Two different types of binoculars. Porro prism , eye piece is not inline with the exit lenses. More affordable, but more bulky. Harder to make dust and waterproof.
Roof prism.. eye piece in line with exit lenses. More streamlined, easier to make dust and waterproof. More expensive.
I prefer roof prism because I'm carrying them around a lot. And a smaller package helps. I'd stick with a 7x40, to 10x40. Stay with a "40" or little larger. Explanation below
The " 7" is the magnification. The higher, the closer the object will appear. However the higher it is the harder to hold steady. The "40" is the size of the lens in MM. The bigger the lenses, the wider the field of view, making it easier to find the object. Also the wider the lenses, the more light they let in. Makes a big difference in the early morning and evening.
You can get a very nice pair of vortex, Nixon, or Leopold for $250 or less