Lewis & Short

occĭno, ŭi (perf. occecini, Liv. 6, 41, 8: occanui, Serv. ad Verg. G. 2, 38, 4), 3, v. n. [ob-cano].

  1. I. To sing or chirp inauspiciously, to croak, etc. (not in Cic. or Cæs.): si occinuerit avis, i. e. if by its chirping it gives an unfavorable omen, Liv. 6, 41, 8: corvus voce clarā occinuit, id. 10, 40 fin.: occinentes in eum adversum corvi, Val. Max. 1, 4, 2.
  2. II. In gen., to sing, chirp, cry: animalia inter se, App. Flor. p. 349, 20.