ON DEATHS IN THE GARDENS IN 1920. 179 



8. Report on Deaths which occurred in the Zoological 

 Gardens during 1920. By N. S. Lucas, M.B., F.Z.S., 

 Pathologist to the Society. 



[Received January 31, 1921 : Read February 22, 1921.] 



On Jan. 1st, 1920, there were living in the Gardens : — 



586 mammals, 1333 birds, 411 reptiles. 



(826) (2162) (486) 



To these were added during the year : — 



450 mammals, 1138 birds, 693 reptiles. 



(446) (1356) (683) 



Giving a total of :-^ 



1036 mammals, 2471 birds, 1104 reptiles. 

 (1272) (3518) (1169) 



The total of deaths which took place during the year 1920 

 was 1101. This was made up as follows : — 



333 mammals, 490 birds, 262 reptiles. 



(356) (857) (467) 



This gives a percentage of deaths to animals living in the 

 Gardens during the year of : — 



32-1 19-8 20-1. 



(27-9) (24-3) (39-4) 



If only those animals which had lived in the Gardens for six 

 months or more are considered (it being assumed that these are 

 acclimatized), the number of deaths is as follows : — 

 167 mammals, 230 birds, 50 reptiles. 



Giving a percentage of deaths of : — 



161 9-3 4-5. 



(16-9) (16-4) (138) 



As this is the first year in which the numbers have come up to 

 pre-war standards, or nearly so, the figures for 1913 are given in 

 brackets corresponding to each of the above. 



Comparing these figures, those for mammals remain very 

 constant. The increase in 4-2 per cent, of the death-rate may 

 be considered as due to the higher ratio of unacclimatized 

 mammals. If only the acclimatized are taken, there is a drop of 

 0'8 per cent. 



The total number of birds in the Gardens shows a drop of 

 approximately 1100. The bird population in 1913 was nearly 

 50 per cent, greater than now. The total and acclimatized death- 

 rate has diminished. In the latter case this is very marked. A 

 reference to the diminished figures for avian tuberculosis and 



