They don't necessarily eat what they take right away. If they are by themselves when they find food, they often will hide it nearby, for eating at a later date. Interestingly though, if they find food that has been found by other animals as well, they will carry it a greater distance away, in order to conceal it from something else that may be watching.
I firmly believe that they keep a close eye on other Whiskeyjacks, other birds, animals, and people, in order to find food. If one happens by something good to eat, it won't be long before you will have many more snooping about.
Also, interestingly I have learned the origin of the name Whiskeyjack. It has confounded me up until now, how a bird could be named such a thing.
Wikipedia makes it clear:
"Wisakedjak (Wìsakedjàk in Algonquin, Wīhsakecāhkw in Cree and Wiisagejaak in Oji-cree) is the Crane Manitou found in northern Algonquian mythology, similar to the trickster god Nanabozho in Ojibwa aadizookaanan (sacred stories) and Inktonme in Assiniboine myth. He is generally portrayed as being responsible for a great flood which destroyed the world originally made by the Creator, as well as the one who created the current world with magic, either on his own or with powers given to him by the Creator for that specific purpose. His name is subject to many variant spellings, including Weesack-kachack, Wisagatcak, Wis-kay-tchach, Wissaketchak, Woesack-ootchacht, and undoubtedly others. It was sometimes Anglicized as Whiskey Jack, which became an alternate name for the Gray Jay."