Occasionally as she watched, she saw a slight movement behind this or that butt--no more--and the only evidence of human beings, beside the beaters, lay in the faint wreath of all but invisible smoke that followed the reports, coming now quicker and quicker, as the grouse took alarm.

Once with a noise like a badly ignited rocket, there burst over the curve before her a flying brown thing, that, screaming with terrified exultation, whirred within twenty yards of her head and vanished into silence.

(One cocked ear of the mare bent back to see if the rocket were returning or not.) Jenny's meditations became more philosophical than ever as she looked.
She found herself wondering how much free choice the grouse--if they were capable themselves of philosophizing--would imagine themselves to possess in the face of this noisy but insidious death.

She reminded herself that every shred of instinct and experience that each furious little head contained bade the owner of it to fly as fast and straight as possible, in squawking company with as many friends as possible, away from those horrible personages in green and silver with the agitating red flags, and up that quiet slope which, at the worst, only emitted sudden noises.

A reflective grouse would perhaps (and two out of three did) consider that he could fly faster and be sooner hidden from the green men with red flags, if he slid crosswise down the valleys on either side.