Laura Erickson's For the Birds

What do Blue Jays eat? In the past month, people have reported to me that their backyard jays are eating small birds killed at windows and roadsides, mealworms and other insects, dog food, sunflower seed, cracked corn, fruits on trees, acorns, and peanuts. In the past I’ve observed them feeding on road-killed carcasses, beechnuts, walnuts, peanut butter and peanut butter crackers, and eggs and baby birds—well, I haven’t seen adults eat these last two but I have seen them feed them to their babies. Some studies have shown that the adult Blue Jay diet is about 88% vegetal, and based on the amount of sunflower seeds I’ve seen them pack away in a single sitting, that seems about right.

When I took care of injured and orphaned jays as a licensed rehabber, I found that they like a lot of variety in their diets, and seemed especially fond of some items, like ice cream, Froot Loops ®, canned dog food, cottage cheese, hardboiled eggs, walnuts, acorns, and peanuts. Back then, if someone had asked me what a Blue Jay’s favorite food of all was, I would have said strawberry ice cream, because the jays I cared for gobbled that down so very fast when it was offered. But that may well have been because they’d figured out that ice cream doesn’t last very long before it’s a goopy mess. When I would feed Blue Jays, some days they’d go straight for one item and not another, while other days they might do the exact opposite. I think the way Blue Jays achieve a relatively balanced diet in nature is to select different items from day to day, quickly growing tired of one thing and moving on to others.

Even though variety seems very important to jays, there were some food items that they hardly ever ate. I’d see them take corn but not peas, scoop out every trace of egg yolks while leaving the whites intact, and pick the raisins out of cereal while ignoring the bran. Even though I noticed what they shunned, I never actually conducted a taste test to figure out what their true favorites were. But this fall my good friend and neighbor Mary Tonkin had a Blue Jay coming consistently to her backyard and tried a little taste test on him.

From spring through fall, Mary’s jay comes to the deck railing and peeks into the window waiting for Mary or her husband Bob to set out peanuts. It’s always fun watching jays take peanuts. They pick up several, seeming to weigh each one carefully before selecting one to carry off. Peanuts don’t grow in Minnesota, so Blue Jays have no sources for them except people.

Blue Jays also love acorns. Our neighborhood doesn’t have many oak trees, but Mary gets supplied with acorns every fall from relatives who live in an oak-rich part of Minnesota. When she gets a supply each fall, the jays seem to like them every bit as much as peanuts.

But which do they like better? This year, to find out which the jays really do prefer, Mary started setting out peanuts and acorns together on the deck railing, alternating them one by one. And, one by one, the one the jays picked out all the acorns before touching the peanuts.

Does that really mean that jays prefer acorns to peanuts? Mary and I aren’t sure. In our neighborhood, the jays get peanuts from at least two sources, since I set them out, too. But around here there are no other sources of acorns. So it may simply be the need for variety that impels the jays to pull out the acorns first. I rather think that someone living in an area with a lot of oak trees would get the opposite result, but I’m hardly going to move away from Peabody Street to find out. But if any readers who live near oak trees want to test this theory and report back to me, I’d love to hear from you.