Hawks and Quail

The first type is the buteo hawk, exemplified by the ever common red-tailed hawk. Buteos are described as "B-29s", i.e., slow, lumbering, but powerful adversaries. You see them perched atop a telephone pole, or an old snag. They kill all the quail they can catch, but they're just not designed to catch very many quail. Rodents are the mainstay of their diets.

The second group of hawks, the accipiters, is the quail's most feared natural enemy (my opinion). The two most common accipiters in Texas are the Cooper's hawk and the sharp-shinned hawk. You hardly ever see these birds perched out in the open; when you see them they're darting through the mesquite trees well ahead of you (hence one common name, blue darters). In aircraft jargon, accipiters are the F-16s; they're designed for air to air combat and are among the most proficient predators of quail. They feed almost exclusively on birds.

There is a third group of hawks relative to quail predators: the northern harrier, more commonly known as the marsh hawk. These hawks cruise at low altitudes as they quarter across the landscape. Harriers are among the most common hawks during winter months in west Texas. You'll remember them by the white rump patch that's quite visible and their rather blunt facial profile when in flight. Like the accipiters, you rarely see them perched; they're seemingly always in flight. In our aircraft analogy, I consider them as the A-10 Warthogs (the famed tank-killers in the Gulf War).

I've seen quail killed by each of the three kinds of hawks. At the 3rd Battalion of the Bobwhite Brigade, and again in the 9th, cadets recovered radio transmitters from nests of red-tailed hawks. It may be noteworthy that both instances involved pen-reared bobwhites, not wild birds. I observed a Cooper's hawk actually catch a flying bobwhite hen right outside my pickup window once in western Oklahoma. And I witnessed a narrow escape of a blue quail from a Cooper's hawk a couple of years ago near Ft. Stockton. Quail pursued by accipiters are typically shrieking as they seek to get away.

But I've flushed more northern harriers off of quail carcasses than any other species of hawk. I can recall five such instances, one just a month ago. While harriers are likely intermediate in their skill at catching quail (behind the accipiters but ahead of the buteos), they assume the role of number one avian quail predator in west Texas because of their abundance.

Back in January of 1943, Texas Parks and Wildlife biologist A. S. Jackson studied quail in Cottle County and described how bobwhite populations on his study area crashed "with explosive suddenness and all but remnants were lost to predation" between 7 - 15 January 1943. He conducted transects to estimate the amount of mortality that had occurred and concluded "everywhere the ground was littered with evidence that predation had been recent and terrific." Northern harriers, red-tailed hawks and Cooper's hawks were the raptors involved, but Jackson concluded that northern harriers were the only raptor species abundant enough in that area to have killed so many quail. Four of 18 northern harriers examined had consumed bobwhites. Jackson reported that evidence of predation on blue quail was "light" and that blues were apparently less vulnerable to avian predation than were bobwhites.

Studies in the southeastern U.S. using radio-collared bobwhites typically find that raptors are responsible for about two-thirds of the annual mortalities with mammalian predators accounting for the rest. One study we did west of San Angelo back in 1994-95 saw just the opposite trend. But our study followed quail from March through August, and mammalian predation tends to peak during summer months. Raptor predation typically peaks during winter months (likely due to the higher abundance of wintering harriers and accipiters).

The most intensive study of quail in the Rolling Plains was conducted from 1991-1997 on the Packsaddle Wildlife Management Area in western Oklahoma. The long-term telemetry study provides a long-term data set on quail happenings. As with any quail telemetry study, you learn some interesting things on nesting sites, reproductive strategies (e.g., "double clutching"), movements, and mortality sources.

Bobwhites at the Packsaddle WMA survived at an annual rate of 20 percent. Predation was the primary cause of mortality; 37 percent of the mortalities on an unfed site were avian-caused and 28 percent mammalian. On a paired site that had supplemental feeders, 44 percent were killed by hawks and 26 percent by mammals. Hunters accounted for 15 percent of the mortalities.

Harriers sightings were significantly correlated to quail mortalities on both fed and unfed sites, and harrier numbers explained over half (53 percent) of the variation observed in quail mortalities. Curiously, coyote abundance was negatively correlated to quail mortalities, i.e., quail tended to survive at higher rates in areas of greater coyote abundance.

I remind you that all hawks are protected by state and federal laws. The manager's only legal recourse is one of habitat "ergonomics", i.e., structuring the habitat to allow the quail to work more efficiently while disrupting the raptors' search efficiency. By arranging the hula hoops (quail houses) with some forethought, the Bobwhite Brigaders learn that brush can be sculpted to frustrate the quail's enemies. That blueprint includes adequate ground cover, screening cover (e.g., catclaw mimosa), and well-distributed quail houses (no more than a softball throw apart).

One of the first things I tell cadets at the Bobwhite Brigade is that a quail's life, indeed every living, breathing moment, is dictated by the threat of predation. As we seek to increase quail numbers, it behooves us to think like a quail . . . every day of the year. Consider their plight as you plot and plan your range management strategies for the New Year.