134 BROOKLYN INSTITUTE MUSEUM. SCIENCE BULLETIN 2. 6. 
species actually represented in the Brooklyn Museum collections 
included, but also all additional forms that were collected or observed 
on my first expedition to the Orinoco ; while, to make the paper more 
complete, and particularly in the interest of those who may not have 
access to Berlepsch and Hartert's paper "On the Birds of the Orinoco 
Region,!" there are added all species from the Orinoco proper, and 
its tributary the Caura River, included in that paper, but not ob- 
served by the writer. Also, species that ha\-e been recorded from the 
Orinoco region, since the publication of Berlepsch and Hartert's paper, 
and that have come to the notice of the writer are included. 
Where colors are given of the eye and naked parts about the head, 
of the bill, and of the feet, they are the result of a direct comparison 
with the colored plates in Ridgway's "Nomenclature of Colors" and 
were made in the field from freshly killed specimens. 
For almost all groups "keys" for the more ready determination of 
the various genera, and their species, have been inserted, following the 
preliminary observations under each of the family headings. Many of 
these keys, with slight alterations, were prepared by the writer for his 
convenience in the identification of specimens in the field. And while 
the keys were constructed primarily as aids in identifying the species 
known to inhabit the immediate valley of the Orinoco, there are 
frequently included the necessary "characters" distinguishing many 
species known to be found in contiguous territory. It must be under- 
stood, however, that no effort has been made to supply "keys" to the 
birds of other regions of northern South America. 
The nomenclature and determination of species is much the 
same as that employed by Berlepsch and Hartert in their pajjer 
which was based chiefly on the collection made in the same region by 
Mrs. Cherrie and myself in 1897 to 1899, and the Andre and Klages 
collections from the Caura River district. 
The references to Berlepsch and Hartert. unless specifically noted 
to the contrary, are to their paper, and the nomenclature where not 
otherwise indicated is the same. 
TURDIDAE— THE THRUSHES. 
Six thrushes are found on the Orinoco : five are resident forms of 
the genus Planesticus and one a North American migrant of the genus 
Hylocichla. The latter is probably never found in juvenal plumage 
>Novitates Zoologicae IX. 1902. p. 134. 
