Spanish is the same as French then, so it is natural he'd say she.No. In English there´s no default and usually an animal of unknown gender is referred to as it. Eg. ¨The cat plays with it´s ball in the garden.¨
In Spain, Every animal already has a gender ¨assigned¨ because the actual word is feminine or masculine.
For example, Elefante (elephant) is masculine. Jirafa (Giraffe) is feminine.
Pigeon is Paloma, and Dove is Tortola - both are feminine. So when talking about the animal without knowing it´s gender it would be reffered to by ¨it¨ but here we have masculine or feminine ¨it¨ - ¨El¨ male or ¨Ella¨ female. There is no masculine/feminine neutral ¨it¨ word here.
So linguistics made him call Pepper ¨She¨.
BTW, is there a way to visually sex doves? The parents look the same ...
As for English, I've often heard people say she of a baby for example, although there was nothing to indicate it was a girl. And since baby is a masculine word in French, I noticed.