salient facts known to us about them I have brought together and put in
order in this place. And I am here departing a little from the plan
usually observed in this book, which is chiefly occupied with matters of
personal knowledge, seasoned with a little speculation; but in this case
I have thought it best to supplement my own observations with those of
others [Footnote: Azara; D'Orbigny; Darwin; Bridges; Frazer; Leotaud;
Gaumer; Wallace; Bates; Cunningham; Stolzmann; Jelski; Durnford; Gibson;
Burrows; Doering; White, &c.] who have collected and observed birds in
South America, so as to give as comprehensive a survey of the family as
I could.

It is strange to find a Passerine family, numerous as the Tree-creepers,
uniformly of one colour, or nearly so; for, with few exceptions, these
birds have a brown plumage, without a particle of bright colour. But
although they possess no brilliant or metallic tints, in some species,
as we shall see, there are tints approaching to brightness.
Notwithstanding this family likeness in colour, any person, not an
ornithologist, looking at a collection of specimens comprising many
genera, would hear with surprise and almost incredulity that they all
belonged to one family, so great is the diversity exhibited in their
structure. In size they vary from species smaller than the
golden-crested wren to others larger than the woodcock; but the
differences in size are as nothing compared with those shown in the form
of the beak. Between the minute, straight, conical, tit-like beaks of
the Laptasthenura--a tit in appearance and habits--and the extravagantly
long, sword-shaped bill of Nasica, or the excessively attenuated,
sickle-shaped organ in Xiphorynchus, the divergence is amazing, compared
with what is found in other families; while between these two extremes
there is a heterogeneous assemblage of birds with beaks like creepers,
nuthatches, finches, tyrant-birds, woodpeckers, crows, and even curlews