THE BIRDS OF NORTHERN THAILAND 33 



The paucity of records for the purple heron is no doubt due to the 

 absence of observers from its haunts during the rainy season. Gylden- 

 stolpe considered it fairly common on "the swamps of northern Siam" 

 (presumably Chiang Rai Province), sometimes in the ricefields, but 

 usually in swamps overgrown with reeds. I found it only in very small 

 numbers on the large marshes south of Chiang Mai from September 

 5 to November 12. On the lake at Phayao, August 24, 1929, I flushed 

 a single bird from a stand of tall reeds. 



It is a much wilder bird than the gray heron and is not likely to be 

 seen near human habitations. 



The purple heron is second in size only to the preceding species, from 

 which it may be readily distinguished by its having the head, neck, 

 and underparts largely rufous or buff; adults have the back and wings 

 gray, but immature specimens have the feathers of these parts 

 broadly margined with rufous. 



BUTORIDES STRIATUS AMURENSIS von Schrenck 



Amur Green Heron 



[Ardea (Butorides) veriscens] var. amurensis von Schkenck, Reise and Forschun- 

 gen in Amur-lande, vol. 1, pt. 2, 1S60, p. 441 (Amurland). 



The Amur green heron occurs in North Thailand as an uncommon 

 winter visitor. I have three specimens that may be attributed to this 

 northern form : An immature female from the foot of Doi Mae Kong 

 Ka, October 10, 1936, an adult female from Ban Muang Sum, De- 

 cember 27, 1936 ; and an adult male from the Mae Klang Waterfall, 

 February 11, 1937. The flattened wing of each of these birds measures 

 about 198 mm. 



All my examples were taken at mountain torrents, in wild and un- 

 inhabited country. 



The Amur green heron can be distinguished from the other races 

 occurring in our area only by its wing length, which ranges from 195 

 to 215 mm. 



BUTORIDES STRIATUS ACTOPHILUS Oberholser 



South China Green Heron 



Butorides javanicus actophilus Obeeholsek, Smithsonian Misc. Coll., vol. 60, No. 



7, 1912, p. 1 (North Pagi Island, off the western coast of Sumatra). 

 Butorides jaranica, Gyldenstolpe, Kungl. Svenska Vet.-Akad. Handl., 1916, p. 137 



(Tha Chomphu). 

 Butorides striatus javanica [partim], Gyldenstolpe, Ibis, 1920, p. 769 ("Northern 



districts"). 



Gyldenstolpe reported seeing three green herons along the Mae 

 Tha, near Tha Champhu, one of which, in fully adult plumage, was 

 collected, May 4, 1914. Since the wing of this specimen measured 186 

 mm., it must be attributed to this race. I place here also two unsexed, 



