MONOGRAPH OF THE PETRELS. 



Signor Fea met with the species on Sao Nicolao, in the Cape Verde Archipelago 

 where it was called " Gon-gon " by the natives. Lieutenant Boyd Alexander failed 

 to observe it during his expedition to these islands, but several specimens were obtained 

 by Padre Ernesto Schmitz in Madeira, where a small colony was found nesting in holes 

 at an elevation of 3,000 feet, the nests being lined with coarse grass and feathers from 

 the birds' own breasts. 



It has been recorded by Mr. J. J. Dalgleish (Ibis, 1890, p. 386 ; id., Pr. Roy. Phys. 

 Soc. Edinb., XL, p. 27, 1899), and Dr. Hartwig (Ornis, VII., pp. 182, 187, 1891) from 

 Porto Santo, Deserta Grande, Ilho do Baixo, and Ilho de Cal. 



The Rev. F. C. R. Jourdain says that the eggs obtained by Padre Schmitz differ 

 considerably in size from those of other species which breed at Madeira, and approach 

 most closely those of Puflinus anglorum, from which, however, they can be at once 

 distinguished by their much lighter weight (Bull. B. O. C, XIX., pp. 37, 38, 1907). 



Adult. General colour above dull slate-grey, the feathers slightly blackish at the 

 ends ; the scapulars decidedly blacker ; upper wing-coverts blackish, more or less washed 

 with grey ; primary-coverts and quills blackish, slightly washed with grey, the 

 primaries ashy on the inner webs, the inner secondaries blackish-brown, with indistinct 

 dusky cross-bars ; upper tail-coverts and tail-feathers light slaty-grey ; the middle 

 of the rump blackish, the sides slaty-grey ; the lateral tail-feathers for the most part 

 white, the two outermost freckled with ashy-grey on the outer web, the third rectrix 

 ashy-grey along the outer web, and slightly vermiculated with grey on the inner web, 

 the fourth rectrix ashy-grey, and having the inner web minutely freckled with white, 

 the central rectrices entirely ashy-grey ; crown of head and sides of head a little 

 darker and more dusky than the back, and only slightly washed with grey ; forehead 

 and lores white, with a few blackish spots on the former ; feathers in front of the eye 

 black, overspreading the ear-coverts ; cheeks white, with a few frecklings of ashy-grey, 

 where they adjoin the ear-coverts ; entire under-surface of body pure white, with 

 no freckled collar across the fore-neck ; sides of chest uniform ashy-brown, 

 accompanied by a few frecklings of the same, these being more distinct on the sides 

 of the body ; under tail-coverts pure white ; under wing-coverts black, the central 

 median and greater coverts slaty-grey, as also the inner webs of the primary-coverts ; 

 the basal axillaries white, the longer ones slaty-grey slightly mottled with white ; quills 

 dusky below, ashy-grey along the inner webs. Total length about 14 inches ; culmen, 

 1.0 ; wing, 10.0 ; tail, 4.15 ; tarsus, 1.25 ; middle toe and claw, 1.6. 



The amount of ashy frecklings on the sides of the body varies considerably, 

 being sometimes very fine and scarcely distinguishable, whereas it occasionally takes 

 the form of coarse dusky-grey frecklings and vermiculations. 



The specimen described is a female from Sao Antonio, Madeira, obtained by Padre 

 Schmitz on June 12th, 1906, and now in the Rothschild Collection. 



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