Learn how to identify bird eggs by color and size. One of the most interesting bird egg facts that despite the broad variety ...

Q. I saw a photo of different kinds of bird eggs and noted not only the obvious, that smaller birds lay smaller eggs, but also that some bird eggs are elongate whereas others are more rounded.

2010). These and other cuckoo hosts appear to have evolved a simple rule of thumb to direct their behavior: "eject the egg unlike your own". But how does a bird know what its own eggs look like?