Young females can be mis-sexed as males by the pelvic sexing! It depends on how old the one you think is a male. You may have both females! Like Monica says, males can do it too, but it's more of the female's thing to do. All the ones I've raised before, only the females does it. How old is your pair? During any time your unsure if they're sick or not, you should always bring them into the vet as we can only speculate. With birds, you can not just say oh he looks better, you need to be SURE he is better!