The European robin is a native to the UK and a common feature of the British garden brid table and the Christmas card. Their eggs are commonly found in nests across the country. However, what many who welcome this red-breasted bird don't realise is that the American's have robins in their back gardens that is unrealted to the original, European robin. This means there not one kind or colour of robin egg, but two.
European v. American robin eggs
The eggs of the European robin are white or pale blue with a multitude of reddish-brown spots. The American robin, on the other hand, lays eggs which are blue or blue-green with no markings. These eggs are so common and the colour so distinct, that the shade is commonly called "robin's egg blue." While the eggs of the European robin look more like speckled stones, the eggs of the American robin have been an inspiration for shades of various blue paints and dyes.
Other blue eggs
The American robin is not the only bird that lays blue eggs. Many birds, including birds that often share the American and European robin's habitat, lay eggs of a very similar shade. Starling eggs are often confused with robin eggs, as they are a very similar size and shade. However, robin eggs are slightly lighter than those of starlings. Bluebird eggs are also sometimes confused with robin eggs, but robin eggs are a rich shade of cyan or sky blue while bluebird eggs are a light blue.
Official colour definition
The American robin egg shade has become an official colour. Robin's egg blue is officially defined by the Inter-Society Colour Council-National Bureau of Standards (ISCC-NBS) as one of two colours. The first is #8da399 and the second is #66ada4. These colours translate into RGB colours 102, 173, 164 and 141, 163, 153 respectively (RGB colours are colours described in proportions of red, green and blue). The equivalent CMYK colours (colours described in terms of cyan, magenta, yellow and black), are 0.41, 0.00, 0.05, 0.32 and 0.13, 0.00, 0.06, 0.36.
Common colour definition
Even though robin's egg blue is officially defined, the official colour does not approximate the actual colour of a robin's egg. Therefore, the more common definition of robin's egg blue is as pure cyan, a colour equal parts blue and green. Robin's egg blue is also the name of a Crayola crayon colour first introduced in 1993. It also is a vivid blue-green colour reminiscent of the shell of its namesake.