I mentioned the Yellow-rump Warblers sometimes pecking at ants. Actually ants have been putting on a show nearly as interesting as the birds'.
Sunday afternoon Fred called me to come look at the Pavement Ants I told you about a few Newsletters back, back when they were being eaten by yellowjackets. The ants are members of the Myrmicinae, probably TETRAMORIUM CAESPITUM.
This time the ants were forming an enormous column averaging about ten ants wide and marching along the sidewalk and through the grass for about 70 feet before entering a single hole in the lawn just wide enough to poke a finger into. Many of the ants heading toward the hole were carrying white pupae and a few ants were winged. About a quarter of the ants were returning from the hole to which the others were heading, but none of those carried pupae. The migration went on until darkness fell, and maybe into the night.
The next afternoon a more diffuse march took place with about half the participants, but this time equal numbers going both ways, and no white pupae were in view. On the third afternoon all was quiet.
From information garnered on the Internet I find that colonies of these ants usually support several queens, and when a colony grows large it may split, so apparently this is what we saw.
Also I found a scientific abstract on research done on this ant's navigation system. They wondered how a wandering, foraging Pavement Ant, upon finding food, can make a straight line for its nest, not having to follow its scent trail backwards. They found that Pavement Ants could do this whether the day was sunny or cloudy. However, if they displaced the ant a certain distance, the ant would make a straight line toward the nest without taking the displacement into consideration. Therefore it was concluded that Pavement Ants use dead reckoning -- can somehow take into account all the rights and lefts they've taken during their wanderings, and maybe the time they've traveled, and in the end just know where home is.
Finding this information so easily reinforced my appreciation of the internet. What really blew me away, however, was this: When I went Googling using the keywords "Myrmicinae Tetramorium California," my own page consisting of the archived August 28,2005 Newsletter -- where I reported on yellowjackets preying on this species -- appeared on the very first page of results!
Nowadays nature-watchers like ourselves genuinely can contribute to the body of anecdotal information about the world's plants and animals. Once my archived newsletters are cataloged by search engines they become available to a whole world of nature lovers who may really value such information as Fred and I have been developing -- that sometimes yellowjackets eat Pavement Ants, and that sometimes they do whatever they did this week.