134 
POPULAR HISTOEY OF BIRDS. 
of moduiations. Mr. Bartram^ in a letter to the American orni- 
tliologist"^^ points out this bird as one of the most useful 
agents in the economy of nature^ for disseminating forest- 
trees^ and other nuciferous and hard-seeded vegetables on 
which they feed. Their chief employment during the au- 
tumnal season^ is foraging to supply their winter stores. In 
performing this necessary duty^ they drop abundance of seed 
in their JBight over fields^ hedges^ and by fences^ where they 
alight to deposit them in the post-holes, etc. It is remark- 
able what numbers of young trees rise up in fields and pastures 
after a wet winter and spring. These birds alone are capable, 
in a few years^ time, to replant all the cleared lands.^^ 
Among the numerous islands of the Rio Negro, Mr. Wal- 
lace fell in with a very curious bird of this family, called the 
Umbrella-bird^^ {Cepkalopterus ornatits). It is about the 
size of a raven, and, like it, is black ; the male in particular 
has a singular crest on its head, formed of feathers more 
than two inches long, very thickly set with hairy plumes, 
curving over at the end. These can be laid back so as to 
be hardly visible, or can be erected and spread out on every 
side, forming a hemispherical dome, completely covering 
the head, and even reaching beyond the point of the beak/^ 
* Quoted in 'American Ornithology/ vol. i. p. 259, 
