A blackbird has chosen an odd place to nest: a roundabout where five roads meet a hot, pale highway. The speaker watches her with gentle amusement and real curiosity. The "caravan park" is a playful image, treating her nest like a temporary holiday stop in the middle of all that traffic.
The central question is why she would pick "the straight & narrow" over a hedge, which the speaker imagines as a "Medieval maze of streets." The pun on the straight and narrow hints at the human world of rules and roads, set against the tangled, older world of hedgerows. The title, which mentions St. Kevin and a blackbird, suggests a link to a saint-and-bird story, though the poem never spells it out. At the end the bird simply watches the blinking lights and tilts her head toward traffic she can't see. The mood is quiet, wry and observant, with a little wonder at how living things adapt to our noisy landscapes.