6 BRITISH BIRDS, WITH THEIR NESTS AND EGGS. 



The changes from youth to maturity take a longer time for their accomplish- 

 ment among the Gulls than among the Terns. As among the latter the nesting 

 plumage is succeeded in a very short time by the garb of the J 7 ear, which is 

 changed by moult in each spring and autumn, till the final and perfect plumage 

 of the species is donned, in, among the larger members of the family, their fourth 

 or fifth year, although some of the smaller Tern-like species may be in fully 

 mature dress after the second spring moult. 



" Even in those species," as Mr. Saunders points out, " which are destitute 

 of hood at all seasons, there is a seemingly endless variation in the pattern of the 

 primaries, the general tendency being to an increase in the lighter and a diminution 

 in the darker portions of the webs with the advancing age of the individual a 

 rule which also holds good with many of those species the adults of which bear 

 a hood in the breeding season, whilst on the other hand, there are others which 

 exhibit the apparent anomaly of having a hood in the immature stage and losing 

 it in the adult plumage." 



The Stercorariida, the SKUAS, DuNGHUNTERS, or BO'SUNS (as they are more 

 popularly known), differ from the Laridce in their general appearance, habits, and 

 structure. The robber instincts, with which they are so strongly endowed, have 

 made them special objects of observation. Their aerial bullying pursuit of the 

 Terns and weaker sea-birds (who with terror stricken screams attempt to escape by 

 vigorous flight, but are rarely successful without having to disgorge which is the 

 object of the Skuas' attentions the results of the recent fishing forays from which 

 they are returning), never ceases to be a spectacle followed with the most absorbing 

 interest by everyone who has the opportunity of watching these relentless pirates 

 in their native haunts. The term " Dunghunters," from which they have obtained 

 their general generic appellation Stercorarius, has been applied to them from the 

 erroneous notion that that is the object of their pursuit of Terns and other sea- 

 fowl, instead of its being the fish with which the birds are gorged. 



There are seven recognized species of Skua included under the two following 

 genera : 



i. Afi'galestris, or GREAT SKUAS, containing four species, of which one, breeding 

 in Britain, inhabits the subarctic regions of the northern hemisphere in summer, 

 and its temperate latitudes in winter ; and three have an antarctic habitat, ranging 

 northwards to the extremities of the great southern continents in winter. 



2. Stercorarius, or LESSER SKUAS, embracing three species (one of which 

 visits and one breeds in the British Isles), whose home is the arctic or subarctic 

 regions, whence in winter they wander southward on all the continents, across the 

 equator far into the southern hemisphere. 



