346 yir. Swynneiton on Mixed Bird-parties. 



like stamps, which are to be arranged methodically in an 

 album. We have not finished with them when we have 

 cleverly elaborated a system which ensures that we shall 

 Itnow exactly where to find them in the cabinets of a museum. 

 On the con trai'v, they are natural groups of organic creations 

 with independent organic histories and origins, with inde- 

 pendent or particular areas of distribution, and doubtless 

 with independent ecological life-stories. Are such things 

 expressed or implied when we find in a recent and colossal 

 work that no more can be done with a huge family like the 

 Icteridse than to write it down as one long continuous and 

 tremendous list of genera, without analysis, without sub- 

 divisions or divisions, without a hint as to phylogenetic 

 relationships or diversities, Avithout an indication that, for 

 all one can tell, judging solely by this method of classifica- 

 tion, the first genus may not be closely allied in all respects 

 with the last? 



XVI. — Mixed Bird-parties. 

 By C. F. M. SwYNNERTON, C.M.B.O.U. 



The occurrence of mixed bird-parties in the British Isles 

 tends, I think, to escape notice to some extent through 

 the fact that the intervening spaces are well filled up by 

 scattered birds that are searching for their food inde- 

 pendently. 



In south-east Africa, through the relative scarcity of 

 intervening birds, they are far more conspicuous, and they 

 would appear to be equally so in portions of South America, 

 to judge from Bates^s fascinating description of '^ the asso- 

 ciated bands of insect-eaters'^ of the forests of the upper 

 Amazons. Here " numbers of distinct species, belonging 

 to many different families, join together in the chase or 

 search for food" ; and " One may pass several days without 

 seeing many birds ; but now and th?U the surrounding 

 bushes and trees appear suddenly to swarm with them. 

 There are scores, probably hundreds of birds, all moving 

 about with the greatest activity — Woodpeckers and Dendro- 



