are blue bird eggs blue

Bird eggs range in colors and can be ornately maculated with spots, blotches and scrawls. They vary in shape and size, and they must be thick enough to withstand the weight of an incubating parent but thin enough to allow the embryo to break through and hatch. Other than heat and protection, all the resources needed for a chick to grow and mature are packaged up cleanly and tightly in the eggshell surrounding it. Learn to identify bird eggs and discover how egg color, size and incubation change from species to species.

A kiwi lays the largest egg in relation to its body size, but hummingbirds come in a close second when you add up the total volume of their two eggs laid in each clutch. Nests are built and eggs are incubated by the females. Like all hummingbirds, this species lays immaculate white eggs, but the eggs sit so deep in the cup-shaped nest that predators don’t see them unless they stand directly above the nest. Learn everything you need to know about hummingbird nests.

Yellow Warbler Eggs Clutch size: 4 to 5 eggs

Yellow warblers are popular targets of brood parasitic brown-headed cowbirds. The warbler eggs frequently do not hatch or the chicks may not survive to be fledged when the eggs of both species are present in the nest. Yellow warblers make alarm calls when cowbirds approach the nest, and the female may perch on the nest with her wings outstretched to ward off intruding birds. The warblers may bury a cowbird egg they discover in their nest by adding another layer of nest material on top of the invader’s egg. Learn how to attract nesting birds to birdhouses.

In order to comprehend why a large number of birds lay blue eggs, we must investigate the origin of the color as well as any potential evolutionary benefits.

There are only two pigments that give birdegg its color: biliverdin and protoporphyrin. Protoporphyrin is the pigment that gives brownish-red colors (like brown speckles). In the shell gland, biliverdin and protoporphyrin combine (or do not, in the case of all brown, all white, or all blue eggs) to produce the characteristic color and pattern (if any) of the bird’s eggs.

If you’ve never heard of biliverdin—as I hadn’t—you may be familiar with bilirubin, which is the pigment that jaundiced newborn humans should be concerned about. Bilirubin, which means “red bile” in Latin, is a yellowish substance that is created when red blood cells normally break down. Bilirubin is eventually eliminated from the body after being broken down by the liver.

Now, let’s go back to blue: the blue region of the light spectrum, which has wavelengths of about 450 nanometers, is what causes bilirubin to break down sufficiently to be expelled, thereby reducing the compound’s potentially dangerous concentrations.

I penned a piece for this column in November of last year regarding the rarity and difficulty of the color blue in nature. To my joy, it sparked a lot of discussion and inquiry, including a letter to the editor explaining why robins’ eggs are blue. This striking — and appropriate! — example of blue in nature struck me as a perfect subject for a springtime essay.

Baltimore Oriole Eggs Clutch size: 3 to 7 eggs

The egg of the pale gray-blue Baltimore oriole is marbled with sporadic, dispersed lines and squiggles. Occasionally, two birds that appear to be females will tend to a nest. However, one of them is typically a young male breeding for the first time, still sporting more cryptic plumage to help him avoid being noticed by more experienced and competitive males. Discover the eight distinct types of bird nests and how to identify them.

FAQ

What color are blue bird eggs?

Bluebirds usually lay blue eggs, but sometimes they are white. I continue to observe from a distance, or a walk by close enough to be able to see something that might be of concern. Bluebirds usually lay four to six eggs. They can range anywhere from off white to light blue to this bright turquoise.

Do blue birds lay blue eggs?

Bluebird eggs are blue, ranging from bright blue to almost white. Bluebirds usually lay four to five eggs. However, they don’t lay them all at once. Instead the female lays one egg each day until she has a full clutch.

Which birds egg will be in blue Colour?

Most of the thrushes in this area — the wood thrush, hermit thrush and veery — have blue eggs, as do Eastern bluebirds, European starlings, great blue herons and gray catbirds (although within all of these there can be a great deal of variation).

Why are blue eggs blue?

Blue egg laying breeds have a gene that applies the blue pigment to the eggshell as it is being formed around the egg. That is why blue eggs are blue all the way through, even to the interior of the eggshell. Green eggs are the result of a blue shelled egg being coated with a brown bloom coating.