Nature Notes is produced by the Chihuahuan Desert Research Institute and Marfa Public Radio and is sponsored by the Meadows Foundation and the Dixon Water Foundation. Tune in to Nature Notes on KRTS-93.5 FM on Tuesdays and Thursdays at 8:35 a.m. and 4:45 p.m. and again on Thursdays at 7:06 p.m.
In the Chihuahuan desert one species of hawk, the Harris Hawk, hunts in packs, chasing down jackrabbits. Young Harris Hawks will stay with their parents as one year olds, helping to hunt for this yearâ€™s hatchlings. The Harris is the only hawk in the world that has these two behaviors. How can you identify a Harris Hawk?
The Harrisâ€™ hawkâ€™s full name is Parabuteo unicinctus harrisi (Audubon); itâ€™s is the only member of its genus, whereas Buteo, or buzzard, has 10 members in this country. Parabuteo means “nearly a buzzard.â€ Unicinctus refers to the single broad white band on the rump, which makes the bird so easy to identify.
Audubon named the bird after his friend Edward Harris, a New Jersey gentleman farmer and amateur ornithologist, whom he met in 1824 and who became his benefactor and traveling companion. Later Audubon honored him again with the name Harrisâ€™ Sparrow, and although he was not the first to describe the sparrow, the name persisted.
The Harrisâ€™ Hawk ranges from southern Argentina and Chile, west to the Pacific. In the United States, it is only found in southern Arizona and in the Chihuahuan Desert of West Texas and southern New Mexico and a bit beyond its northern edge. The first speciman was collected in Louisiana (where Harris Hawks are no longer found).
The Harris Hawk may wander somewhat in groups in the fall but does not truly migrate. It cannot be found in mountains or woods or on open, grassy plains, but prefers a mesquite-covered pasture. As the Southern Llano Estacado became covered with mesquite, Harrisâ€™ Hawks might have spread northward. However, a pamphlet published in 1950 mentions a few common birds in Midland County in 1916. Three nests of Aplomado Falcon and thirty-eight of Swainsonâ€™s Hawk were found, but no Harris Hawk.
All observers have noted a propensity of the Harrisâ€™ Hawk to perch quietly for much of the day rather low in the mesquite near its comrades. The hawks have been called sluggish, but they soar or hurry just over the top of the mesquite when hunting. Theyâ€™re tame because most donâ€™t see many people in their mesquite empire. Years ago students from Cornell University took nestlings for an experiÂ¬mental program in hawk breeding. Their leader, who helped the students find nests, reported that they did not encounter any opposiÂ¬tion from the parents. The young birds eagerly accepted the chunks of raw chicken that the students fed them with tweezers.
Harrisâ€™ Hawk is no menace to chickens here because there are practically no chickens in its habitat. Small birds are common in the mesquite and west Texas birders have seen a Harrisâ€™ hawk flying with a house finch dangling from its talons. New Mexicoâ€™s Stanley Ligon said the hawk makes up for such “crimesâ€ by eating rodents that would otherwise eat much of the seeds on which Finches feed. Some say Harrisâ€™ Hawks eat wood rats, but the rats are nocturnal, so the hawk would have to be lucky to catch them.
For years West Texas was the rabbit capital of the world due to the control of bobcats and coyotes. Rabbits are the main food of Harris Hawks, and one can find rabbit entrails and other remains hanging in the mesquites. In the 1980â€™s it was discovered that Harrisâ€™ Hawks hunt rabbits cooperatively. Family groups of three to seven work together, taking turns chasing the rabbits, and even land and run under a mesquite to chase the rabbit. They then share the spoils.