534 
Birds of Celebes: Motaeillidae. 
The Eastern and Western forms of M. flava are equally entitled to sub- 
specific distinction in virtue of the difference in the hind claw; if* so separated 
the Eastern form would have to bear the name M. flava flaveola (Pall.). It is 
also extremely doubtful whether M. borealis and M. cinereicapilla Savi do not 
intergrade with the forms of M. flava. 
The Blue-headed Yellow Wagtail is a winter visitor to Celebes, though 
individuals remain there, apparently, all the year. Meyer met with it at 
Limbotto in July, and the adult male described supra was shot by Platen on 
June 16*^ 1878, in South Celebes. Everett mentions it as a regular winter 
migrant found throughout the N. W. coast of Borneo from September to May, 
and Whitehead saw it in “thousands” on the Tampassuk plains. During his 
expedition to Palawan the latter naturalist first saw it on 1 3*^ September, “when 
the vangmard passed in a south-westerly direction. In October they were still 
migrating in hundreds, but were mostly young birds” (16). M. flava came on 
board Meyen’s ship on the China Sea between China and Luzon (3, 4), and 
Mr. Finn (Ibis 1893, 225) mentions specimens, which he took for this species, 
as having settled on his steamer in the Mediterranean and Red Sea, while 
Mr. Hartert (a %) writes that specimens accompanied his steamer from the 
south coast of Arabia all the way to Acheen Head in Sumatra, so making the 
journey from west to east. In Pegu Mr. Oates found it to be rather a rare 
winter visitor. It passes through Central China, according to Mr. Styan (20), 
on migration in spring and autumn, but the Abbe David (a 2), whose obser- 
vations were made more in the northern part of the country, writes that it is 
common in China from spring to the end of autumn and particularly abundant 
in summer in Mongolia. It was not known to Seebohm (18) from Japan 
in 1890. 
It breeds in Kamtschatka where Taczanowski (a 7) describes it as not 
rare, but in Dauria Dybowski and Godlewski found it rather scarce. 
That some individuals of M. flava sometimes remain behind in their winter 
quarters is an interesting fact, though by no means an isolated one, and tends 
to prove that migration is not the effect of a blind irresistable impulse driving 
the bird on its alternate northward and southward journeys. 
221. MOTACILLA BOAKULA L. 
Grey Wagtail. 
,Two subspecific forms of the Grey Wagtail have so far been distinguished: 
1. The typical Motacilla boarula. 
a. Motacilla boarula (1) Linn., Mant. Plant. 1771, 527; (II) Gould, B. Eur. 1837, U, pi. 147. 
b. Motacilla sulphurea (1) Beclist., Naturg. Deutschl. 1807, HI, 459; (II) Naum., Vog. 
Deutschl. in, 824, t. 87 (1823); (.3) Newton, ed. Yarr. Br. B. 1873, I, 552; (4) 
Seek, Br. B. H, 1884, 203, pt. 
