Throughout Vanity Fair, the narrator metaphorically compares a number of female characters, especially Becky and Amelia, to birds. In Chapter 12, he describes Becky as a hawk on the hunt and Amelia as some sort of young, nesting bird:
Snares or shot may take off the old birds foraging without – hawks may be abroad, from which they escape or by whom they suffer; but the young ones in the nest have a pretty comfortable unromantic sort of existence in the down and the straw, till it comes to their turn, too, to get on the wing. While Becky Sharp was on her own wing in the country, hopping on all sorts of twigs, and amid a multiplicity of traps, and pecking up her food quite harmless and successful, Amelia lay snug in her home at Russell Square;
Becky's characterization as a hawk makes sense considering her predatory behavior for much of the novel—she treats the world around her as a hunting ground, with everyone available as prey to help feed her ambition for wealth and grandeur. Amelia's description as a somewhat more harmless bird is also consistent with the narrator's treatment of Amelia as an essentially benevolent "creature" throughout the novel.
Much later in the novel, in Chapter 67, the narrator once again describes Amelia as a gentle bird—this time, one who has returned after a long flight to roost:
Emmy, whose shawl and bonnet were off in the passage in the hands of Miss Payne, now went to undo the clasp of William’s cloak, and – we will, if you please, go with George, and look after breakfast for the Colonel. The vessel is in port. He has got the prize he has been trying for all his life. The bird has come in at last. There it is with its head on his shoulder, billing and cooing close up to his heart, with soft outstretched fluttering wings. This is what he has asked for every day and hour for eighteen years.
There is a gendered component to these metaphorical descriptions—women have long been compared to birds in literature, in part because of the equation between the social expectation of a woman's delicate appearance and behavior and the fragile, delicate nature of many birds—but Thackeray's metaphor is not fully in line with this tradition. Becky's hawk-like qualities are brutal rather than delicate, and Amelia's warmth and gentleness is not a weakness but her primary strength. In the end, the comparison works because the flight paths and migration patterns of birds have a certain inevitability to them. Although the reader can only suspect it, the narrator has had a good grasp on the entire sweep of Vanity Fair from the very first page—and it was therefore only a matter of time before Amelia finally came home to roost beside Dobbin, the two morally redeemable characters nestled together at last.
