9 February 2023

Nuts seem an unlikely food for blue jays but in fact they make up 67% of their diet in winter. Acorns are their favorites but they also eat beechnuts, chestnuts, hickory nuts and hazelnuts depending on availability.

Jays pluck acorns from the trees in autumn and eat them on site or cache them for later consumption. You would think acorns are too hard for a blue jay to open but Birds of the World (Cyanocitta cristata) explains how they do it:

Hard foods such as acorns, dry dog food, eggs, etc., are rendered by holding them against a branch or other substrate with one (usually) or both feet, and hammering with the mandible. 

To cache the nuts — as much as 2.5 miles away — blue jays stuff their faces. The blue jay at top is carrying two acorns in his throat and one in his beak. The blue jay below is going overboard with peanuts. When they reach their cache sites they dump the nuts in a pile and bury them individually.

Blue jays have a great memory for where they’ve buried nuts but they stash so many that they inevitably lose track of a few.

If they don’t retrieve all of them, no problem. The acorns germinate and become new trees. Studies have shown that “This tendency may account for the rapid post-glacial dispersal of oaks indicated by pollen analysis,” according to Birds of the World. With this in mind, the Agassiz Audubon Society in Minnesota enlisted the help of blue jays ten years ago to “plant” oaks after volunteers collected and dispersed thousands of native acorns in an area that needed new trees.

To retrieve their cached food, blue jays dig it up with their beaks but this doesn’t work when the ground is frozen. It’s just one more reason why blue jays migrate south for the winter.

If your neighborhood doesn’t have any blue jays right now, it may be because they migrated. But check out the local trees. If there aren’t any oaks or nut trees in your neighborhood that may explain why you haven’t seen any blue jays lately.

This vintage article still gets a lot of comments because people miss seeing blue jays.

Have You Seen Any Blue Jays Lately?

(top photo by Christopher T via Flickr used by permission. Remaining photos from Wikimedia Commons; click on the captions to see the originals)