JACKDAW. ii 



to the relative abundance or scarcity of nesting-sites. 

 Some of these colonies are very extensive, as, for instance, 

 on the cliffs above Devil's Hole in the Peak, and in the 

 hollow trees in Sherwood Forest. Like the Rook, the 

 Jackdaw may be seen almost daily at its nesting-colony 

 all through the year. The nest of this species varies 

 considerably in size. If the selected hole or crevice is 

 large, it is generally rilled with materials, and in some 

 cases a vast mass is accumulated, being added to each 

 season ; if the site is small but little nest is made, and 

 in many cases no provision whatever is made for the 

 eggs. I have taken the eggs from holes in the trunks 

 of oak trees in Sherwood Forest where the decayed wood 

 alone served for a nest ; but on the other hand some of 

 the nests at this colony are several yards in height, the 

 entire hollow trunk or limb having been closely packed 

 with sticks and other rubbish, at the top of which the 

 nest itself has been made. The foundation of the nest 

 is made of sticks and twigs, pieces of turf, and occasionally 

 all kinds of curious litter and rubbish, the cavity con- 

 taining the eggs being formed of dry grass, pieces of moss, 

 leaves, and straws, and lined with fur, wool, and feathers. 

 Numbers of nests are often made close together, some- 

 times several in the same hole or cleft. I have known as 

 many as twelve in a single hollow tree. Many nests are 

 quite inaccessible. 



RANGE OF EGG COLOURATION AND MEASUREMENT : 

 The eggs of the Jackdaw are from four to six in num- 

 ber, five being the usual clutch. They vary from the 

 palest of blue (almost white) to bluish-green in ground 

 colour, spotted and blotched with very dark brown, 

 nearly black in intensity, olive-brown and grayish-brown, 

 and with underlying markings of pinkish-gray. Some 

 specimens are much more heavily marked than others, 

 and many have the spots small, deep-coloured, and more 



