Male blue jays tend to be larger in size than females, but since males and females share the same plumage, it is difficult to tell them apart by size alone. Careful observation of courtship and nesting behavior is the best way to tell the sexes apart. Blue jays are large songbirds often identified by their blue bodies and head crests, or sometimes by their noisy calls. Their unmistakable plumage includes various shades of bright blue on their wings and tails, white or grey underparts, white patches on the wings and tail and a dark band around the neck, known as a necklace. Blue jays are known for their intelligence. Their social, mating and nesting behavior indicates tight family bonds.

Courtship and Mating Behaviors

Careful observation of behavior is the only way to positively identify male from female blue jays. Blue jays are often seen in courtship groups of three to ten blue jays. In these groups, a single female blue jay determines the behavior of the surrounding males. For example, if a female begins to fly, the males follow; when the female lands, the group of males also land. After landing, the female blue jay will observe while the males bob their heads and fluff their feathers in attempts to attract the female.

Nesting Behaviors

Males and females behave differently during the nest-building period, which takes about a week. Both the male and female blue jay will share responsibility at first while building practice nests. However, the female does most of the work of work in building the actual breeding nest. The female also does most of the incubating of the pair’s eggs while the male blue jay will bring food to the female.