The Role of Saliva in Food Storage by the Gray Jay

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Abstract
A pair of greatly enlarged salivary glands has been described in jays of the genus Perisoreus. Observations were made of captive gray jays (P. canadensis) to determine the function of the saliva. Jays were unable to procure food by tongue probing. Food was manipulated with the tongue and saliva-covered boli were produced. The boli were then stored, mainly above the ground, and the saliva served to fasten them to conifer needles and other parts of trees. Some food was buried but this has not been recorded in nature. Food storage is probably mainly adapted to the hoarding of meat taken from carcasses which become available for short periods throughout the winter. The habit of storing food above the ground and the copious saliva secretion from the enlarged glands may have been the major adaptations enabling the species to occupy the boreal regions during winter.