Why so many Blue Jays this winter?

Lorraine Julien | Mar 12, 2014

There was a very prophetic article in the Arnprior Chronicle-Guide last fall. At that time, the author, M. Runtz, noted there were large numbers of Blue Jays in the Ottawa area (the birds, not the baseball players!). Runtz predicted that many jays would stay for the winter because of the huge crops of acorns last year. How true! Although we always have a good number of jays at our winter feeders, there seems to have been a population explosion this winter.

If you were anywhere near oak trees late last summer, you may have noticed all the acorns falling from the trees – a favourite food of Blue Jays. I know that late last summer when working in the garden, I joked that I should have worn a hard hat as we were constantly bombarded by these little missiles. It seemed as though the squirrels were sitting and laughing in the oak trees, literally throwing handfuls of acorns at us with deadly accuracy. At the time I thought there’d be lots of food for many of the animals and birds (especially wild turkeys), but I forgot how much the jays love acorns as well.

When acorns are plentiful, a single jay can stow away as many as 1000 of them. This remarkable trait has been suggested as being responsible for the rapid recolonization of the northeast by oak trees after the glacier period. Oaks spread north much faster than other hardwoods, likely because jays helped them on their way.

It has been unusual to see so many jays as, most winters, a number of them fly south (usually young birds and probably less than 20%). Jays have a large range from southern Canada to Texas and Florida and are classified as being “partially migratory”, particularly in the northern parts of their range.

Following are some interesting Blue Jay facts:

Blue Jay feathers are not actually blue. The bright cobalt colour is the result of a unique inner structure of the feathers which distorts the reflection of light off the bird, making it look blue.

The black bridle across the face, nape and throat varies extensively and may help Blue Jays to recognize one another.

The oldest known wild, banded Blue Jay lived to be more than 17 years old.

Blue Jays have a wide variety of vocalizations and are very good at mimicking other birds, particularly the Red-shouldered and Red-tailed Hawks and sometimes other species. They like to do this when approaching feeders – this may deceive other birds into scattering, thereby letting them take over the feeders. Most other birds return quickly to the feeders, not being fooled for very long.

Adult Blue Jays are known for their unusual moulting behaviour. The birds undergo a complete change of plumage between June and July and are avid “anters” during this period. “Anting” is the process of using ants or other materials to preen or clean feathers. The angry ants release chemicals from their abdomen and these are suspected to keep mites and other feather parasites at bay.

Blue Jays are smart birds: they’ve been known to watch as you plant seeds in the garden and after you leave, they dig them up! Tool use has never been reported for wild Blue Jays, but captive Blue Jays used strips of newspaper to rake in food pellets from outside their cages.

Since Blue Jays are relatively slower flyers, they are easy prey for hawks and owls. I’ve always thought they were raiders of other nests but after the stomach contents of 530 dead jays had been examined, about ¼ of the contents were insects, with the balance made up of acorns, nuts, fruits and grains. Less than 1% had traces of bird remains or egg shells.

Blue Jays communicate with one another both vocally and visually with “body language” using their crest. When incubating, feeding nestlings or associating with their mate, family or flock mates, the crest is held down. The lower the crest, the lower the bird’s aggression level. When a Blue Jay squawks, the crest is almost always held up.

Unlike most other species of birds, males and females are almost identical – the female is a bit smaller.

Although it’s wonderful to see these beautiful blue birds, especially during our long, drab winters, they can become a nuisance when you try to feed other birds. You could try to slow the invasion of Blue Jays to your feeders but you’d have to stop putting feed out for 3 or 4 days (then they’ll go to your neighbours’ feeders!). When you put the feed out again, there should be far fewer jays until word gets out again. As I’m sure you’ve noticed, these noisy birds are great communicators and, where food is concerned, word spreads quickly!