RELATIVE VIABILITY IN MAMMALS AND BIRDS. HIO 



Suvimary of ('olumhip. 



Mr. J. H. Guniey {loc. cit. p. 39) gives on the autliority of 

 Mr. F. E. Blaauw several instances of long-lived Collared Doves 

 {Turtur risorius), ranging from 40 to 30 years, and a, Common 

 Pigeon of 284 years ; a correspondent of my ovt-n, Mr. E. Mellin, 

 has informed me of a Ring-Dove of over 23 years old. The 

 figures of maximum duration on my list are therefore not 

 surprising: they include a Viuaceous Pigeon of just under 19 

 years, a Porto Rico Pigeon of just under 18 years, an Eastern 

 Turtle-Dove and a Green- winged Dove of over 16 years. The 

 maximum dui^ations are on the whole good ; certainly in pi-oportion 

 to size better than in the Anseies. The figures of average dui'atiou 

 are much lower in the Fruit Pigeons, in which they seldom exceed 

 2 years and are frequently under 1 year, than in the Columbidje, 

 where they mostly range from 2 to 5 years. I cannot see any 

 good correlation within the group, between size and viability. 



Pigeons have a long and complex alimentary tract, with, 

 however, the posterior portion and cseca relatively much reduced. 

 They have been kept under various conditions in the period under 

 discussion, but most of the tropical forms have been placed in 

 a heated aviary, sometimes with, sometimes without access to the 

 open air. 



Capt. Flower's highest record is that of a Green-winged Dove, 

 alive after 6 years' dxu-ation. 



PTER0CLETE8. 



Fterocles, whole genus 67 



P. alchata (Pin-tailed Sand-grouse) ... 



/-". arenarins (Black-bellied Sand- 

 grouse). 



P. bicinctus (Double-banded Sand- 9 17 32 



grouse). 



P. exustns (Little Pin-tailed Sand- 11 31 94 



grouse). 



P. fasciatus (Banded Sand-gi'ouse) 



P. iiamagua (Namaqua ,, ,, ) 



Syrrhapies paradoxus (Pallas" Sand- 

 grouse). 



I had no previous information as to the longevity of Sand- 

 grouse. The maximum durations, of which the highest is under 

 8 years, and the average durations, most of which are considerably 

 less than 2 years, show that these birds, in proportion to their size, 

 are less viable than Doves and Pigeons. Their alimentary tract is 

 somewhat similar to that of Pigeons, but the hind-gut and cfeca 

 are relatively capacious. In the period under consideration Sand - 

 grouse were placed in an aviary with heated interior and open-air 

 runs. 



Capt. Flower records Spotted Sand -grouse {P. senegallus) still 

 alive after over 9 years' duration ; a year longer than the highest 

 record I give. 



34* 



