106 RUDOLF SÖDERBERG, STUDIES OF THE BIRDS IN NORTH WEST AUSTRALIA. 
the latter are dark greyish, having no olive tint at all, the head being brown 
grey with hardly any olive. In the female the olive colour is present on head, 
throat and breast, and a broad yellow-olive stripe is formed under the region of the 
eye. Belly very light. 
Ecological. — This form, the nest of which I possibly also found (see page 26) 
was seen at Mowla Downs and in Dampier land, where I observed it on several oc- 
casions. Some birds that were examined had eaten small black beetles. 
Ptilotis sonora decipiens MATE. 
Math. handl. n:r 772. 2 29 ad. Derby, Kimb. !7/:0 1910, moult. 
Moulting. — Both the specimens are in moulting. The one in an advanced 
stage, so that back and breast are nearly complete, and in the tail many feathers 
are new. The other specimen has a very worn plumage and has not really begun 
its monulting. 
It is noteworthy that the specimen that has not yet moulted, has considerably 
more lightbrown-colour on the back and head, the new plumage being more greyish 
brown with olive gloss. 
Ecological. — This species was common both on the continent and at Sunday 
Island. The singing of the bird was high and clear, reminding one a little of that 
of our thrushes. 
Ptilotis flavescens flavescens GouLbD. 
Math. handl. n:r 788. 3 SS ad. Derby, Kimb. !$/0, worn dress, slightly moulting; one wing-feather dropped 
and grown out; 2/10, worn dress; ?9/:0 1910, the back moulted, the breast in moult.; 5 SS ad., 2 ad. Noon- 
canbah, Fitzroy r. 109/;>, moult.; ?3/12, nearly fully-moulted, wing- and tail-feathers growing out; 7/12 1910, nearly 
fully-moulted; ?/, the back-part and the tail in moult., otherwise fully-moulted; ?/1 breast, tail and wing-feathers 
in moult. the rest fully-moulted; !'/2> nearly fully-monlted; $2 ad. !5/5 Meda, new plumage; 2 29 ad., I ad. Beagle 
bay; !2/7 the breast in moult.; 17/7 tail-feathers grown out; "2/7 1911, slight moult. in the breast. 
Variants. — Specimens '!'/10 and '!?/12 (these may be younger birds), ?/12 
and ”/1 have the colour of the bill much lighter than the others. With regard 
to specimen no. 2 I have noted: »The bill apparently yellow in distinction from 
specimen no. 1. Only the point is blackish>. The worn specimens (shortly before 
the summer-moulting) have, especially on the back of the neck, a lightbrown or buff 
tint. This is very clearly the case with nos. 2 and 4, these being younger birds, I 
suppose. The colour of the bill bright yellowish. The female smaller than the male. 
Moulting. — Moulting birds all the summer until far into Febr. The October 
specimens have very worn plumage; the moulting has slightly begun in two birds. 
Wing-feathers also grown out. The December specimens generally in moulting. The 
feathers of the body change a little before the tail- and wing-feathers are dropped. 
One specimen in May is not in moulting. All the other three July specimen (Beagle 
bay) show some moulting (partial). One has even obtained new tail-feathers. 
