Puppy Confused by His Own Reflection

We have a cock pheasant who comes into our garden and attacks his reflection in a mirror I have propped against the shed. I've had to turn the mirror round as I'm afraid that the pheasant will break a beak or something!

I've had lots of cats, dogs and pets from childhood on up. Some were intrigued with their reflection and others couldn't care less. I wonder why it is that some cats/dogs seem to think the reflection is another animal, some seem to recognize it as themselves, and others don't even seem to see the reflection at all.

i've always tried to get my cat to take notice of this

but she seems intrinsically uninterested in everything but pooping