Listening to these mockingbirds improv reminds me of a factoid I read today in Daniel Tammet’s Embracing the Wide Sky that in order for male songbirds to sing some of the incredibly complex songs which change constantly, up to one per cent of the neurons in their song center are replaced by new neurons every single day, which adds up pretty quickly. That’s what those mockingbird brains are doing, rebuilding themselves continuously. Not adding brain cells to what is there already, but replacing them. It’s as if in order to speak we had to replace 100% of the neurons in our language center every 100 days. That is, all the grammar we’ve hardwired into our brain is replaced by entirely new brain cells with all new intricately laced connections between them four times a year. It’s not quite that simple (some of the neurons in the mockingbird’s song center will be replaced more often than others and others are more permanent), but still, our grammar and vocabulary would completely and fundamentally change over a period of a hundred days. Not all at once, but a little everyday so that you’d be speaking a completely different language in April from what you were speaking on January 1. I’m writing this in English now and a hundred days from now I’d be writing this in Armenian, and next year in Sioux. Plus I’d wake you up at five in the morning screaming outside your window.