6 ARKIV FÖR ZOOLOGI. BAND 13. N:0 4. 



Sennorita. 



San Elmo (partly) 



Cangrejo. 



These are mainly inhabited by sea- or shore birds, viz., 

 Sula, Phalacrocorax, Fregata, Pelecanus, and 

 Gu ar a. Also four species of Tyrannids, viz., Camptostoma 

 pusillum flaviventre, Myiodynastes maculatus 7iobilis, Myiarchus 

 ferox panamensis and one Tanager, Ramphocelus dimidiatus 

 limatus were met with in Pacheca, but concerning tlieir breeding 

 in that island there are no statements. 



Also two birds of prey were found here, Catharista urubu 

 and Polyborus cherhvay, but I think they visited the islands 

 only in search of prey. 



2. Islands with tropical forests. 



Most of these islands have a very luxuriant nature and a 

 rich bird life; save for Polyborus cherhvay all the species re- 

 corded from the Archipelago have been taken from one 

 or more thereof. Certainly, water birds such as boobies, cor- 

 morants, man-o' -war birds, and pelicans, which breed in 

 the rocky islands mentioned in the former group, have no 

 breeding places here but good fishing-water on the shores. 

 The biota of these islands is similar; the greatest number of 

 species has been collected in San Miguel, this island also being 

 the largest in the Archipelago. But we must remember that 

 many of the other islands were visited only for a very short 

 period, so the number of species occuring there might possibly 

 be a greater one. 



III. The relation between the bird fauna of 



the Pearl Islands and that of the main- 



land of Panama, 



With regard to the situation of the Pearl Islands, it is 

 to be expected that their bird fauna must be very nearly 



