Associations between seabirds and cetaceans are common. To describe the presence of associations among Delphinus sp and seabirds in the Mochima national park, from October 2009 to September 2010, observations of groups of this cetacean and seabirds were made on mobile platforms, using a focal group-follow methodology. Data such as dolphins group size, behavior, flock type, flock size, species were collected. univariate chi-square test, contingency tables and the Sperman correlation
test were used to analyze the data. Out of 86 dolphin groups observed 54 (62.79%) were associated with
seabirds. The most frequent seabird species in these associations was the Brown booby (Sula leucogaster)
(63%), followed by the Brown Pelican (Pelecanus occidentalis) (15%), the Magnificent Frigatebird (Fregata magnificens) (8%), the Masked Booby (Sula dactylactra) (7%), and the Neotropic Cormorant (Phalacrocorax brasilianus) (7%). There were statistically significant associations between dolphin behavior and flock type (χ2 = 14.51, df = 1, p-value = 0.00013). We observed that the size of dolphinassociated bird flocks tended to increase with the size of dolphin schools (Spearman rank correlation = 0.53, p-value = 4.294e-05). These associations often play an important role in foraging success in tropical regions. It has been suggested that these interactions may increase bird foraging efficiency and decrease energy expenditure, although there is no apparent benefit to dolphins.
