The speaker observes the bird and tries to establish contact with the bird by offering it food. The bird flies off. A few of the speaker's details describe the bird as a wild creature in nature, and more details present his behavior and his appearance in terms of human behavior.
Because the bird does not know the speaker is present, he behaves naturally, that is, his behavior is not affected by her presence. We see the bird's "wildness" or non-humanness in his biting the worm in half and eating it. "Raw" continues to emphasize his wildness. Ironically the word "raw" carries an implication of civilized values and practices ("raw" implicitly contrasts with cooked food). Why mention that the bird ate the worm raw? Would you expect the bird to cook the worm? In contrast, the fact that the bird "came" down the walk sounds civilized, socialized. Does this description sound like someone walking on a sidewalk?
The birds' drinking dew (note the alliteration) suggests a certain refinement, and "from a grass" makes the action resemble the human action of drinking from a glass. And the bird politely allows a beetle to pass.
In lines one and two, the description of the bird's looking around is factual description and suggests the bird's caution and fear, as well as a possible threat in nature. With lines three and four, the speaker describes the bird in terms of civilization, with "beads" and "velvet."
The idea of danger in nature is made explicit but remains a minor note in this stanza and in the poem. It occupies only half a line, "Like one in danger." "Cautious," the speaker offers the crumb. How is "cautious " meant? Does the speaker feel the need to be cautious? or does she offer the crumb cautiously? (One of the characteristics of Dickinson's poetry is a tendency to drop endings as well as connecting words and phrases; you have to decide whether she has dropped the -ly ending from "cautious.")
Her action causes the bird to fly off. Her description of his flight details his beauty and the grace of his flight, a description which takes six lines. Does the idea of danger or of the bird's beauty receive more emphasis, or are the danger and the beauty emphasized equally? Does it matter in this poem whether one receives more emphasis than the other, that is, would the different emphases affect the meaning of the poem?
I am suggesting that this poem reveals both the danger and the beauty of nature. Does the poem support this reading? What might Dickinson's purpose be in having the narrator see the bird in "civilized" terms? Is it a way of pushing away or of controlling the threat and terrors that are always present and may suddenly appear in nature?