Interesting behaviour viewed while four of us were walking
along the beach, in stormy weather, on the peninsula north of
the town of Long Beach. Low tide, not many birds about but
there were a few flocks of sanderlings. I have read about the
following described behaviour, but this is the first time I have
actually seen it:

Driving is allowed on this stretch of beach, so although we saw
no cars there were tracks from about 5 different cars. One set
of knobby, but not particularly deep, tracks were interesting to
the birds. We would see, in the distance, long skinny masses
of sanderlings. As we came up to them you could see that the
masses were each one tire width wide. Solid sanderlings
covering each tire track, for a distance of 20 to 30 feet linearly
along each track. The birds were probing, of course, and the
track on the other side was always a little better than the track
that some were in, as there was a constant running back and
forth and trading places.

The best thing is that there were several sets of tracks, and it
was always only the two tracks from one vehicle that interested
the birds. We saw this going on at two different places on the
beach, both times the same two tracks. At other places along
the beach there were very few birds, and only a scattering of
probe holes. By the way, the tracks were not particularly close
to the water's edge, but back up where the sand just started to
get soft.

When we got too close the flocks would run out to the surf line,
and would probe a little out there, then run back to the tracks
as we passed.

We walked the same beach two more evenings, and never
saw a repeat of the tire track feeding frenzy. Just your
standard more or less random distribution of probing marks.

Wonder what they could see that one day that we couldn't?
Jerry Broadus
PLS 17660