Family STERNIDAE. 



Sterna cantiaca Gmelin Sandwich Tern. 



(Plates 170-173, fig. a-p). 

 (Snouckaert: Avifauna Necrlanclica, p. 114, No. 272). 



Colour of surface of shell: 



Colour of spots: 



Average dimensions: 

 Average weight of shell : 

 Texture of shell: 



Shape : 



Nest and its site: 



Number of eggs: 

 Breeding season: 

 Duration of incubation: 

 ♦ Remark: 



ranges from white, through cream colour and 

 light yellow, to brownish yellow, in va- 

 rious tints; aberrations occur in different 

 shades of colour. 



from dark brown to black; underlying spots 

 show through purplish or grey. (For the 

 nature of the markings see the introduction 

 to the XLI. and XLll. Families). 



51 



36 millimetres. 



2.2 grams. 



considerably finer and more even of grain 

 than that of L. ridihimdus. 



varies from pointed oval to pyriform. 



on the ground (in long grass amongst mate- 

 rial that has been washed ashore or in 

 the sand) in a little hollow which is some- 

 limes lined with a little dry vegetable 

 material. (Breeds in colonies). 



generally 2. * 



second half of May, June. 



about 3 weeks. 



Norman Gii.roy states that in a little, very 

 distant, breeding place (in one of the 

 British Isles) — where however there is an 

 ahundance of food — 99 per cent of the 

 clutches usually consist of three eggs. 

 (British Birds, vol. Ill, p. 130). 



