313 



H^MATOPUS. 



Subspecific 

 characbers. 



Geographi- 

 eal distribu- 

 tion. 



The South-American Black Oystercatcher only differs from its more northern ally in 

 having generally a shorter and deeper bill. Examples in my collection of the northern form 

 have bills 3j inches in length and 0"5 in. in depth, whilst others from Chili have bills 

 2f in. in length and 0'6 in. in depth. It is said, however, that in a series of each the 

 dimensions are found to overlap, so that American ornithologists very justly regard the 

 two forms as only subspecifically distinct. 



Like its representative in the Northern Hemisphere, it appears to be confined to the 

 Pacific coast of the American continent, except that its range extends through the 

 Straits of Magellan to the Falkland Islands. It is doubtful whether it has ever occurred 

 north of Chili, nor is there any evidence that it is a migratory bird. Two examples from 

 Callao and one from MoUe in South Peru in my collection appear to be somewhat 

 intermediate, the bills being long like the North-American form, but deep like the South- 

 American form. The bill of one of the Callao birds is represented in the upper figure of 

 the woodcut. 



