Not sure about density, but birds that aren’t adapted to water don’t produce the oil and don’t have the interlocking feathers to trap air and make them float very well. And you’ll find plenty of rescue videos of birds struggling to get out of water they’ve accidentally ended up in, e.g. owls, pigeons.
Is there a bird too dense to just float?
Like I think penguins even float don’t they?
Maybe dodos
Pretty sure dodos don’t float any more :)
Not sure about density, but birds that aren’t adapted to water don’t produce the oil and don’t have the interlocking feathers to trap air and make them float very well. And you’ll find plenty of rescue videos of birds struggling to get out of water they’ve accidentally ended up in, e.g. owls, pigeons.