There are a couple of spots where the speaker of "A Bird came down the Walk" voices conflicting, or ambivalent, feelings regarding nature, primarily seen through her focus of the bird noted in the title.
In the first stanza, the speaker is focused on watching a particular bird who does not care to notice her. This is an oddity in nature as most birds are skittish around humans unless they have been trained in their interactions with them. However, this bird allows the speaker to both get close enough for her to inspect his meal yet doesn't care enough to allow her to interfere with his small hunt. Thus, she watches him eat a worm, biting it in half, swallowing it "raw." The connotation of "raw" is particularly interesting. After all, how else would a bird eat a worm? Yet this word choice conveys a barbaric and inhumane nature of the bird that is conflicting with typically peaceful images of birds which readers might conjure.
The speaker then attempts her own interaction with the bird. She offers him a "crumb," a little meal which he doesn't have to hunt for. This is also a food that is likely man-made, such as a crumb of bread which the speaker has brought with her. The bird not only rejects her human offering but flies away from her presence.
The speaker is distinctly separate from the realm of the bird, though she desires to be more involved with him; this leads to ambivalent feelings.