Notes and Obscrvatiuns on a Guan. 299 



to wliiit appears to me to be a very improbable liypotliesis, 

 viz., that their eggs were first white ; then, as the result of 

 a migration to the ground^ coloured ; aud, finally, as a result 

 of a reversion to their original arboreal life, again white. 



(2) The fact that in the case of the Curassows and Guans 

 only two eggs are said, as a general rule, to be laid, also seems 

 to point away from a previous terrestrial existence on the 

 part of the adult birds. Most ground-living game-birds lay 

 clutches of eggs which contain a far greater number, pre- 

 sumably to allow for the greater liability to accidents. 



(3) Capercaillie, Blackgame, and other such-like game- 

 birds in adult life still spend a good deal of their life in 

 trees, feeding on young shoots, although they nest on 

 the ground and their young are protectively coloured and 

 provided for. 



If I understand Mr. Pycraft aright, this would indicate 

 an attempt on the part of these birds to revert to a former 

 entirely arboreal existence. According to my contention, 

 it is rather evidence of an incomplete descent to the ground, 

 a state of things arising in the past from the exigencies of 

 local conditions (e. //., vast tracks of pine, larch, and spruce 

 trees, and consequent cramping). In our Red Grouse and 

 Partridge and in the Quail the process may be considered 

 as complete. It is also suggestive to note that in the game- 

 birds as a group, although the nestlings are generally prone 

 to longitudinal stripiugs, yet when we come to trace these 

 markings from the more primitive to the more modern types 

 the stripes tend to break up into mottliugs. Such a condition 

 of things can be roughly traced, for instance, in a series 

 such as the following — Curassow, Guan, Peacock, Blackcock, 

 Capercaillie, Pheasant, Partridge, Red Grouse, Ptarmigan ; 

 where a progressive descent to the ground seems to go 

 nearly hand in hand with an increased mottling, or vice 

 versa. 



(4) In regard to birds other than those belonging to the 

 Gallinaceous order, Mr. Pycraft {torn. cit. p. 247), referring 

 to the Gannets, Cormorants, Frigate-birds, and Pelicans, 

 says: these " now^ either sporadically, or in the case of 



