Nests and Axes

Seeing this bird's nest, on a grey and dull day when there wasn't much else to blip, reminded me of one of the most interesting (and most speculative) parts of Robert Winston's Walking with Cavemen. He points out that Homo Ergaster, also known as Homo Erectus made very fine stone axes, but in the >1 million years that the species roamed the planet, the design and use of those axes never changed - in particular, they never thought of using them as spear tips. To try to explain how their making axes didn't involve creative thinking and the sort of practical reasoning which would lead inevitably to changes and improvements, he compared their axe-making to birds' nest-building.

But we now know that some corvids can not only use tools (we knew that some time ago) but also fashion new tools for specific purposes. This suggests that their intelligence has evolved beyond that of one of our most recent ancestor species. Fascinating.