Islands of the Coast of Yucatan, fyc. 85 



Summary. 



The apparent number of species found in the islands under 

 consideration thus becomes 215, but from these must be de- 

 ducted No. 52, Hirundo erythrogaster x swainsoni, to all ap- 

 pearance a hybrid; the total thus becomes 214. 



In the list of 214 species, as thus amended, we find the 

 names of 79 which belong to birds which annually migrate 

 from North America to Mexico, Central or South Ame- 

 rica, or the West-Indian Islands, and either reside during 

 the winter months on the islands now under consideration, 

 or rest there during passage in autumn and spring. The 

 only point which I propose to notice in connexion with these 

 migratory species is that we find several that occur here at 

 almost, if not quite, the western limit of their range. The 

 following species come under this category : — Turdus fus- 

 cescens, T. alicios, Protonotaria citrea, Dendrceca ceerulescens, 

 D. discolor, D. palmarum, and Perissoglossa tigrina. The 

 remaining migratory species are birds of wider range, which 

 spread much further westwards in their spring and autumn 

 flight; their presence therefore on these islands is of no 

 special interest. 



Of the remaining 135 species, 27 are birds which fre- 

 quent the sea-coast or marshes adjoining, and are of very 

 wide range, so that their presence also is of no special 

 significance. 



This leaves 108 species, belonging to no less than 84 genera, 

 the distribution of which I propose to examine. They are 

 given in the annexed table (pp. 86-89) . 



Before analysing the list in detail, it is necessary to 

 examine the 32 birds which form the resident fauna of Meco 

 Island. In the first place we find here no less than 9 genera, 

 represented by as many species, which are not found on any 

 of the other islands. All of these genera are characteristic of 

 the fauna of the mainland. Of the species, Phoenicothraupis 

 insularis alone is an island race, and is also found on Mugeres 

 Island. The only species that has any special West-Indian 

 affinity is Elainea martinica, and this is of very doubtful 

 value. 



