142 THE FALCONS 



taken possession of. There is no nest, the eggs being laid on the bare ground, 

 rock, or wood, and in the case of some other bird's nest the top is flattened out. 

 The eggs vary as a rule from four to six in number, rarely seven, but eight have 

 been met with two or three times, and nine eggs were found in one nest in Norfolk 

 on the ground in the Runton district. They are laid at intervals of forty-eight 

 hours, and vary a good deal in appearance, some showing much of the yellowish 

 white ground, and others being completely suffused with colour, which varies from 

 very deep rich red-brown, almost black, to light tawny or reddish yellow. Some 

 clutches only show the light tawny markings, others have various shades of red- 

 brown, while some have only the deep blackish red markings on the white ground. 

 A rare and beautiful type shows conspicuous purplish or lilac shell-markings. There 

 is also considerable variation among eggs even in the same clutch. Average size 

 of 160 eggs, 1'52 x 1*20 in. [38*8 x 30'6 mm.]. Incubation is chiefly performed by 

 the female, but the male goes on for a short time when the female leaves the nest 

 (J. L. Bonhote). Careful observations on the duration of the breeding period by 

 J. G. Tuck and others show that it lasts 27-28 days from the laying of the last 

 egg, and the statements that it lasts only for 19 days (Bau) and 21 days (Dettmers) 

 are certainly erroneous. The eggs may occasionally be found early in April in 

 England, but more commonly about the third week in that month or early in May. 

 Only one brood is reared in the season, but if the first clutch is taken a second 

 is subsequently laid. [F. c. B. j.] 



5. Food. Chiefly fieldmice, but also small birds, moles, lizards, frogs, 

 cockchafers, grasshoppers, beetles, butterflies, caterpillars and other insects, and 

 occasionally also earthworms and carrion (?). The young are fed on mice, and by 

 both parents, [w. p. p.] 



The following species and subspecies are described in the supplementary chapter 

 on " Rare Birds " : 



Iceland-falcon, Fdlco rusticolus isldndus Brunnich. 



Gyr-falcon, Fdlco rusticolus rusticolus Linnaeus [Fdlco gyrfdlco Linnaeus]. 

 American peregrine-falcon, Fdlco peregrinus andtum Bonaparte. 

 Redfooted-falcon, Fdlco vespertinus Linnaeus. 



Lesser-kestrel, Fdlco naumdnni Fleisch [Fdlco cenchris Naumann]. 

 [F. c. B. j.] 



