do blue jays eat bird eggs

It was the morning after another recent, successful spring owl migration night, bringing our total for that week to 20 caught, banded and released.

But now with the owls probably all sitting well camouflaged in treetops, I was focused on the birds inhaling sunflower seeds at my feeder. At times, there would be six of them on the feeder downing 10 to 15 seeds each before they flew off.

Although blue jays do eat insects, and occasionally other bird eggs and nestlings, their diet mostly is seeds and nuts, with sunflower seeds many of us put out, along with acorns they find in the wild, being major contributors to their diets. I’ve not seen it, but apparently they can stash five or more acorns in their throat pouch and mouth. I assume they are small ones, not the big ones I often see.

While many people do not like blue jays for this hog-like eating behavior, I find them quite interesting. But I’m also disappointed I have not given more serious thought before as to how they are digesting all of those seeds.

Thinking about it more than I previously had, I was quite sure they weren’t cracking the sunflower seeds open and hulling them as they put them in their mouths. So, I initially assumed they must just swallow them and leave it up to their muscular gizzard, loaded with gritty sand, to break them open for further digestion. But that didn’t seem to make sense either, so I went online and got mixed info from different sites.

I then decided to reach out to the two other nature columnists who write for the Star Tribune, Val Cunningham and Jim Williams. For the past couple years, I’ve tried to read Wednesday and Sunday morning editions, where one of them usually has a column in the E section. I’ve also communicated with them on stories we write, or vice-versa.

Val responded quickly. “I’d say that blue jays fill up their throat pouch with sunflower seeds, then fly off to hide them in a cache to eat later, or cough them up one by one to eat, after pounding open the shells, as opposed to swallowing them whole.”

She then checked with another birding resource she relied upon and confirmed that seemed to be what they do.

I was kind of surprised, as I’d seen hundreds, perhaps thousands, of blue jays feeding during the years, but don’t recall observing any of them displaying this behavior. I have, however, watched many chickadees take a single sunflower seed, fly a short distance from the feeder, transfer it to their toes and then tap it until it breaks open. Guess I will need to watch blue jays more closely to witness them doing it for the seeds they temporarily store in a throat pouch.

Although having a reputation as being an aggressive feeder bird, blue jays are not as aggressive as other birds. For instance, I often have seen red-bellied woodpeckers on the feeder that seem to display dominance over blue jays on the same feeder.

Among their own kind, blue jays have quite complex social interactions, using both sounds and the raising of feathers on their crown to communicate. The higher up the crown, the more displeased they are. But they also are very committed, usually developing year-round, lifelong bonds with their mate.

And, even though their name implies they are blue, blue jays actually are not. The blue color we see is not because of a pigment, similar to the red in cardinals, but instead, the color is caused by microscopic structures in the feather that refract light similar to a prism, often referred to as iridescence.

Blue jays are vocal birds, able to squawk, but also able to mimic other birds, something I attribute to them being quite smart, since they are close relatives of crows. I can’t count how many times I have heard what I thought was a red-tailed hawk calling, only to have it turn out to be a blue jay.

Although I consider blue jays to be year-round resident birds, some actually do migrate. And, even though quite large, blue jays can be picked off by the small woodland sharp-shinned or Cooper’s hawks, or by cats that humans allow to run free.

So, don’t begrudge blue jays inhaling your seeds, as they, too, must eat. And, make sure to keeps your cats from feeding on them. Share Share this article

There is a pair of blue jays that comes daily. But they never visit the feeder with millet or sunflower seeds. Instead they always want nuts.

If they are finicky eaters, where does a bird of that size find enough food to eat?

Blue jays are not as aggressive as other birds, despite their reputation as being aggressive feeders. For example, I frequently observe red-bellied woodpeckers on the feeder, who appear to be dominating blue jays there as well.

But now that I was concentrating on the birds at my feeder ingesting sunflower seeds, I doubt that the owls were all sitting comfortably concealed in the treetops. There would occasionally be six of them on the feeder, and they would each consume ten to fifteen seeds before taking off.

I then made the decision to get in touch with Jim Williams and Val Cunningham, the other two Star Tribune nature columnists. I’ve been making an effort to read the Wednesday and Sunday morning editions for the past few years, and one of them typically features a column in the E section. We’ve also exchanged messages about stories we write together, or vice versa.

While I believe that blue jays are year-round residents, some of them do migrate. Furthermore, despite their size, blue jays are vulnerable to being killed by domestic cats or by small woodland sharp-shinned or Cooper’s hawks.

While they do occasionally consume insects, other birds’ eggs, and nestlings, blue jays primarily consume seeds and nuts. Acorns that they find in the wild and the sunflower seeds that many of us scatter are the two main sources of food for them. Although I haven’t witnessed it, it seems that they can store five or more acorns in their mouth and throat pouch. I’m assuming they’re smaller than the large ones I frequently see.

FAQ

Do Blue Jays destroy other birds eggs?

Thief!” the bird making the noise is the Blue Jay. This noisy, active bird is often known for stealing and eating eggs and nestlings of other birds and pestering predators such as house cats, owls, and red-tailed hawks.

Will blue jays eat baby birds?

Usually they limit their predation to stolen eggs and the occasional baby bird, but they also readily devour larger insects like cicada and grasshoppers if they see them. I once saw a Western scrub jay with a very small mouse, and I suspect they are opportunistic carnivores mostly.

What are the predators of the baby blue jays?

Adult blue jays are often preyed on by various species of hawks, owls, and falcons. Nestlings are preyed upon by squirrels, cats, snakes, American crows, other jays, raccoons, opossums, and birds of prey, such as hawks.

How long does a Blue Jay sit on her eggs?

Clutch Size:
2-7 eggs
Egg Width:
0.7-0.9 in (1.8-2.2 cm)
Incubation Period:
17-18 days
Nestling Period:
17-21 days
Egg Description:
Bluish or light brown with brownish spots.