Family SYLVIIDAE. 



Sylvia sylvia (L.) ') - Whitethroat. 



(Plates 49-51, fig. a-1). 

 (Snouckaert: Avifauna Neerlandica, p. 39, No. 89). 



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 



greenish-white, -grey or-yellow ; bluish white, 

 reddish yellow. 



the colouring consists mostly of a cloudy 

 marking in darker variegations of the ground 

 colour; spots and speckles lying more or 

 less deep are of a leaden grey appearance 

 (in various shades); at the surface there 

 are sometimes large reddish brown (oo- 

 rhodein) spots. Characteristic of this species 

 are leaden grey spots at the base where 

 they mostly form a very distinct ring or 

 closed cap. 



18.8 X 13.9 millimetres. 



0.114 gram. 



not specially characterized. 



usually slightly shorter and more bellied 

 than those of the other species of this 

 family. 



consists of vegetable materials, especially 

 seed down and material spun by insects; 

 lined with hair. 2 ) 



as a rule near the ground, in various shrubs; 

 also in tall grass, and on arable land where 

 there are many weeds; always under the 

 shelter of luxuriant vegetation. 



5—6 (after-set: 4—5). 



May— July. 



about 13 days. 



*) See also for this species the general remarks respecting the Family. 



2 ) Mr. G. Wolda (Wageningen, prov. Gelderland) informed me that a few 

 years ago he found at Oranje-Nassau's Oord a sylvia-nest which was pierced 

 on the outside with about 120 leaves of pear blossom. 



