How can birds still fly if they have to constantly eat to have enough energy to fly? Doesn’t eating make them so heavy that they need even more energy to keep flying?

Question

When I watch the birds at the feeding station in my garden, I notice that individual birds often eat a lot at once. Doesn’t all that food make them so heavy that they need more energy/food to fly than they can carry in flight?

In: Biology

Answer 1

Their bones are structurally different from ours. They have hollow bones, which helps them twofold; to reduce overall weight and to store oxygen in their bones. And feathers make a bird (or animal in general) seem bigger than they are, you look at a bird and deduce from their size that they seem heavy while even the biggest owls only weigh around 2-5 kg.

Birds eat as much relative to their stomach volume allows, therefore the common mistake of giving breadcrumbs is actually bad for avian animals. They have to be really efficient with their food intake, and bread is neither good nor bad for you. As it lacks essential fatty acids and many amino acids, this is equivalent to them eating donuts all day (rich in calories, low in essiential building blocks of life). Fine on the short term, bad for longevity. They have to carefully find their correct food supply, or they will not be able to fly (bread lacking the fat content to ensure the feathers with enough oil for aviation) and other complications.