The male robin who owns my garden replies: "BIRB birble birbly birble BIRB!" But he's only truly interested at the moment if you're a female robin or look likely to unearth worms or other delicacies. Male robins and all dunnocks need not apply.

Tetrapods are useless. Why bother to evolve a nervous system and then waste it on only two pairs of limbs?! ;-)