Female Mountain Bluebirds (Male vs Female Identification)

The bluest of the bluebirds (in the case of the male), the Mountain bluebird, is widespread throughout the western US and western Canada. This is a guide to female Mountain bluebirds and how to identify them from males.

Female Mountain bluebirds are mostly gray-brown with some blue on their wings and tail. Their breast may also have some blue speckles. The blue tinge to their plumage is easily visible but is nowhere near as bright or conspicuous as the male’s blue plumage.

Male and female Mountain bluebirds form close bonds in the breeding season, and males are often spotted spreading their wings and darting and diving about to attract females. They work together closely throughout the breeding season, with the female handling incubation and brooding and the male handling feeding.

Of course, there are many other differences between male and female Mountain bluebirds - read on to find out!

Close up of a perched female Mountain Bluebird

How can you tell if a Mountain Bluebird is male or female?

Male Mountain Bluebirds are easily identified by their iridescent blue color on the upper body and either white or pale white underside. In contrast, female Mountain Bluebirds are gray-brown with a small quantity of blue on their wings and tail.

It's also possible to differentiate male and female Mountain Bluebirds by their calls and vocalizations. Males have a distinct, almost trill sound to their calls, while females tend to chatter.

Interestingly, males tend to weigh slightly less than females; however, the difference may not be apparent to the naked eye. At close inspection, males may weigh around 0.9 to 1.1 ounces on average, while females can grow up to 1.13 ounces, a very slight difference.

Female Mountain Bluebird

Male Mountain Bluebird

What does a female Mountain Bluebird look like?

A female Mountain Bluebird is similar to a male, except their plumage is significantly duller. More specifically, females tend to have a dull brown color on their upper side, a pale grey underside, and hints of iridescent blue on some parts of their wings or tail.

Females also have brood patches between their legs. The reason for this is females incubate the eggs alone, hence the need for them to shed some feathers to ensure they can provide sufficient warmth for their eggs as they incubate.

Female Mountain Bluebird perched in a tree, Vancouver, Canada

Size Difference

Male and female Mountain bluebirds are near-identical in size and weight. Lengthwise, adult male and female Mountain Bluebirds are the same and can measure between 6.3 and 8.3 inches long.

The only difference is weight, but this is negligible in most cases. With an average mass of up to 1.13 ounces, female Mountain Bluebirds are heavier than their male counterparts by almost 0.03 ounces - a tiny difference - but a difference nonetheless.

A pair of Mountain Bluebirds - female left, male on the right

Behavior differences

Territoriality

Males tend to be more territorial, actively defending their territory from intruders. When they see an intruder, they sing a loud, complex song to indicate their territory. If they sense impending danger, they often issue sharp calls to warn off the intruder and alert their mates.

Females are protective of their nests but aren’t as boisterous or conspicuous as males, especially in the breeding season.

Singing and calls

Male and female Mountain bluebirds communicate avidly with each other throughout the breeding season, but males sing gratuitously throughout most of the day, evening, and even the night.

Although Mountain Bluebirds are known for their beautiful songs and calls, with males, their songs are more complex. This is probably to convince females that they're suitable mates. Also, males use songs to mark their territories.

Mountain Bluebirds can be quite territorial, and despite being a socially monogamous species, unpaired males often try to mate with nested females. In addition, males use territorial behaviors to prevent their mates from leaving with another bird.

Female Mountain Bluebird perched in the snow

Nesting and feeding

Mountain bluebirds are cavity nesters which tend to nest in pre-made cavities, i.e., tree hollows or, rarely, parts of abandoned buildings.

Males search for the nesting site, and once they've found a suitable hollow, they're often observed frantically calling out for a female to come and inspect it.

Once the female finalizes a nesting location, they set out to find materials to build their nest. These include things like animal hair, fur, or small leaves. The male stands guard to ward off any intruding male competitors or other birds and animals. Once the nest is ready, the two will mate, and the female will lay around 4 to 8 eggs.

Females only incubate the eggs while the male forages for food and feeds her. Some studies show that the female instructs the male as and when to do this.

Once the eggs hatch, the female signals to the male, who proceeds to bring her food so she can distribute it among the chicks. This process often takes a day or two to master - the male and female learn to work as a team. Then, males look after fledgling birds for a period while the female prepares for another brood.

A nesting Mountain Bluebird (female) with nesting materials in her beak

FAQs

Can female Mountain Bluebirds raise young alone?

Male and female Mountain bluebirds work closely together to find and refine their nesting cavity and then to feed and raise the young birds.

Even though the female handles incubation and brooding alone, the male remains present and feeds the female and chicks when they hatch.

Males also continue to look after fledglings while the female prepares for the next brood. So, it’d be extremely unlikely for a female to raise young alone unless the fledglings are highly developed.

What color are female Mountain Bluebirds?

Female Mountain Bluebirds have dull-brown plumage on the upper side and pale grey on the underside. They have some iridescent blue on their wings and tail, but nowhere near the extent of the male.

Do female Mountain Bluebirds call?

Female Mountain bluebirds are avid communicators and have various calls, most of which come into use throughout the breeding season. However, males possess more complex songs and sing freely throughout the breeding season.

Do female Mountain Bluebirds sing?

Female Mountain bluebirds do sing, but with less frequency, and in most cases, they sing solely for communication purposes. Males sing more gratuitously, i.e., not just when they need to for the sake of communication.