AN AUSTRALIAN BIRD BOOK. 
41 
Upper silvery-gray; under, rump, tall, forehead white; 
crown, hind-neck black; bill, feet orange-yellow; f., 
Sim. Small fish. 
1 72*Silver Gull (Jameson), Seagull, Sea Pigeon, Larus 
45 novae-hollandiae, A., T., N. Cal., N.Z. (ace). 
Stat. c. shore, inland 17.5 
Head, neck, under, rump, tail white; back, wings delicate- 
gray; wing-tips white and black bars; bill, legs, feet 
blood-red; eye white; f., sim. Scraps, eggs, omni- 
vorous. 
1 73*Paciftc Gull (Larger), Gahianus pacificus. A., T. =vt. 
1 Eur. Greater Black-backed Gull. Stat. c. shore 25 
"This fine gull;" head, neck, under white; tail white 
barred black; back, wings slaty-black; eye white; legs 
yellow; deepened bill orange tipped red; f., smaller; 
young up to 4 years mottled-brown, becoming more like 
adult each year. Fish, crabs, carrion. 
F. 33. STERCORARIIDAE (4), SKUAS, Robber Gulls, Sea 
Pirates, 7 sp.— 4(0)A., 1(0)0., 4(0)P., 3(0)E., 
4(0)Nc., 4(1)N1. 
1 74 Great Southern Skua, Robber Gull, Port-Egmont-Hen, 
4 Sea-Hawk, Hakoakoa, Megalestris antarctica, S. 
Oceans, A., N.Z. =vt. Eur. Great Skua. 
Mig. r. shores 23 
Upper blackish-brown; under chocolate-brown; wing white 
patch; centre tail feathers project ^in.; f., sim. Stolen 
fish, carrion. 
2 75 Kichardson Skua (Arctic), Arctic (Parasite) Gull, 
3 Long-tailed Jaeger, Sea-Pirate, Boatswain-Bird, Teaser, 
Stercorarius crepidatus, cos. Mig. r. shores 20 
Dimorphic (two phases) — 1. Dusky upper; blackish cap; 
narrow whitish collar; under white; brown band on 
chest; brown band on wing; centre tail feathers pro- 
ject 3ins.; strong bill, claws. 2. Under mottled and 
barred brown and whitish; follow bay steamers; f., 
Sim. Stolen fish. 
The Robber Gull, or Skua, of Victoria is, strange to say, identical 
with the Skua of England. The one that followed the s.s. Lady 
Loch to the Summer School is better known in England as the 
Arctic Gull or Richardson Skua. It breeds in the far North, so 
it is a great traveller. 
One interesting fact about these birds is that they show two sets 
of plumage. Thus, while each bird, as it gets older, usually 
changes its immature and almost uniform dusky plumage for a 
white under-surface, an incomplete white collar, and a blackish 
cap, yet some retain the dusky plumage throughout life. This 
is a good example of "dimorphism." as it is termed. Usually, 
instead of picking up their own prey, they watch until some other 
bird has captured a meal, and then they rapidly pursue it and 
cause it to disgorge. They do not skim over the waves like 
