Bo was looking up and listening.
"There he is!" cried Bo, as the hound bayed ringingly, closer to them this time, and she spurred away.
Helen's horse followed without urging.

He was excited.

His ears were up.
Something was in the wind.

Helen had never ridden along this broken end of the park, and Bo was not easy to keep up with.

She led across bogs, brooks, swales, rocky little ridges, through stretches of timber and groves of aspen so thick Helen could scarcely squeeze through.