or fresh nest entrances to luxuriant piles several centimeters deep. Often it will appear that
there are several nests in close proximity to each other, as in the photos to the right. Evidently these
are multiple entrances to a single nest. The ants will often have several active entrances, each
with a chaff mound, for each nest. The entrances typically seem to be within 15 or 20 feet of
each other. In a phenomenon that is similar to Lincecum's "ant rice", you
can see that the mounds in the photos at the right are surrounded by relatively lush vegetation,
especially after the winter rains. The effect is especially striking in relatively
barren areas such as the desert pavement in these photos.
nest after the winter rains. This one is surrounded by gold poppies. The photo on the
near right was taken during (one of the) dry seasons. The white object in the photo is a six
inch ruler. Note the lushness and depth of the midden, forming a mound around the nest. "Young"
nest entrances' midden piles usually start in a relatively restricted arc around the entrance,
forming a crescent which expands in depth and arc proscribed until the entrance is eventually
surrounded. 
Wind and rain storms clear out the middens periodically. The photographs on the lower right are
closeups of the chaff pile around a Messor pergandei nest entrance.
The small furry objects that are visible in the chaff pile are the coat from creosote seeds
(Larrea). Most of the long, curved objects are the seed pods of
gold poppy. As I recall, one of the entrances to the nest in the photo to the far right
is under/around the
rock in the upper left quadrant of the photograph.
and about on days of moderate temperature, I haven't had much luck predicting the activity on days
of more extreme conditions. Activity tends to be in the mornings and evenings (and nights?)
during the hottest time of the year. Messor pergandei is also
sometimes active on days that I assumed would be too cold - 55-60 degrees fahrenheit.
The picture on the far right shows a nest entrance during an active period. Note the lack of a large chaff pile, in spite of the number of ants and size of the nest entrance. The photo on the near right shows some Messor pergandei bringing seeds back into a nest entrance. The different size classes of ant is evident here.
Messor pergandei, next page