This competition asked you to design a secret egg hidden somewhere in nature, and your entries went far beyond the obvious nests and burrows. Eggs arrived disguised as pine cones, floating on leaf boats, perched on volcano ledges, tucked into cloud cover and even masquerading as chocolate Easter eggs to fool foxes. Thank you to every reader who took up the challenge and thought like a parent bird, fish, reptile or imaginary creature trying to keep their precious egg safe.

We were swept away by the response to this competition. Letters arrived from rivers across the world – the Thames, the Mississippi and many more unnamed waterways – each one brimming with personality, passion and a genuine love of the natural world. You gave your rivers voices that were worried, hop...

Somewhere beneath a grassy field right now, a tiny insect is building an underground loudspeaker. Male mole crickets engineer horn-shaped burrows that amplify their calls hundreds of metres into the night air – and your child can recreate the same science at home using nothing but cardboard and a phone. This hands-on experiment explores sound, shape and natural engineering in a way that is genuinely surprising. No screens, no special equipment, just a brilliant idea borrowed from nature.