VOL. vii.] THE DARTFORD WARBLER. 217 



Used once only. — Duck's down, a ; rabbit's fur, b ; 

 dodder {Cuscuta epithymuin), c ; willow-down (Salix 

 repeyis), b, c ; bracken (Pteris aquilina), b. 



The dwarf-furze (not the common species) and ground- 

 lichen are distinctive features in these nests, and I 

 know of no other Passerine bird that makes use of 

 them. Feathers are much more used than is generally 

 supposed,* and with the egg-cases of one species of 

 spider appear to serve the purpose of binding other 

 materials together. 



The white and conspicuous egg-cases of another species 

 of spider are, however, apparently used for decorative 

 purposes, and are placed on the outside. These are 

 sometimes adhering to pieces of ling, but I have also 

 seen them brought separately to the nest. Some nests, 

 and usually those in ling, are made entirely of ling and 

 lined with feathers, hair, and rootlets. Wool is quite 

 absent from all the nests examined. 



Measurements of nests : Diameter across the top, 

 3-4 in., ditto, inside, 2 in. ; depth outside 2J-2| in., ditto, 

 inside, 1 J-2 in. ; thickness of wall at top, 1-J in. 



The faeces of the young and adults are curious and 

 distinctly rose-pink in colour. These are removed 

 immediately from the nest, which is always beautifully 

 clean, and it is difficult to distinguish between a nest 

 from which young have flown and a new one. The 

 young bird when first hatched is very dark and black - 

 skinned, the inside of the mouth is orange-red, paler 

 towards the edges, and there are two black tongue - 

 spots. 



The eggs cannot easily be confused with those of 

 any other British breeding bird. Although they very 

 shghtly resemble one of the commoner types of the 

 Common White throat, there is something very distinctive 

 about them to the practised eye, and they are on the 

 average smaller and do not show so much gloss. I have 



* I find them in ten out of sixteen nests and in one nest pulled to 

 pieces for examination there were no less than forty-seven feathers. 



