"The Birds" is written in third-person limited, closely following Nat's perspective. Du Maurier uses detailed, vivid imagery to describe the landscape and the birds in particular. Her descriptions are often poetic and repetitive:
The restless urge of autumn, unsatisfying, sad, had put a spell upon them, and they must flock, and wheel, and cry; they must spill themselves of motion before winter came.
In this sentence, du Maurier layers similar adjectives to compound their effect ("restless," "unsatisfying," "sad") and uses figurative, ornate phrasing ("spill themselves of motion," as if motion were a liquid). However, the narration occasionally blends with Nat's thoughts, conveying the immediacy of a situation through plain language and brief, straightforward sentences, even sentence fragments. For example:
Then he saw them. The gulls. Out there, riding the seas.
At certain points, du Maurier even picks up Nat's dialect, which is somewhat distinguished by both class and region. Rather than write out "southwesterly," she describes "the storm and bluster of a sou'westerly gale." Towards the end of the story, Nat imagines putting away supplies and getting the cottage "ship-shape, handy-like." Both of these expressions also indicate Nat's familiarity with the sea and with nature generally, more intimate than a Londoner's would be, but also more foolhardy, since this new natural disaster is against all expectation and precedent.