This name occurs in several of the older authors on American Natural
History, which is to be attributed to the fact that the _Whip-poor-will_
(_Antrostomus vociferus_) was regarded by Linnæus as a variety only of
the European Goatsucker. President Jefferson, in Notes on the State of
Virginia, p. 117 (London edition, 1787), gives both of the then known
North American birds of this group as two varieties only of the European
bird. Professor Barton, in Fragments of the Natural History of
Pennsylvania, p. 14, under the head of _Caprimulgus europæus_, says:
“This, or a variety of it, is certainly a native of Pennsylvania. So
that now all the fifteen species of this genus (mentioned by Gmelin) are
known to be natives of America.” Both of these distinguished and
venerated fathers of American zoological science adopted the opinion of
Linnæus, and the name of the European bird is given also on the same
authority by some others of the earlier American writers.
The European Goatsucker has never been observed on the continent of
America.
Professor Barton’s observation above quoted is singularly suggestive.
Linnæus, at the date of his last edition of the Systema Naturæ, knew
_two_ species only of the genus _Caprimulgus_. Gmelin, in the edition of
the same work, edited by him, and published in 1788, extended the list
to _fifteen_ species, and was, when Professor Barton wrote, in 1799,
recent and high authority. So greatly has the knowledge of species of
birds been extended, that at this time (1855) there are at least ninety
known birds of the family _Caprimulgidæ_, all of which would have been
regarded by Linnæus and Gmelin as belonging to the genus _Caprimulgus_.
There are seventy-four species of this family in the collection of the
Philadelphia Academy. Though, as Professor Barton observes, all of those
known to Gmelin (except _Caprimulgus europæus_), are American, others
are now ascertained to inhabit all the temperate and tropical regions of
both of the great divisions of the globe, and the whole of Australia.
Of this family of birds, the only species that have been ascertained or
supposed by naturalists to inhabit that part of North America within our
limits, are given in the preceding pages. The group is, however,
represented in South America not only by other species of the genera
above given, but by various other genera and species, amongst which are
some curious and interesting forms. The genus _Steatornis_, containing a
single species, first brought to notice by the celebrated Humboldt
(_Steatornis caripensis_, Humboldt), is remarkable for its near approach
to the Owls, and would, to a casual observer, scarcely be regarded as
belonging to any other than that family. The genus _Nyctibius_, which is
also South American, contains some species as large as the Crow of the
United States, and which are amongst the largest birds of this group.
Another genus, _Hydropsalis_, or the Scissors-tailed Goatsuckers, as
they are termed by Azara (an enthusiastic and accurate Spanish writer on
South American Natural History), are remarkable for having tails of
singular forms, and of great length in some species. _Hydropsalis
torquatus_ has the two outermost feathers of its tail long, and the two
middle feathers also long, leaving the intermediate comparatively short.
_Hydropsalis lyra_, Bonaparte, has the outermost feathers of the tail
very long, and curved inwards at their ends. Two species, first
described by us, _Hydropsalis limbatus_ and _segmentatus_ (in Proc.
Acad., Philadelphia), have that appendage several times the length of
their bodies.
About thirty-five species of _Caprimulgidæ_ inhabit South and Central
America and Mexico. The largest birds of this group are natives of
Australia.
We are inclined to the opinion that this family (and the Swallows also)
properly belong to the circle of rapacious birds in which they have been
arranged by Prof. Reichenbach, in Avium Systema Naturale (Dresden and
Leipsic, 1850).[4]