Interesting article about Shearwaters.shearwater.jpg
It seems that female Shearwaters vary the amount of food they bring to their young, depending upon their cries, whereas the male Shearwaters always bring exactly the same amount of food. So, I guess Kevin is not just being cheap by only bringing Harry 4 ounces of formula regardless of how hungry he is. Kevin just can't tell how hungry he is - it is inherent!