Science has recently become aware that pigeons navigate not only by magnetic means but also by landmarks. The birds have been clearly tracked following roadways and turning at particular intersections. But pigeon keepers in my acquaintance have been aware of this behavior for some time. One who flies birds in New Mexico has observed:

Here in the desert Southwest, racing homers will go around any of the "Sky Islands" they encounter, always. Landmarks like I-10 and I-25 are used here as well; birds I trained west or north virtually followed the interstates as far as they could before breaking off at key points.

Underrated birds, pigeons.