POTENTIAL ROLE OF CATTLE EGRETS, BUBULCUS-IBIS (CICONIFORMES, ARDEIDAE), IN THE DISSEMINATION OF AMBLYOMMA-VARIEGATUM (ACARI, IXODIDAE) IN THE EASTERN CARIBBEAN

The potential role of cattle egrets, Bubulcus ibis (L.), in the dissem ination of Amblyomma variegatum (F.) in the eastern Caribbean was eval uated. The status of cattle egrets as hosts for A. variegatum in Antig ua was determined during seven survey periods between September 1988 a nd May 1991. The mean prevalences of infestation by larvae and nymphs were 2.3 and 0.5%, respectively. The mean intensity and relative densi ty of infestation by larvae were 8.8 (SD = 9.80) and 0.2 (SD = 0.28), respectively. Cattle egrets examined in Guadeloupe during February-Mar ch 1991 were not infested but 5.9% were infested by larvae during June -July 1991. Interisland movement of cattle egrets was evaluated relati ve to emigration of birds captured and marked in Antigua and Guadeloup e. During this aspect of the study, 1,129 cattle egrets were captured, marked, and released. Of 195 sighting reports received, 56 were deter mined to be independent sightings. Emigration of cattle egrets include d movement of birds marked in Antigua or Guadeloupe to 14 Caribbean is lands and the Florida Keys. Interisland movement occurred in each of t he discrete observation periods during the 3-yr study period. The rate of emigration per period ranged from 1.2 to 12.9%. That cattle egrets served as hosts for immature A. variegatum in the eastern Caribbean a nd moved between islands in the region demonstrates that these birds c ould serve as disseminators of the tick. Estimates of the numbers of i nfested cattle egrets emigrating from Antigua and Guadeloupe ranged fr om 0 to 0.24% of the current populations.