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

Note that birds spend a lot of time not flying. They can just have a nap if they want to. Documentaries and factoids seem to imply that birds like hummingbirds are incapable of rest, and must eat 24/7 to avoid starvation, when in reality, they only need to do that to maintain their energy consumption while flying.

There are many different “styles” of flight among birds as well. These allow birds to avoid spendig extra energy. Large seabirds like the Albatross have evolved to be able to
fly with very little effort, and can stay in the air without spending much energy for a very long time. This comes at the cost of havin a difficulty time taking off on short notice. Parrots meanwhile, are optimized for dense forests. Although they are inneficient flyers, they can maneuver quite well, take off with little effort, and can use their beak and claws to climb trees. They perfer to fly in short bursts rather than going long distances.