David Haye has probably had too many blows to his head 😵💫.
In his defence, there is a general feeling that beauty and brains don't go together. The archetypal brainy person is plain, dowdy and wears glasses. This may not sit well with lots of women, but it doesn't bother me.
Exceptions to this thinking, in the media, are Rachel Riley, Carol Vorderman and Vanessa Feltz (I can't think of anyone else, it's very late.)
If you watch University Challenge, it's rare to see a beautiful woman, but they are very clever, that may just mean that the beautiful, clever ones don't want to take part.
With this in mind, I would take Haye's comment to mean his girlfriend isn't only beautiful, but clever too.
Ugly bird isn't a term I would ever use, but neither would I call a man a minger, pug ugly or any other derogatory term relating to looks. Beauty and attractiveness to me come from a happy, smiley, kind person. A pretty woman or handsome man can come across as very unattractive if they are nasty, cruel, or rude in their manner. Likewise, a plain looking person, male or female, can be very attractive if they have a happy, cheerful, friendly and kind personality.
I haven't watched the programme in question, but Haye probably thought his comment would raise a laugh with his camp mates, he didn't know that he would be scrutinised by Gransnetters, a force to be reckoned with 😆.