Did some quick maths, it’s roughly 10% for the bird (2W, approx. 4g/day of fat, over 10 days) so not negligible but doesn’t change the full story.
And you could argue the plane also has a baseline metabolism ;)
And you could argue the plane also has a baseline metabolism ;)
You could not scale down a plane to the size of a bird and match their efficiency. On the other hand you also couldn’t scale a bird to the size of a plane so I guess we can call it even!