The first step to identifying butterfly eggs is knowing where to look. Butterflies require specific host plants to lay their eggs on so becoming familiar with these plants and including them in your garden will increase your chances of finding eggs.
If you are able to watch the female lay her eggs you’ll have a better idea of where to look on the plant. Even so, the eggs are tiny – about the size of a pinhead! So look closely, usually on the bottom of a leaf, but occasionally on the top of a leaf or a stem. Good luck!