of certain Birds in North-eastern Africa. 123 



ties. In other cases the bird itself builds a nest of branches, 

 without much art, rather small and about li inch deep. But 

 few of the eggs are elongate in shape j some are strongly 

 rounded, and most of them have a stout oval form. The longest 

 out of sixteen specimens is 23 ^ lines long, 17^ lines broad ; the 

 shortest and narrowest 21 lines long and 16| lines broad. 



The eggs of this bird, compared with those of Falco peregrinus 

 from Northern and Central Germany, North-eastern Russia, 

 and the northern parts of America {Falco anatum, Bonap.), are 

 generally lighter in colour, less red, and with more delicate 

 markings. One specimen only, of a small size, is marbled with 

 dark brownish-red ; most of them are distinguished by a light 

 ground-colour (sometimes dirty-white, sometimes brownish- 

 yellow), and by fine, rounded, darker or lighter yeilowish-hrown 

 spots, dots, and points. By the size alone, they cannot always 

 be distinguished from those of the Peregrine, though they never 

 attain to such a size as sometimes occurs in the eggs of that 

 species. But there is a difference in the structure; for whilst 

 the pores in the eggs of the Peregrine are less oblong and 

 rather infundibuliform, those in the eggs of the present bird are 

 more distinctly marked and serrated. The weight of the empty 

 shell is between 58 and 73 grains. 



The young birds are fledged in the beginning of May, and 

 resemble those of Falco lanarius. Their tarsi have a remark- 

 able dark bluish-green colour. 



Three other eggs, strongly convex and taken from one nest *, 

 differ from the former by their beautiful coloration and con- 

 siderable size. They are 23f lines long, 18 or 19 lines broad, 

 the ground-colour gradually changing from violet-red to flesh- 

 colour and then to pale reddish-brown, with obsolete fine dots. 

 At first I was inclined to consider these as a southern variety of 

 the eggs of F. lanarius ; but Heuglin assures me that this spe- 

 cies does not breed in that locality, and that he has met with it 

 in North-eastern Africa from October to March only. If this 

 observation be correct, the eggs must belong to F. tanypterus, as 

 it is impossible to refer them to F. peregrinus. 



* There were four eggs in this nest. 



K 2 



