*S1, aviary section in which cumulative mortality rate could not be estimated because exact bird population was not known and birds were difficult to observe; S2, aviary section in which captive bird population was exactly known and number of dead birds was precisely recorded; NP, species not present in S1 or S2.
†Only sample that was negative for highly pathogenic avian influenza virus (H5N1); all other birds sampled were positive.