The Pedrero or Stone-Quarrier 291 
proper was built of bents and fibres and lined with wool and a few 
feathers. [It contained four pale blue eggs marked with a rufous 
ring at the larger end, in size they were between those of our 
Wheatear and the Blue Rock Thrush. They were alas! on the 
CAVERN NEAR A SUMMIT OF THE LOWER SIERRA SHOWING CAVITIES FORMED BY 
SAND-BLAST IN ROCK. NESTING-PLACE OF THE BLACK WHEATEAR. 
(Zhe nest is tn a cavity tmmediately above the field-glasses.) 
point of hatching; so I lost the only chance I have ever had of 
getting a perfect set of eggs of this curious bird. 
Although I have found many nests since, the majority have been 
empty and a few contained young birds; such are the ups and 
