234 Recent Literature. [Aoril 



Stone and Rhoads on Birds from Northeastern Lower California. 1 — 

 A trip to the mouth of the Colorado River, made by Mr. Samuel N. Rhoads 

 in the early part of the year 1905, in the interest of the Academy of Natural 

 Sciences of Philadelphia, resulted in the acquisition of considerable col- 

 lections of mammals and birds, which are here reported upon by Mr. 

 Witmer Stone. The birds numbered 258 specimens, representing about 

 50 species. These are listed, with their localities and a transcript of 

 Mr. Rhoads 's field notes. A second annotated list of 58 species that were 

 observed, but not collected, completes this welcome addition to our 

 knowledge of the little known ornis of the delta region of the Rio Colorado. 

 — J. A. A. 



Thayer and Bangs on Birds from Panama. — Two papers (Nos. 2 and 

 3) have recently appeared relating to the results of the John E. Thayer 

 Expedition of 1904. The first 2 relates to the mammals and birds of the 

 Pearl Islands, Bay of Panama, collected by Mr. W. W. Brown on a second 

 visit to these islands in March and April, 1904. Previous to Mr. Brown's 

 first visit to these islands, in 1900. little was known of their natural history. 

 "On his first trip to the Pearl Islands Mr. Brown secured examples of forty- 

 two species of birds, only two of which were North American migrants. 

 On the present expedition he took representatives of ninety-two species. . . . 

 Thus the number of species of birds so far taken in the Pearl Islands is 

 ninety-four, of which thirty-three are North American migrants, and 

 sixty-one resident breeding birds of the islands. " Of the 33 North 

 American migrants 24 are passerine species and 9 are sandpipers and 

 plovers. 



Respecting a number of the species and subspecies there is much perti- 

 nent comment respecting their status and relationships. Of special inter- 

 est are the remarks on the Butorides virescens group. The Pearl Island 

 examples are found to be inseparable from the West-Indian B. v. maculata 

 (Bodd.), of which the B. v. brunnescens of authors appears to be merely 

 an inconstant color phase, both forms occurring in the Pearl Islands, 

 and between which, in the Pearl Island series "there is every stage of 

 intermediate coloring." It is further said: "After examining a very 

 large amount of material in this connection, we are forced to place very 

 little reliance on color as a character by which to distinguish the various 

 species. Seasonal difference in this respect is very great, individual 

 variation is also great, and in arid regions the bird bleaches out very 

 fast .... The subspecies maculata also has a rufous phase — the so-called 

 B. brunnescens — which thus far has been recorded from Cuba and the 



1 On a Collection of Birds and Mammals from the Colorado Delta, Lower California. 

 By Witmer Stone. With Field Notes by Samuel N. Rhoads. Proc. Acad. Nat. 

 Sei. Philadelphia, Sept.. 190.5, pp. 676-690. Dec. 6, 1905. 



-The Mammals and Birds of the Pearl Islands. Bay of Panama. By John E. 

 Thayer and Outran) Bangs. Bull. Mus. Comp. Zool., Vol. XLVI, No. 8, pp. 137-160. 

 Sept., 1905. Birds, pp. 140-160. 



