A confusing mass of figures, they looked like tangled bird tracks.

Verin scratched a fourth line, turning the bird track to a lopsided star.

"I never saw bird tracks like these, Mr. Smith," he muttered.

A third line made a bird track.

Among the most difficult are the carvings that were identified as bird tracks; they may have originally been abstract designs or arrowheads.

She noticed many bird tracks in the sand.

In the sand, some of the three-toed bird tracks were small, and so faint they could hardly be seen.

The faint feel of bird tracks left from a sparrow crossing the newly poured cement sometime in the far past.

Still interpreting them as bird tracks, he classified the trackmakers based on whether their toes were thick or narrow.

The result looked like flyspecks and bird tracks around the photo, but the computer assured them it was the proper translation.