Both zoom and prime lenses are used; zoom lenses (generally in the 70–200, 75–300, 100–400 or 200-400 range) allow a greater range of framing; primes are faster, cheaper, lighter, and optically superior, but are more restricted in framing.
Zoom lenses (usually within the 70–200, 75–300, 100–400 or 200-400 range) provide a wider variety of framing options; primes are faster, cheaper, lighter, and optically superior but have fewer framing restrictions.