The chapter opens with a description of the poultry farm at The Slopes where Tess is going to work.
The poultry house is an old cottage where tenant farmers (folks who paid the lord of the manor yearly rent for the privilege of eking out a living by farming) used to live. But now it's all overrun with chickens.
Tess begins to tidy the place up, when a maid comes in and tells her that Mrs. D'Urberville "wants the fowls as usual" (9.4).
Apparently, Mrs. D'Urberville is a blind old lady, and likes to inspect the chickens individually each day by feeling them with her hands.
So Tess and the maid bring the chickens and roosters to her, one at a time, and allow her to inspect them.
Mrs. D'Urberville then "inspects" Tess herself—and unexpectedly asks if she can whistle.
Whistling wasn't considered all that "ladylike" at this point in time, but Tess admits that she knows how.
Mrs. D'Urberville wants Tess to whistle tunes to her pet finches. Because she can't see them, she likes to hear them tweet, and they learn tunes if someone's there to whistle to them.
Tess goes back to the poultry farm and practices whistling alone.
She hasn't tried in so long, she's having a hard time remembering.
Suddenly she realizes she's not alone—Alec is watching her pucker up her lips through the fence.
Alec offers to show her how it's done, and after a few tries she gets it again.
So Tess starts whistling to the birds every day, and Alec continues to hang out near her and flirt with her, until she gradually gets used to his company. Although she still doesn't love him, she doesn't mind him as much.
One day, as she's whistling to the finches in Mrs. D'Urberville's room, she notices Alec's feet sticking out at the bottom of Mrs. D'Urberville's canopied four-poster bed.
Tess starts checking the bed every morning before starting her whistling routine, but apparently Alec has given up the idea of "ambush[ing]" her in that way.