeding areas. As in so 

 many other wide-ranging species, some of the far-separated subspecies 

 resemble each other much more than they do the adjacent forms with 

 which they must bear nmch closer phylogentic relationship. For 

 instance, the West Indian race, Ardea herodias adoxa,^ is much more 

 nearly like Ardea herodias herodias than like the intervening Ardea 

 herodias wardi; Ardea herodias cognata, from the Galapagos Islands, 

 very much more closely resembles Ardea herodias treganzai, from the 

 southwestern United States, than it does Ardea herodias lessonii ^ 

 from Mexico; Ardea herodias oligista ^ and Ardea herodias hyperonca * 

 are both much more like Ardea herodias herodias from the eastern 

 United States than like the interposed Ardea herodias treganzai; 

 while the Mexican Ardea herodias lessonii^ is closest in appearance 

 to Ardea herodias fannini of British Columbia, instead of to the 



» See p. 553. 2 See p. 544. » See p. 555. * See p. 550. 



