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

So, there IS a degree of diminishing returns, where extra energy is just mostly lost into moving that extra mass, but most birds are nowhere near that level. It’s like filling the fuel tank of a car, its not enough extra mass to make much difference.

Plus, they never really know when their next meal will be, so generally it’s always a good survival trait to fill up whenever you can.