Birds and an Ant Army in Southern Tamaulipas

Field: Agricultural and Biological Sciences (Life Sciences)

TAM.4ULIPASwoodland along the Rio Sabinas, near the hill village of Ctimez Farias, in southwestern Tamaulipas, I was afforded a remarkable and wholly unexpected opportunity to observe certain Mexican birds which I had many times heard but never very satisfactorily seen.Chief among these were the Barred Ant Shrike (Thamnophilus doliatus) and the Red-throated Ant Tanager (Habia gutturalis), forms which reach their northernmost limit of range in or near that area.I had devoted that day almost exclusively to hunting Groove-billed Anis (Crotophuga sulcirostris), a species well known and common thereabouts, but unaccountably hard to find at the moment.My M.exican friends called these birds garrapateros-tickbirds.The matter was urgent, for this was to be my last full day in the low country along the Sabinas and several specimens were needed.Midafternoon was not, admittedly, a good time for bird hunting, but I reasoned that if I found the anis at all they would probably be sitting quietly in the shade and easy to obtain.Bearing in mind that I had often seen anis near livestock, I visited all the places at which I knew cattle would be resting at that time of day.But not a single ani did I see or hear.Refusing to give up, I decided to concentrate upon the place at which I had shot a specimen that morning.There, I recalled, the bird had flown southward from a clearing into the shrubbery, and I had heard another calling farther to the southward in the thicket.This was not a comforting thought.It was tick season and I knew the young ticks, the dread pinolillos, would be especidly numerous in the dense, tangled mats of wild pineapple.Following a straight, little-used trail a1ong.afence, I eventually came to a freshly cut property line leading south.The a.ir was soft and hot.I could see tiny ticks crawling up my pants.Some of these I brushed off vigorously.How shut-in and apart from the rest of the world the thicket seemed!Suddenly, some rods off in the tangle, I heard a most welcome sound, the clear-cut pee-to of an ani.I started straight through the thicket, but quickly changed my plan partly because of the thorny vines and partly because I heard another ani calling nearer at hand and in a different direction.Returning to the property line and following it, I presently saw three anis fly up, then a fourth.The last was the closest of all.It did not seem shy and I had little trouble approaching it.As I shot, the other three flew off, disappearing to the northward.I retraced my way along the property line, pausing frequently to listen.When fifty yards or so from the place at which I had shot the bird, I was surprised to hear a sharp pee-to very near me and to see five or six anis hopping and flying southward through the thicket.Confident that I should be able to obtain more specimens if only I could keep track of the flock, I started after them.All at once anis seemed to be all about me, hopping through the shrubbery and calling excitedly.Soon I had my six specimens and needed no more.The living anis, instead of flying off as I had lxpected them to, continued to stay close by, and their behavior puzzled me greatly.At first I thought they were merely curious.Then, watching them closely as I held one of the specimens toward them, I fancied reading suspicion and resentment in their behavior.I could not remember ever having seen wild, free-flying anis at such close range.The sensations of the next few seconds were so vivid, so wholly unexpected, and followed each other in such rapid succession, that they were-and I use the word realizing that it hints of hyperbole-semiparalyzing.I stood there as if transfixed, as if