Family LARIDAE. 



Larus canus L. - Common Gull. 



(Plate 164, fig. a— d). 

 (Snouckaert: Avifauna Neerlandica, p. Ill, N°. 265). 



Colour of surface of shell: 



Colour of spots : 



Average dimensions: 

 Average weight of shell : 

 Texture of shell: 

 Shape : 



Nest: 



Site of nest: 

 Number of eggs: 

 Breeding season: 

 Duration of incubation : 



olive brown, olive green, olive yellow, or 

 olive grey, i]i various shades ; almost always 

 of an oily gloss. 



blackish brown, mostly of a round shape; 

 underlying spots show through grey; the 

 markings are as a rule spread fairly evenly 

 over the whole egg and rather frequently 

 form a zone at the big end. 



58 X 41 millimetres. 



3.3 grams. 



as in argentatus. 



mostly ovoidal. 



mostly constructed rather strongly of vege- 

 table material. 



on the ground. (Breeds in colonies). 



2-3. 



May, June. 



about 4 weeks. 



