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Steller's Jay



Choosing a Mate

Steller’s Jays reproduce sexually by means of an egg.  They do something called sexual sidling to choose a mate.  Sexual sidling is the act of two jays strutting sideways towards each other (Brown, 1963).  Steller’s Jays tend to choose a mate with similar behavioral characteristics.  They choose to do this because it has been found that partner similarity improves reproductive performance (Gabriel and Black, 2012).  These jays are monogamous, meaning they have the same mate for a lifetime (CAC 2013), and after choosing their mate, Steller’s Jay rarely separate. 

Nest PlacementSteller's Jay Perching

When it comes to choosing a place to make a nest, both partners have a say in it.  Both partners choose the site of the nest as well as engage in the building of the nest (AAB 2005).  Steller’s Jays do something with their nest that only one other jay, the Blue Jay, does in North America.  Steller’s Jays use mud to help hold their nest together.  Generally, the nest is built into the shape of a cup, and built with stems, leaves, mosses, sticks, and mud.  The Jays then line the inside of the nest with pine needles, soft roots, or animal hair (AAB 2005).  Steller’s Jays’ nests are often found in conifers on horizontal branches close to the trunk, but they can be found anywhere from the base of the tree to the top of the tree.  They have also been found in the middle of bushes or shrubs very close to the ground (Brown, 1930).  The nest sizes vary from ten to seventeen inches wide, six to seven inches tall, and 2.5 to 3.5 inches deep on the inside (AAB 2005).

Laying Eggs

When it comes to the laying of eggs, the female can only lay one egg per day (ADW 2001), and between two and six in total (Gabriel and Black, 2012).  The eggs are fairly small, being a little over an inch in height and a little under an inch in width, and bluish-green in color with dark brown, purple, or olive colored spots.  The incubation period for Steller’s Jays in about sixteen days (AAB 2005), but just like the finding and building of the nest, both partners participate in the incubatingSteller's Jay looking for predators of the eggs.  Females do the majority of the work, but some males have been seen incubating eggs (ADW 2001).  After the Steller’s Jays hatch, they have a sixteen day nestling period, meaning they stay in the nest for sixteen days (AAB 2005).  Generally, their feathers grow in about seventeen days (Gabriel and Black, 2012), and they are capaable of flying three weeks after birth (CAC 2013).                             

Protecting the Territory     
Steller’s Jays are protective of their nests and the surrounding territory, and they will even attack other jays in their territory (AAB 2005).  When Steller’s Jays have to deter a predatory bird, they perform a defensive strategy called mobbing (ADW 2001).  Mobbing occurs when a flock of Steller’s Jays fly aggressively toward a predatory bird like a Cooper ’s Hawk, one of the jay's main predators (ADW 2001), in order to protect their territory as well as their young (CAC 2013).  Steller’s Jays are a very social group of birds, and often form flocks.  In fact, Steller’s Jays sometimes form mixed-species flocks (AAB 2005).  These birds live a fairly long life, spanning about ten years (CAC 2013).  The oldest Steller’s Jay on record lived for sixteen years and one month (AAB 2005).

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