they say birds are lactose intolerant, but i've given my parrots lots of cheese and yoghurt over the past 24 years, and they've never suffered any ill effects. in fact, birds, especially egg layers are often times defficient in calcium and vitamin d (d3 actually), so giving them dairy is a good thing for them.
My cockatoo loves milk, buttermilk, cheese, yogurt, & ice cream. Don't try to drink milk without offering some to him. Your ears will suffer for it. My African grey would have liked to have lived on only cheese.
Ranch type vegetable dip:
In a blender, 1 cup mayo, 1 cup buttermilk, minced garlic to taste, S&P, chopped parsley, 5 saltine or townhouse crackers. Blend until smooth and refrigerate. It thickens up.
This is so great for dipping broccoli, cauliflower, celery, carrots, radishes and more.