Yucatan Jays are opportunistic omnivores with a diet which varies from season to season and makes use of temporary abundance of food items. Raitt and Hardy (1976) found that in the spring season the contents of stomachs contained about equal plant and animal material. Seeds were found to make up about 68% of the plant material by volume with corn being the most important. As for animal material, arthropods were found to be dominant. Beetles accounted for 19% of the volume of animal food, orthopterans 30% and lepidopteran larvae 17%. Spiders, ants, slugs, dipterans and a slug were also found in the stomachs examined.
In the summer of 1972, it was observed that large numbers of caterpillars were fed to incubating birds and nestlings. Caterpillars filled 40-60% of total stomach contents during this time. In 1973, when caterpillars were low, the jays instead utilized fruit extensively and were observed foraging green papaya fruit from milpas (small farms).
When foraging, these jays will sometimes perch 1-5 m above army ant columns and eat invertebrates flushed by the ants. They will often travel near the forest edge in groups flying and hopping from perch to perch at levels ranging from near the ground to the top of the canopy. They move slowly and deliberately, searching foliage and branches for fruit and insects.
(Above taken from Raitt and Hardy 1976)