CHIFFCHAFF. 101 



disturbed glides very quietly from her eggs. In visiting 

 the nest the old birds are exceedingly cautious, if any 

 danger threatens, and hop restlessly about for a long 

 time before they will betray their secret. This species is 

 not at all social during the nesting season. 



RANGE OF EGG COLOURATION AND MEASUREMENT : 

 The eggs of the ChiffchafF are from five to seven 'in 

 number. They range from white to white tinged with 

 yellow in ground colour, somewhat sparingly spotted and 

 freckled with dark or pale reddish-brown, and with a 

 few underlying markings of violet-gray. Most of the 

 spots are, as a rule, on the larger end of the egg, 

 but occasionally they are more uniformly distributed. 

 Average measurement, *6 inch in length by '46 inch in 

 breadth. Incubation, performed chiefly by the female, 

 lasts thirteen or fourteen days. 



DIAGNOSTIC CHARACTERS : The eggs of the Chiffchaff 

 are best distinguished by their few and dark reddish- 

 brown coloured markings. The eggs of some of the 

 Titmice closely resemble them, but the formation and 

 locality of the nest prevent confusion. 



Family TURDIDyE. Genus PHYLLOSCOPUS. 



Sub-family SYLVIIN&. 



WILLOW WREN. 



PHYLLOSCOPUS TROCHILUS (Linnceus). 

 Single Brooded. Laying season, April, May, and June. 



BRITISH BREEDING AREA : The Willow Wren is 

 commonly distributed throughout the British Islands, 

 extending to almost every portion where trees occur, 



