The Collaborative International Dictionary of English v.0.48:

Bird pepper \Bird" pep`per\
   A species of capsicum (Capsicum baccatum), whose small,
   conical, coral-red fruit is among the most piquant of all red
   peppers.
   [1913 Webster]

WordNet (r) 3.0 (2006):

bird pepper
    n 1: plant bearing very small and very hot oblong red fruits;
         includes wild forms native to tropical America; thought to
         be ancestral to the sweet pepper and many hot peppers [syn:
         bird pepper, Capsicum frutescens baccatum, Capsicum
         baccatum]