Bluebirds, known for their vibrant colors, captivate observers in North America. These small thrushes are often seen perched in open areas, their striking adult plumage a familiar sight. The journey from a tiny egg to a fully colored adult involves distinct stages, each with its own unique appearance. Understanding these developmental phases offers a deeper appreciation for their life cycle.
Appearance of Nestlings
Upon hatching, nestlings are altricial, completely dependent on their parents. They emerge from their eggs blind and largely featherless, weighing around 2.4 grams (0.08 ounces). Their skin is a delicate coral-pink, with sparse, gray downy tufts along their head, spine, and wings. Within the first couple of days, their skin begins to darken to a bluish-black as tiny pin feathers start forming beneath the surface.
By days five to six, the nestlings’ eyes begin to open as slits. Over the next few days, the contour feathers continue to emerge, gradually replacing the initial down. By day 12, nestlings are almost completely feathered, though some bare areas may be visible on their belly and under their wings. Their legs and feet are well-developed, allowing them to stand, stretch their wings, and preen within the nest.
Appearance of Fledglings
Once bluebirds leave the nest, between 16 and 22 days after hatching, they enter the fledgling stage. Their plumage differs notably from nestlings and adult bluebirds. Fledglings are generally grayish, lacking the intense blue of mature birds. A distinguishing characteristic of young bluebirds is their speckled breast, typical for members of the thrush family.
While predominantly gray, fledglings show variable amounts of blue on their wings and tail, though it is a duller shade compared to adults. Their wings appear short and rounded, still growing, and their tails are often shorter. They have a less refined appearance than adult bluebirds. Although they have left the nest, fledglings fly short distances initially and remain dependent on their parents for food for several weeks.
Key Distinguishing Features
Identifying a young bluebird involves recognizing characteristics that set them apart from adults and other young birds. The most prominent feature of a young bluebird, particularly a fledgling, is its speckled breast. This spotting is temporary plumage, a hallmark of their juvenile stage, disappearing as they mature.
Another factor is the intensity of their blue coloration. Unlike the vibrant blue of adult male bluebirds, young bluebirds have duller blue on their wings and tail, or sometimes only hints of blue. Their backs are often grayish, sometimes with pale spots, contrasting with the solid blue of adult males. While male fledglings may show more blue earlier, the muted tones and speckled chest are reliable indicators of a young bluebird.