THE CAN NETS 2047 



Hebrides, and although less numerous on the Norwegian coasts, reappear in vast 

 swarms on the shores of North America. The gannets on the Bass Rock have been 

 so frequently described, that it will be unnecessary to give any account of the won- 

 drous scene here. It may be mentioned, however, that the birds usually assemble 

 in March, although laying does not generally commence till May; and some idea of 

 the vast numbers of these birds may be obtained from the fact that formerly from 

 fifteen hundred to two thousand young have been taken in a season. The nest, 

 which is generally some six inches in height, is formed of a mass of seaweed and 

 grass placed upon the bare rock, and in this is laid a single egg, which is at first 

 chalky white, with a faint blue tinge. During incubation, the birds become so tame 

 that they will allow themselves to be handled, and it is somewhat curious, that on 

 the ledges of the Bass Rock almost all the sitting birds have their heads turned 

 toward the cliff. Gannets feed exclusively upon fish, and commit great devastation 

 upon the shoals of herrings and pilchards, in search of which they often wander for 

 long distances. Couch observes that ' ' the gannet takes its prey in a different man- 

 ner from any other of our aquatic birds; for, traversing the air in all directions, as 

 soon as it discovers the fish, it rises to such a height as experience shows best cal- 

 culated to carry it by a downward motion to the required depth, and then, partially 

 closing its wings, it falls perpendicularly on the prey, and rarely without success, the 

 time between the plunge and immersion being about fifteen seconds. ' ' The serrated 

 third claw of the gannet, like that of the cormorant, appears to be for the purpose 

 of dressing the plumage, and not for aiding in the capture of the prey, which is 

 taken entirely by means of the beak. 



On many of the islands of the southern seas gannets, or boobies, of various 

 species, breed in vast numbers and exhibit remarkable tameness, or rather absence 

 of fear. Among such breeding places may be mentioned St. Paul's Rocks, Booby 

 island off Fernando de Noronha, and Raine island off Northeastern Australia. The 

 white-bellied gannet (S. leucogaster) of St. Paul's Rocks and Raine island, makes a 

 slight nest of green twigs and grass on the ground; while the blue- eyed ganuet 

 (S. cyanops) merely digs a hole about an inch and one-half deep. The latter species 

 is nearly white, with the naked parts of the face blue and the iris bright yellow; 

 while the smaller Australian S. piscatrix differs from both the others by its bright 

 red feet. Moseley writes that ' ' on the low cliffs of Booby island the noddies [terns] 

 and boobies nest on all the available ledges, and sat on their nests quite undisturbed 

 as we rowed past them. It was curious to see the doves nesting together with 

 these two sea birds on the same ledges and with their nests intermingled. ' ' Re- 

 mains of extinct gannets are found in the lower portion of the Miocene deposits of 

 France; while the rocks belonging to the middle portion of the same period have 

 yielded bones of a gannet-like bird with wings even longer than those of the alba- 

 tross, for which the name of Pelargornis has been proposed. Nearly allied to the 

 latter is the so-called Argillornis from the much older London Clay of England. 

 Still more remarkable is the tooth-billed cormorant {Odontopteryx} , of the latter 

 formation, which, while apparently allied to the cormorants, differs from all existing 

 birds in having the bony margins of the jaws produced into a number of tooth-like 

 processes. 



