observed during the Voyage of the 'Valhalla.' 681 



A very common bird on Mayotte, especially on the cleared 

 portion of the island, where there are a few trees standing. 

 Most of my specimens had light blue-green feathers scattered 

 over the plumage of the upper parts. This species has a very 

 wide range (E. and N.E. Africa, S.W. Africa, Madagascar, 

 and the Comoros). 



Cypselus mayottensis. 



Cypselus mayottensis Nicoll, Bull. B. O. C. xvi. p. 104. 



One pair and one example of uncertain sex. 



In Mayotte Harbour there are numerous little islets scat- 

 tered about, and one of these, Buzi by name, we visited. 

 Several Swifts were noticed flying about, and I managed to 

 shoot three of them. To my surprise they appeared to 

 belong to an undescribed species, which in colour approaches 

 C. sladena, but is much smaller, especially as regards the 

 wing. Moreover, my specimens are smaller than C. barbatus, 

 which species they also approach somewhat in colour. The 

 general tint of the upper parts is deep bluish green, the 

 chin and throat are streaked with brown on a dirty grey 

 ground, and the rectrices have a distinctly blue sheen 

 or gloss. 



Tachornis gracilis (Sharpe). 



Tachornis gracilis Hartert, Cat. B. B. M. xvi. p. 464. 



One female. 



This little Swift was not numerous on Mayotte. I saw a 

 few at the edge of the forest and others flying over the 

 mangrove swamps. The flight of this species is very rapid, 

 and it is therefore by no means easy to shoot. It has a 

 wide range (W. Africa, E. Africa, and Madagascar). 



Ealco subbuteo Linn. 



Falco subbuteo Sharpe, Cat. B. B. M. i. p. 395. 



A perfectly adult male Hobby flew on board one evening 

 when we were lying off Mayotte and was caught and brought 

 to me. 



Astur pusillus Gurney. 

 Astur pusillus Gurney, Ibis, 1875, p. 959. 

 ser. viii. — VOL. vi. 2 Y 



