114. THALASSOGERON CAUTUS (Gould). 



(SHY MOLLYMAUK.) 

 (Plate 99.) 



Diomedea cauta, Gould, P. Z. S., 1840, p. 177 ; id., Birds Austr., VII., PL 40 (1844) ; 

 id., Handb. Birds Austr., II., p. 434 (1865) ; Coues, Pr. Acad. Philad., 1866, 

 pp. 183, 188 ; Le Souef, Ibis, 1895, p. 413 ; Ogilvie-Grant, Ibis, 1905, p. 558. 



Thalassarche cauta, Giglioli, Faun. Vertebr. Oceano, p. 58 (1870). 



Thalassogeron cautus, Ridgway, Man. N. Amer. Birds, p. 53 (1887) ; Salvin, Cat. Birds 

 Brit. Mus., XXV., p. 449 (1896). 



Capite et collo cinereis ; dorso obscuriore ; alis nigrescentibus ; cauda grisea ; 

 uropygio et corpore toto subtus albis. 



Although this bird resembles its ally T. layardi in the light horn-coloured bill with 

 pale yellow tip, while the culminicorn is also horn-coloured like the latericorn, and not 

 bright yellow as in many of the allied species, it can be distinguished from all other 

 members of the genus by its larger size, the grey colour on the sides of the mandibles, 

 and the yellow line at the base of the lower mandible. 



T. cautus is undoubtedly an inhabitant of the Australian Seas, and according 

 to Professor Giglioli it was seen, during the voyage of the "Magenta," on April 

 24th, 1867, in Lat. 39° 36' S., Long. 126° 25' E., when it followed the ship to the 

 entrance of Port Phillip. The species was also abundant in Bass' Straits and along 

 the coast to Port Jackson, and on leaving Sydney it continued in the track of the 

 vessel till it reached Lat. 32° 27' S., Long. 173° 53' E., on the 2nd June. 



Gould observed T. cautus off the coast of Tasmania, also in Recherche Bay at 

 the south entrance to d'Entrecasteaux Channel, where it was doubtless attracted by 

 the large quantities of fat and other remains of whales which were floating on the 

 water ; the stomachs of those examined contained fragments of large fish, barnacles 

 and crustaceans. 



He believed that the birds nested in small companies on the rocky ledges of 

 the cliffs, and on the top of Albatros Island, one of the Hunter group, off the north- 

 west point of Tasmania. Both sexes take part in the process of incubation, and 



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