THE BIRDS OF NORTHERN THAILAND 17 



4. Doi Ang Ka (Doi Inthanon), 8,400 feet, highest peak of the 

 Thanon Thong Chai range, situated about 35 miles west-southwest of 

 Chiang Mai ; it is the only known Thai locality for Siva singula, and 

 Aethopyga nipalensis angkanensis is probably endemic at its summit. 



5. Doi Langka (Doi Pha Cho), 6,601 feet, highest mountain of the 

 Khun Tan range, situated about 32 miles east-northeast of Chiang Mai. 



6. Doi Hua Mot, 6,047 feet, situated just northwest by north of Doi 

 Langka and forming part of the same complex. 



7. Doi Saket (Doi Lan), 5,958 feet, situated just southwest by south 

 of Doi Langka and forming part of the same complex. 



8. Doi Khun Tan (Doi Nga Chang) , 4,422 feet, a classical collecting 

 ground, situated about 29 miles southeast by south of Chiang Mai. 



9. Khao Phlung, a low mountain at the southern extremity of the 

 Eastern Phi Pan Nam range, situated about 20 miles south-southwest 

 of Muang Phrae. 



10. Phu Kha, 5,577 feet, mountain of the Phetchabun range, situ- 

 ated about 28 miles northeast of Muang Nan; it is the only known 

 Thai locality for numerous montane forms common to the eastward. 



CLIMATE 



Northern Thailand is subject to the typical monsoonal climate of 

 southeastern Asia, by which the prevailing winds, from October to 

 May, blow from the northeast and, during the rest of the year, from 

 the southwest. There are three distinct seasons — the cold weather, 

 the rains, and the hot weather. The first extends, at Chiang Mai, 

 from the middle of November to the middle of March; the third 

 from about the middle of March to the onset of the rains in May ; the 

 rains cover the remaining months. 



Meteorological observations made by Dr. A. F. G. Kerr at Chiang 

 Mai during the years 1909-1915 show the extreme minimum tempera- 

 ture of the air in the shade to have been 11.3° F. (February 8, 1911) 

 and the extreme maximum to have been 109.8° F. (April 1913). Of- 

 ficial observations made at the same place from 1927 to 1929 give the 

 former measurement as 48.56° F. (December 13, 1927), the latter as 

 103.60° F. (April 23, 1927). Official observations made there in the 

 years 1931-1932 give the mean minimum as 47.50° F. (December 16 

 and 17, 1932), the mean maximum as 104.90° F. (April 18, 1931). 



The following remarks are taken from the valuable contribution by 

 Kerr (Journ. Siam Soc, vol. 17, pt. 1, 1923, pp. 26-27) : 



The summit of Doi Sutep is 4500 feet (1350 metres) above the level of Chieng- 

 mai and is, naturally, very considerably cooler. 



The first meteorological observations taken on the top of Doi Sutep to be 

 published were those of Dr. C. C Hosseus who made temperature records there 

 for 4 days in the first half of December 1904. These observations, together with 

 others made by Dr. Hosseus elsewhere in Siam, were the subject of a paper by 

 Dr. Gerbing, "Das Klima von Siam und die Ergebnisse der von Dr. Hosseus 



