32 THE BIRDS OF AUSTRALIA 
4. Cave Owl Tyto novce-hollandice troughtoni sub.-sp. nov. 
troughtoni— Ellis Le G. Troughton, Mammologist, Australian Museum, 
Sydney. 
distribution. Nullarbor Plain (South Australia). 
notes. Usually singly or in pairs, frequenting the Nullarbor Plain. 
It roosts and nests in blow-holes and underground caves, venturing 
forth at night in search of prey. Food: small lizards, small mammals, 
and rodents. 
nest. In a blow-hole, eggs deposited on the bare sand. 
eggs. Two, white and oval, texture of shell coarse, with a faint 
gloss. Eggs taken on the Nullarbor Plains, in November 1931. 
description. Type, adult female, collected at Ooldca, East-West 
Line, South Australia, by Messrs Troughton and Wright on 16 October 
1921, Registered Number 026568, Australian Museum, Sydney. Differs 
from the typical Masked Owl (Tyto novce-hollandicc) in its smaller size, 
lighter coloration on the back, and in having fewer spots on the under¬ 
parts. Measurements: total length, 460 mm.; wing, 326; oilmen, 26; 
tail, 161; tarsus, 75. 
Females of the Masked Owl are noticeably larger and darker than 
the males; the type of the Cave Owl, however, which is a female, is 
comparable to an average-sized male of the Masked Owl. 
5. Tasmanian Masked Owl Tyto castanops Gould 
cas'-tan-ops— Gk, castanon, chestnut; Gk, ops, face. 
distribution. Tasmania. 
notes. Also called Chestnut-faced Owl. Usually singly or in pairs, 
frequenting forests of large and thinly scattered trees skirting open 
country. It is similar in habits and economy to the Masked Owl. The 
sexes differ considerably in size, the female being larger, more power¬ 
ful, and darker in coloration than the male. 
nest. In a hollow in a tree or in a cliff. 
eggs. Not recorded. 
6 . Grass Owl Tyto longimembris Jerdon 
lon-gi-mem'-bris— L., longus, long; L., membrum, limb. 
distribution. Northern Territory, Queensland, New South Wales, 
and Victoria; also occurs in India, China, the Philippine Islands, 
New Caledonia, and Fiji. 
notes. Usually singly, frequenting grass-lands, chiefly of the coastal 
areas. Very little has been recorded of its habits. It rests during the 
day in “squats" or “hides" under a tussock of grass. Food: rodents, 
large insects, and frogs. 
nest. Under or in a tussock of grass. 
egc-s. Usually four, white, oval in form. Breeding-season: May 
to July. 
