Hialmar asks hesitantly if anyone has found his hat on the stairs; apparently he lost it the night before. Gina chastises him and enters the kitchen to fetch a breakfast tray for him. While she is out, Hialmar hastily examines the torn letter from yesterday. He refuses food upon her return. When Hedvig enters the studio again, he rejects her anew and storms into the next room and Gina follows. Terrified, Hedvig takes the pistol from the shelf and creeps into the garret.
Hialmar and Gina argue over packing. Utterly exhausted, Hialmar slumps onto the sofa and unthinkingly begins to eat his breakfast. In face of the endless preparations involved in the prospective move, Gina suggests that he stay in the sitting room for a few days. Hialmar ultimately agrees. He also glues Werle's letter back together. After all, it is for his father, and not he, to decline Werle's offer.
Gregers enters and Hialmar quickly rises. Gregers attempts to strengthen Hialmar's resolve to adhere to the ideal. Hialmar has his invention before him and reveals that it invention was Relling's idea. It brought him happiness only in inspiring Hedvig's faith. Now he is convinced Hedvig has been false with him. She has never truly loved him and would readily run off with the Werles if promised their fortune. Hedvig "[blots] the sunlight" from his life.
Suddenly a shot rings out from the garret. Gregers is triumphant: he announces that Hedvig has gotten her grandfather to sacrifice her precious duck to prove her love for her father. Suddenly Ekdal appears in full uniform. The group realizes that he has not shot the duck—it would appear Hedvig has done it herself.
Hialmar tears open the garret door. The group follows, only to discover Hedwig lying on the floor. The men lay her on the couch as Gina calls for Relling. Ekdal murmurs quietly that the woods have avenged themselves. Upon examining her, Relling declares the child dead; the bullet has pierced her chest and caused an internal hemorrhage. "In the depths of the sea" murmurs Gregers. Hialmar screams remorsefully that he hunted her from him like an animal. Molvik makes a drunken benediction. Gina asks that they take her to her room. She and Hialmar must help each other mourn. Now Hedvig belongs to both of them.
Once the members of the household have left, Relling informs Gregers that Hedvig certainly killed herself. Gregers consoles himself that Hedvig did not die in vain but set free "what is noble" in her father. Relling retorts that this nobility will not last—within a year Hedvig will be but a "pretty theme for declamation." Moreover Gregers has little reason to concern himself with the Ekdals further: people do fine if others do not pester them with talk of ideals. If Relling is right, Gregers declares, life is not worth living. Walking off, he announces that he is glad of his destiny—to be the thirteenth at the table. "The devil it is" answers Relling.
The first of these final scenes stage Hialmar's comic return to the household. Once again, domesticity comes to deflate Hialmar's melodramatic exhortations. Despite his declarations that he cannot live among traitors and appeals to the ideal, Hialmar will settle into his domestic routine in the studio, accepting Gina's care and absently taking his breakfast as always. As Hialmar protests defensively to Gregers, "the body sometimes makes its claims felt too." Note the petty objects that pepper the scene of Hialmar's return: the missing hat, the bread, butter, and coffee on the breakfast tray, and the portmanteau. These objects bring Hialmar back into domestic routing. The fiery hero refuses to admit his capitulation. The welfare of Old Ekdal serves as a pretext as a return, his sighs of "poor father" allowing him even to repair Werle's letter. It is all too obvious that Hialmar cannot bring himself to leave his home, the private circle within which he figures as a "shining light" among men.
Hialmar's grudging, shamefaced return to the household heightens the dramatic irony of the act's climax—Hedvig's suicide. Hedvig kills herself in believing that father will never return. The final dialogue between Gregers and Hialmar, in which the former denounces Hedvig was a traitor, subtends this structure of irony as well. This climatic death also involves a delicate structure of suspense. Hialmar's repudiation of Hedvig sends her into the attic with the gun. This component of the action is then momentarily held in expectancy as Hialmar grudgingly returns home. Hialmar then denounces Hedvig to Gregers as a traitor. Hedvig's suicide violently intrudes into the playing space anew with the gunshot that interrupts their dialogue.
As noted above, Hedvig's death takes the metaphoric substitution of Hedvig and the wild duck to a lethal conclusion. Hedvig enters the garret to kill the duck and destroys herself instead. As Gregers notes, she has now truly retired to the depths of the sea. This death is the logical conclusion to Hedvig's martyrdom as the play's victimized innocent, and she literally appears the bloodless victim. Hedvig finally becomes the wild duck in substituting for her as an object of sacrifice. The chilling or even violent quality of the cast's pity for the martyred Hedvig becomes clear in Gina and Hialmar's reconciliation over her corpse. Though they could not mutually claim her in life, she is certainly theirs in death.
Finally the play ends with a dialogue between the play's two "spiritual doctors"—Gregers and Relling. This dialogue offers a closing commentary on Hedvig's demise. True to form, Gregers attempts to find redemption in Hedvig's demise and specifically the redemption of his idol, Hialmar. Hedvig's death would bring out what is noble in his friend. The sardonic Relling knows that Hedvig will become but another theme for Hialmar's endless declamations before the year is out. This final observation leaves Gregers thoroughly disillusioned. Thus, he stages the exit from the world in which he has little place, an exit he enigmatically alludes to early in the play in his conversations with his father.