Japanese quails are birds that spend most of their time on the ground. The eggs are laid on the ground as well, where they are easy prey for rodents, snakes and deer. Female quail choose where to lay their eggs in order to best camouflage them.
The eggs of the Japanese quail (Coturnix japonica) are fairly light in colour and have dark splotches. As the number and size of the darker spots is quite varied, there is not one ideal kind of place for the eggs. According to researchers from Scotland, the female birds “know” how their eggs look, and so they take this into account when choosing the colour of the ground. Just how the female quails do this is explained in the journal Current Biology. The birds make use of two kinds of camouflaging: background matching (or background coloration), and disruptive coloration. In background matching, an object has the same colour as its background. Disruptive coloration takes advantage of a pattern to make the shape of the object less distinct; the outlines disappear. This is how zebra camouflaging works.
The quail females seem to use both techniques. The investigators offered the quails four differently-coloured sandy surfaces. Quails that laid eggs with many, larger splotches chose a surface that resembled the splotches, thus making use of disruptive coloration. But quails laying eggs with few spots chose a surface that matched the background colour of the eggs, as this was the best form of camouflage in their case.
The researchers write that quails are not any smarter than other birds, but that when they choose the best method to protect their eggs and their progeny, the choices are quite specific.