I think polymorphism is better? Depends on compiler optimizations. If that's a bad optimizer, it will translate the switch with a bunch of if/then/else, otherwise it will be translated as a jumptable (Virtual classes have kinda a jumptable, the vtable)
> I admit typing the switch is a lot faster than doing polymorphism
Right now, yes. But if tomorrow you wand to add a couple of more birds, say thrush and wren, (or for that matter some more operations) you might find that a polymorphic hierarchy of birds is easier to maintain.
Either may be better - you need to take a decision based on your expectation of how your program might evolve.