Excerpt:

Red-tailed Hawks are regular visitors to the Nature Reserve on the former airfield at Alameda Point. The Northern Harrier, another type of hawk, also visits the reserve, but are fewer in number and harder to spot.

Red tails and harriers both like the wide open space and grassland where they hunt for prey, but they differ in their abilities to hunt. The red tails rely on keen vision and are able to hunt from great heights and distance. Harriers, on the other hand, rely on hearing in the same way that an owl does. The harrier’s face has characteristics similar to an owl that allows it to capture sounds and direct them to their ears. They have the ability to hear the sounds of small animals moving in the grass. They fly close to ground, sometimes within 10 feet, methodically moving about listening for movement.