American robin eggs, New Jersey, USA

© Mira/Alam

American robin eggs

These blue eggs belong to an American robin. The orange-breasted bird can be found across North America. Some migrate to Canada and Alaska, but many also remain in the United States and northern Mexico throughout the year. It is named after the European robin, but the two species are not closely related. Thanks to a process in the mother's blood, her eggs – which she can lay up to three times each year – are always coloured this lovely shade of blue. There’s even a name for this natural hue, 'robin egg blue'.