The party was primarily for Lady Ethelrida's birthday, and the shoot merely an accessory.
Zara walked by the Crow, who was not shooting at all.

She was wearied with Lord Elterton; wearied with every one.

The Crow was sententious and amused her, and did not expect her to talk.
"You have never seen your husband shoot yet, I expect, Lady Tancred, have you ?" he asked her; and when she said, "No," he went on, "Because you must watch him.

He is a very fine shot." She did not know anything about shooting, only that Tristram looked particularly attractive in his shooting clothes, and that English sportsmen were natural, unceremonious creatures, whom she was beginning to like very much.

She wished she could open her heart to this quaint, kind old man, and ask him to explain things to her; but she could not, and presently they got to a safe place and watched.
Tristram happened to be fairly near them; and, yes, he was a good shot--she could see that.