Birds have always amazed me, but there's something about what happens now in spring that, for me, defies belief. Prompted by the gathering day-length and guided by their complex internal genetic coding, they set about creating artistic masterpieces - nests.

This week, my Robins, Dunnocks and Blackbirds have all been on the intense hunt for nesting materials, but I was thrilled to see that my Song Thrushes are too.

All I have for you is a grabbed photo through the lounge window but I hope you can make out the beakful of dried grasses.

She is building in a small Bay tree, a plant I don't normally rave about from a wildlife point of view, and while its evergreen cover is providing her with some protection, I do think she is very vulnerable to the squirrels.

Nevertheless, just to see her in action as she wanders the garden fills me with such wonder. As she searches, you get the sense that she is absolutely clear what piece of bark or twig or rootlet she needs next. Many times, she will pick something up, maybe shake it a bit, then drop it as clearly substandard.

But then she spots what she needs. "Ah, yes, this is THE crinkled brown leaf I've been looking for!" It's as if there is no doubt. Up she flies to add it to her creation, something she may never have built before and yet which must provide a nursery of strength and durability and perfect proportions.

Nature, eh? Astonishing!

If you want to drop by my RSPB wildlife gardening blog, it is updated every Friday, and I'd love to see you there - www.rspb.org.uk/community/blogs/hfw