MEROPS BULLOCKOIDES. 



DIMENSIONS. 



Inches. Lines. 

 Length from tlie tip of the bill to the 



point of the tail 7 6 



ofthetail 4 



of the bill from the angle of 



the mouth 1 7 



Inches. Lines. 



Length of the wings when closed 4 6 



of the tarsus 3^ 



of the middle toe 3 



of the hinder toe 2 



The female resembles the male, with the exception that the colours are not 

 quite so bright. 



Between this species and Merops BuUockii many discrepancies might be 

 instanced, but the diagnostic character, which will prove the most readily 

 available, is the colour of the upper tail coverts. In the present species, this 

 colour is invariably similar to that of the lower ones, whereas in Merops 

 BuUockii it is very different. 



It was not until the expedition attained the 25° of south latitude that this bird was disco- 

 vered, though north of that it appeared not uncommon. When observed, it was generally 

 either perched upon the tops of trees, along the immediate banks of rivers, or in the act of 

 making short circuits through the air, apparently in chase of flying insects. As may be infer- 

 red from the structure of its wings, it is not a bird which flies for any great length of time 

 without resting ; it seeks its food during frequent low and short flights, and after each of these, 

 often returns to the perch from whence it proceeded. In respect of its habits, as well as its 

 wings, it closely resembles Merops Erythropterus, Lin. ; but, in regard to both these characters, 

 it differs from the other species of the genus yet observed in South Africa. Upon the modified 

 structure of the wings in this species and M. Erythropterus may depend the circumstance of their 

 being permanent inhabitants of the districts where they are found, and where they encounter 

 a cold during the winter much more severe than ever occurs farther to the southward, and from 

 which the Merops Apiaster, Lin. M. Savignii, Levaill. and M. chrysolaimus, Jard., fly towards 

 the end of summer. From observations I have had occasion to make, I think it probable that 

 the migrations, both of birds and quadrupeds, will be found often to depend more upon causes 

 which have hitherto been comparatively overlooked, than upon any absolute deficiency of food 

 in the countries from whence they retire. Connected with this opinion, I may instance the cir- 

 cumstance of a species of swallow, which inhabits the mountains of the Cape Colony during 

 the summer months, repairing in the winter to the vicinity of houses left, by another species, 

 on the approach of the cold season. It there finds food suSicient for its support, till the other 

 species, gifted with more vigorous powers of flight, and a superior courage, returns and drives 

 it back again to situations which it had for a time abandoned. 



