- Education and Science»
- Life Sciences
The Northern Blue Jay: The Other Blue Bird
Blue Jay in Summer
Blue Jay Facts
Diet: Omnivore – seeds, insects and berries
Life span: The longest known life spans are 17.5 years in the wild and 26.25 years in captivity. The average wild life span is believed to be 7 years.
Size: 10 to 12 in (25 to 30 cm)
Weight: 2.5 to 3.5 oz (70 to 100 g)
Habitat: Forests dwellers, but also live in suburban neighborhoods, cities and parks
Observing Blue Jays
Last spring that loud cry from my backyard came again, and I dismissed it because I had NOT forgotten to feed the birds that morning. that bully had no business fussing at me. Then I went to the back window to see what was going on. The White-wing Doves were cooing up in the Mimosa tree on one side like usual. At the top of the tree stood my neighborhood Blue Jay making frantic calls like Paul Revere on his night ride to Concord. Considering the time of year, I imagined it a jubilant announcement that his nestlings had hatched.
Northern Blue Jays are likely the second most widely known backyard birds east of the Rockies along with to the Cardinal. Their brilliant blue feathers, speckled wings, raised crest and black necklace make them easy to see, even in dense bush. The pigment in Blue Jay feathers is actually melanin, or brown. The blue we see is caused by modified cells on the surface of the feather barbs that scatter light. The black bridle across the face, nape, and throat (necklace) seems to be unique to each bird, which may help Jays recognize one another.
How to Tell Male and Female Blue Jays Apart?
Long time birders will laugh and say, “Only the Blue Jays know.” The truth is, the males are a little bigger, but it’s hard to tell by size. The main difference is in social behavior. In February, love is in the air for these birds. If you see a group of Blue Jays, watch to see who leads. Courtship involves a flock of males following a single female from place to place. When perching, the males will be bobbing their heads and striking poses. The winner of this beauty contest gets the girl.
If you observe these birds at nesting time, you will notice that both bring nest materials and build, but Blue Jays will build a few practice nests before the final one. When the final nest is built, the female will do most of the work. She will also do all the incubation while the male defends the nest and brings food. If you see a cat, dog or squirrel getting chased by a Blue Jay, it will likely be the male because the animal came too close to the nesting site.
Blue Jay Backyard Feeding Basics
If you put out water and feed where a large bird can get to it, they will come. A Blue Jay’s wild diet includes nuts, seeds and berries depending on the availability. They also are known to go after a wide variety of insects. Bringing Mr. Blue Jay into the yard is a great thing for gardens. I have also heard reports of Jays taking off with wasp nests to feed their young in spring.
Blue Jays aren’t very picky when it comes to bird feed. They like sunflower seed and some mix seed feeds, but once you put out the nuts; they may not want anything else. Laying out a nut mix or even peanuts in the shell will bring them in quick.
A Little Something Extra A negative some people may hear is that, on occasion, Blue Jays will eat other small nesting chicks and eggs. This is true, although it is rare. Studies have been made showing that only about 1% of Blue Jays do this. Female Blue Jays and other birds need calcium in the spring and both sexes can use extra minerals in the fall. Whether or not it will save a nest, giving your Blue Jays some calcium as extra feed would not go amiss.
- Save eggshells after cooking, rinse them out and bake them in the oven at 250 degrees for 20 minutes. This cleaning and baking eliminates harmful bacteria.
- Crush the eggshells and place them on your feeder or on a separate tray if you want to see how it is received.
Blue Jay Bathing
Do Blue Jays Migrate?
Blue Jays are one of those birds that may or may not be migratory, but are listed as such. I see them year round as I live in the subtropical areas of Texas. But in late October through mid-January they seem to disappear or visit very rarely. In more northern climates, they are seen migrating in flocks as large at 250 or more, but it seems to be a matter of choice. Some will stay in the area they hatch all year and some will migrate one year and not the next.
As mentioned, Blue Jay courtship starts in February. A pair will build a few practice nests and then build the final one within a week between 10 to 25 feet off the ground in the thick outer branches of forest trees. They will have 2 to 7 bluish or light brown eggs with brownish spots. Incubation takes about 18 days.
Between 17 and 21 days old nestlings can wonder away from the nest on trial trips up to 15 feet before they fledge. After fledging, young birds will stay with their parents for a month to two months.
There is a wide range in times recorded for nesting, fledgling and parenting. Blue Jays vary in how they deal with their young. In Southern climates, a pair may have two broods, so spacing between broods may be involved.
Nest Platform, Not Box
In cities and suburbs, Jays will also nest on the ledges of buildings. Because they prefer open nesting, they won’t be tempted by a nesting box. If you want to host a nesting pair you need a nest platform or shelf.
Birdhouses101.com suggests “an open birdhouse or nesting platform (or shelf) will surely attract the blue jays. Provide a floor area of about 8 inches by 8 inches with a ceiling also about 8 inches high. A sloping ceiling with open sides and front, (like the Amazon example below,) is ideal. Birds that normally nest on trees are more likely to nest on platforms as well just like the blue jays.”
To mimic the bird’s natural habits, place the shelf on a pole or on the side of a building in a protected place.
Get it Yourself: Platform Nest Example
Jays and Their Calls
Despite their reputation for being aggressive, Jays are not the alpha bird. Woodpeckers, Grackles, Mourning Doves, White-winged Doves, Northern Mockingbirds, and Northern Cardinals and squirrels seem to be above them in the feeder pecking order.
In response, Jays have developed an extensive vocabulary. Friends with feeders have told me of hawk cries in their yards. When they headed out to investigate, they often only find a Blue Jay making the noise. This mimicking tactic may have been developed to clear the way to food without confrontations. In the wild, their hawk imitations can include Red-shouldered and Red-tailed hawks.
Young Jay Getting a Lecture
If you see a bald Jay, you are seeing a young bird at the end of the nesting season, usually in August. This is normal molting.
Young birds start out life with a head feather pattern reminiscent of helmet. Their first feathers will be replaced in a few weeks with adult feather patterns. Both sexes will lose part or all of their head feathers at this time.
Some people refer to them as skyrockets at this time, because they hide and make very quick dashes to feeders during this time. It is not a well-studied pattern, so how often this happens or what other causes may be involved aren’t known. Lice, mites and nutritional and environmental factors might also cause molting. Cardinals are also prone to going bald during the same time.
Tool Using Birds?
In captivity, Northern Blue Jays have been seen using newspaper strips as tools to move seeds that have fallen outside their cage closer to them. No one has ever reported seeing this in the wild.
Blue Jays are may be loud and vivacious, but they aren’t at the top of the song bird chain, so have developed inventive behaviors to help them out. They can also be inventive in tool use, though this may be rare and due to need. They vary in the way they care for their young and in whether they migrate or not. All this points to the Northern Blue Jay being a very special contrary and lovable bird.
© 2015 Sherry Thornburg