AN AUSTRALIAN BIRD BOOK. 41 



Upper silvery-gray; under, rump, tail, 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-noUandiae, 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. 

 P. 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 Southera 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. 



'A 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 



