FALCONIDAE. 



year until they had gradually passed from almost plain white to 

 eggs with dark brown markings *). 



On comparing the stage of development of the embryos of one 

 nest, it appeared to Altum ^) that the most strongly marked eggs 

 were laid first. 



FALCO SUBBUTEO L. 



In general these eggs are, as compared with tinnunculus-eggs, 

 distinguished by a smaller intensity of the brown colour, which is 

 more yellowish; further, by a fine, close marking which almost al- 

 ways completely covers the ground; and finally, by a slightly more 

 elongated shape. The determination is very much facilitated when 

 one has the whole set before one. 



As Kleinschmidt •') says, it is mostly the incubated, weakly 

 coloured eggs, and eggs of after-sets of tinnunculus, which are often 

 taken to be subbuteo-eggs. 



Observations made by Qanske *) in a certain area during many 

 years indicate that the smaller pale pink or bright red eggs are 

 laid by young female birds, and are most probably their very first set. 



CERCHNEIS TINNUNCULUS (L.). 



The markings consist mostly of large, usually rather sharply 

 outlined spots and smears; frequently, however, they only consist 

 of many small specks. 



The pitch-black spots on some eggs I consider to be identical 



') See also: „EinzeIeier vom Mausebussard", von Dr. R. Thielemann (Zeitschr. 

 f. Ool. u. Ornith., XV. Jahrg., p. 86), who is inclined to consider clutches 

 consisting of one egg as indications of the end of the production period. 



-) Die Eier von Bufeo vulgaris. 'Journal f. Ornith. 1863; id. 1864). 



3) Zeitschr. f. Oologie, 111, p. 14 and 15. 



*) Zeitschr. f Oologie, 111, p. 33. 



