KELATIVE VIABILITY IX MAMMALS AND BIRDS. 511 



conditions of captivity have pressed most heavily on the Herons. 

 I have not sufficient information to point to any special unfavour- 

 able circumstance in the case of the Herons. 



Oapt. Flower records no example of the Herodiones still alive 

 after 12 years. 



ODONTOGLOSSvE. 



T->„ No. of Av. dur. Max. dm: 



PH(ENIC0PTERID.E. j,,^^i^,_ in months, in mouths. 



Phoenicopterus, whole genus 23 82 273 



P. ignipalliatus (South American 5 42 105 



Flamingo). 



P. rose?6s (European Flamingo) 9 163 273 



P. r^Sm (Ruddy „ ) 9 21 147 



I can find no published statements regarding the longevity of 

 these large birds," and the maximum duration of nearly 23 years 

 for a European Flamingo is therefore specially interesting. I 

 know of no reason for the greater success of the European form. 

 The distribu^tion of individual durations with regard to the 

 maximum durations shows that the deaths with low duration 

 have nearly always taken place soon after arrival : if the birds 

 of any of the three species survived two or three months, they lived 

 yeai"S. These birds live on a mixed diet, in captivity taking a 

 good deal of grain ; the alimentary tract is relatively long and 

 slender, but the posterior portion and the c^eca are more capacious 

 than in most birds. They have been kept with complete exposure 

 to the open air in summer, whilst in winter, in the period to 

 which the records refer, they were usually transferred to an aviary 

 with open-air cages and heated retreats. Flamingoes have a 

 high longevity and viability under such conditions. 



PALAMEDE^. ^l^ itln^s. ^moS. 



Cha^lna ci'isiata {Grented ^cresbuier) . . . 11 45'8 115 



C.derUana (Derbian „ )... 8 16-5 84 



Palamedea cornuta {S.ovn.eA. ,, ) ... 3 31'1 43 



I am unaware of published records as to the longevity of 

 Screamers. The maximum duration, over 9 years in the case of 

 a Crested Screamer, is surpassed by two examples of the species, 

 at present alive in the Gardens, after a duration of nearly 13 years 

 As in the case of the Flamingoes, the incidence of the mortality 

 was especially heavy on new arrivals : if the birds lived a few 

 months, they usually approached the maximum duration i-ecorded. 

 Screamers are large, bulky birds, with the alimentary tract of a 

 primitive type, the hind-gut and cfeca being relatively capacious. 

 They have been kept under conditions relatively similar to those 

 of the Flamingoes, and certainly in proportion to their size 

 cainiot be regarded as highl)^ viable. 



