from the GNU version of the Collaborative International Dictionary of English
- n.pl. A division of passerine birds in which the vocal muscles are but little developed, so that they lack the power of singing.
from The Century Dictionary and Cyclopedia
- In Cabanis's classification (1842), an order of insessorial birds, consisting of a majority of those non-oscine forms which had been called Picariœ by Nitzsch, having ten primaries, the first of them well developed, and the feet neither zygodactyl nor anisodactyl.
- The gallinaceous birds, or Gallinæ: so called from the crowing or clamoring of the males, especially as instanced in domestic poultry.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. used in some classification systems; a suborder or superfamily nearly coextensive with suborder Tyranni; Passeriformes having relatively simple vocal organs and little power of song; clamatorial birds
Sorry, no etymologies found.
 _Latrant homines, non loquuntur_ is his strong expression, and in another place he calls the modern speakers _clamatores non oratores_.
The next period shows us the culmination, the short bloom, and the sudden fall of national eloquence, when with the death of Cicero the "Latin tongue was silent,"  and as he himself says, _clamatores_ not