PETRELS. 43 



Order IX. PROCELLAR1IFORMES. PETREL-TRIBE. 



The Albatroses and Petrels bear a strong superficial resemblance to J-P^? s -i 

 the Gulls, to which, however, they are not even remotely related. They 

 may be distinguished by the curious shape of the nostrils, which have 

 tubular openings, while in the Gulls these are slit-like. The various 

 members of this Order vary greatly in size, the Albatroses, which are 

 the largest of the Petrels, possessing a wider spread of the wing than 

 any other known bird, while the Storm-Petrels are hardly larger than 

 a Swallow. All are endowed with great powers of flight and have a 

 peculiar musky odour, specially noticeable in the Giant and Fulmar 

 Petrels. The Albatroses build a fairly substantial nest and breed in 

 vast colonies in the open, but the great majority of Petrels deposit their 

 single egg in holes and crevices of the rocks or in burrows, using little 

 or no lining. The egg is dull white, often marked, especially in the 

 smaller species, with a ring of reddish spots round the larger end. The 

 young when hatched are covered with thick white or grey down, and 

 are for a long time helpless and dependent on the care of their parents. 



Family I. DIOMEDEIDVE. ALBATROSES. 



The Albatroses, of which three genera and about fifteen species are [Case 23.] 

 recognised, are the most powerful of all birds on the wing. One of the 

 largest and best known species is the Wandering Albatros (Diomedea 

 exulans] (355), which measures nearly eleven feet across the expanded 

 wings. This bird breeds in great colonies on the high table-lands of 

 some of the islands in the Southern Ocean, repairing there in October 

 and building a mound of mud and grass with a slight hollow in the top. 

 The single egg is not hatched till January, and the young is for a long 

 time helpless and covered with thick white down, as may be seen in the 

 young Royal Albatros (D. regid) (357). The immense expanse of the 

 wings in flight is seen in the rare White-winged Albatros (T>. chionopterd) 

 (358) exhibited at the top of the Case. It is interesting to note that a 

 specimen of the Black-browed Albatros (D. melanophnjs) (356) was 

 captured in Cambridgeshire in 1897. Other species of the family are 

 the Yellow-nosed Albatros (Thalassogeron chlororhynchus) (359), and the 

 Sooty Albatros (Phcebetria fuliginosd) (360). 



Family II. PROCELLARIID.E. PETRELS. 



The most aberrant of the Petrels are undoubtedly the three species [Case 23.] 

 included in the subfamily Pelecanoidirue or Diving Petrels, which are 

 represented by Garuot's Petrel (Pelecanoides garnoti) (361). Like the 

 Little Auk (404) (Case 24), which they closely resemble in general 

 appearance, they have a hurried flight and dive into the sea in pursuit 

 of their prey without any interruption in the action of their wings, and 

 emerge from beneath the surface flying. Unlike the other Petrels, they 

 are generally found singly or in pairs and nest sporadically. 



