NON-L\DIGENOUS BRITISH BIRDS. 239 



with blackish-brown of various shades, and with under- 

 lying markings of gray. Much variation occurs in the 

 character of the marking. Some eggs are covered with 

 moderately large and irregular blotches, some of the latter 

 joined together with irregular streaky marks ; others 

 have the markings small and streaky ; others have them 

 large and pale. As a rule most of the spotting is on the 

 major half of the e.gg, and the gray underlying markings 

 are seldom conspicuous or numerous. Average measure- 

 ment, 17 inch in length, by 1*2 inch in breadth. The 

 duration of the period of incubation is unknown, neither 

 has the sex which performs the task been determined. 



Diagnostic characters : Many of the eggs of the 

 Common Stilt closely resemble those of the Avocet in 

 colour, but are much smaller in size. I cannot find any 

 reliable character by which the eggs of this Stilt can be 

 distinguished from those of certain allied species, but the 

 locality is sufficient to identify them. 



Family CHARADRIID^. Genus Recurvirostra. 



Sub-family TOTANINAi. 



COMMON AVOCET. 



Recurvirostra avocetta, Li7inaius. 



(British : Formerly bred ; rare spring and autumn coasting 

 migrant.) 



Single Brooded. Laying season, INIay, and early June. 



Breeding area : Southern Pal^earctic and Ethiopian 

 regions. The Common Avocet breeds on some of the 

 islands off the Dutch and Danish coasts, on the marshes 

 in the delta of the Rhone, in the marismas of Southern 

 Spain, in the valley of the Danube, and on the lagoons 



