Most of the turkey buzzard we encountered in the valley in over 600 approaches to TGU were at 160 knots below 3,000 ft AGL. Yes, they can easily be avoided at that speed if you are scanning far enough ahead of the aircraft. If they get close enough to catch your attention without scanning farther out it is too late.
Our chief pilot grounded two 757's there probably because he was busy checking out another pilot and was distracted. After over 600 approaches there we got really good at missing multiple flocks and individual turkey buzzards. Once I was avoiding buzzards below 1,000 ft on approach and thought it would cause a go around but we were still able to land after clearing the birds. Maybe you can't avoid birds on approach with a large airliner but we had to to make a successful arrival and departure in and out of the valley.