126 THE NESTS AND EGGS OF 



occasionally to make use of the deserted nest of a 

 Raven in these localities. The bird probably pairs for 

 life, and either uses the same nesting site yearly, or has 

 a selection of several in various parts of its rocky haunt 

 which are used alternately. Of its actions at the nest 

 nothing of exceptional interest has been recorded. 



Range of egg colouration and measurement : 

 The eggs of the Iceland Jer-Falcon are three or four in 

 number, but in some cases apparently only two. They 

 are exceedingly handsome, and subject to much the 

 same range of variation as those of the Greenland Jer- 

 Falcon. Eggs in the same clutch not unfrequently vary 

 considerably amongst themselves, as is often the case 

 in this group of birds. They are buffish-white or very 

 pale buffish-brown in ground colour, spotted, blotched, 

 mottled, and washed with reddish-brown, brick-red, and 

 paler brown, and with a few and indistinct underlying 

 markings of gray. ' The usual type is so thickly, if 

 somewhat unevenly, washed with reddish-brown as to 

 conceal all trace of the ground colour, but other types 

 occur in which the markings — either brick-red or 

 reddish-brown — are scattered and defined, and show 

 much of the pale ground between them. Average 

 measurement. 2*4 inches in length by tq inch in breadth. 

 Incubation is probably performicd chiefly by the female, 

 but the duration of the period is unknown. 



Diagnostic characters : The eggs of the Iceland 

 Jer-Falcon present no constant character by which they 

 can be distinguished from those of the other Jer- 

 Falcons. The locality, in this case, is sufficient to 

 identify them. Their larger size, coarser grain, and 

 generally more ovate form prevent them from being 

 confused with those of the Peregrine. 



