#TBT A Blue Like No Other: Why are robin eggs blue?

A Blue Like No Other by Jamie MacDonald

A Blue Like No Other by Jamie MacDonald

Here’s a Throwback Thursday from April of 2009 in honor of Spring, which I hear is still happening. The resource on the initial post is no longer online, so I dug up this post from The Spruce explaining why robin eggs are blue:

The color of an eggshell is determined by pigments deposited as the shell is formed in the shell gland. The shell gland is the avian equivalent of a mammal’s uterus and is near the end of the oviduct, just before the cloaca. The shell is formed just before the egg is laid.

The bile pigment biliverdin is responsible for blue tones in bird eggs. Depending on the concentration of the pigment, the coloration can range from bright, bold blue or blue-green to pale ice blue and every shade in between. Smaller eggs and those laid first in a brood are usually more intensely colored than larger eggs or those laid later in the nesting cycle.

In addition to coloring eggshells, biliverdin is also responsible for blue tones in moth and butterfly wings, and is the same pigment that makes bruises turn bluish-green.

Read on for more and see a bunch more awesome shots in Jamie’s Nature photo album.

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Spoon Flower

Spoon flower, photo by Bailwick Studios

The photographer writes that this flower might also be called a spooned daisy, African daisy, or a caped daisy.

View the photo background bigtacular and see more in Bailwick Studious slideshow.

More flowers on Michigan in Pictures!

Blue Monday

blue, photo by Curt Saunier

View Curt’s photo bigger and see more in his Flowers slideshow.

Why is Ice Blue or Green?

The Blue Ice

The Blue Ice, photo by Charles Bonham

The Causes of Color answers the question: What causes the blue color that sometimes appears in snow and ice?

As with water, this color is caused by the absorption of both red and yellow light (leaving light at the blue end of the visible light spectrum). The absorption spectrum of ice is similar to that of water, except that hydrogen bonding causes all peaks to shift to lower energy – making the color greener. This effect is augmented by scattering within snow, which causes the light to travel an indirect path, providing more opportunity for absorption. From the surface, snow and ice present a uniformly white face. This is because almost all of the visible light striking the snow or ice surface is reflected back, without any preference for a single color within the visible spectrum.

The situation is different for light that is not reflected, but penetrates or is transmitted into the snow. As this light travels into the snow or ice, the ice grains scatter a large amount of light. If the light is to travel over any distance it must survive many such scattering events. In other words, it must keep scattering and not be absorbed. We usually see the light coming back from the near surface layers (less than 1 cm) after it has been scattered or bounced off other snow grains only a few times, and it still appears white.

In simplest of terms, think of the ice or snow layer as a filter. If it is only a centimeter thick, all the light makes it through; if it is a meter thick, mostly blue light makes it through. This is similar to the way coffee often appears light when poured, but much darker when it is in a cup.

Click through for lots more about light & color!

Charles took this photo last March off Gills Pier on the Leelanau Peninsula when there was a whole lot more ice than there is this winter. View it background bigilicious and see more in his Leelanau Peninsula slideshow.

More winter wallpaper and more amazing ice on Michigan in Pictures.

Blue Anticipation

Blue Anticipation

Blue Anticipation, photo by Elizabeth Glass

I dug way back through the over 13,000 winter photos in the Absolute Michigan pool on Flickr for today’s photo.

Liz Glass took it at the Straits of Mackinac in 2011. She says that the color is real and recommends you check it out bigger to see the details on Fluidr. It’s also a cool way to look at her Ice set (or view the slideshow on Flickr).

More ice on Michigan in Pictures.