North Island robins are feisty little chaps, fiercely territorial and willing to butt heads with bigger rivals. Not only this but they can 'calculate' large quantities. Now, most animals can understand numbers to four or thereabouts (two is less than three, for example) but these robins can understand up to sixty or so. So don't be thinking that you can grab a few mealworms from a robin without him noticing: he'll peck your toes until you holler!

More information:

natureworldnews.com/birds-count