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June 1, 2001

By Dale Rollins
Extension Wildlife Specialist

Follow these rules of thumb...

As a youngster I can remember my Dad telling me that a rule of thumb for estimating the worth of one's horse was to see how many times he rolled in the dirt after a hard day's ride. He estimated the horse was worth $50 for each roll. The best mine ever did was about $300 (1965 dollars).

Rules of thumb are kicked around in various circles. Sometimes they're based on good information, while others (perhaps the horse tale) may just be hearsay. While wildlife management recommendations are often site-specific, certain rules of thumb are useful. Here's an assortment of guidelines for situations encountered in Texas.

Deer

A yearling doe will have a single fawn, but older does will have twins. Perhaps 10 percent of the fawns in a given year will breed, and they will breed in January or February. Only about one-third of the fawns born in a given summer will see their first birthday. A buck's antler growth will peak out at about seven years of age. A deer will consume about 3 percent of its body weight daily in forage. A buck will lose about 25 percent of its body weight from November through January due to the rigors of the rut.

When conducting helicopter counts, the pilot should count twice as many deer as the inexperienced observer does. Helicopter counts usually suggest a deer density about half that obtained by spotlight surveys. If you conduct a helicopter count in October and count more coyotes than deer fawns, consider intensive coyote control the next year to increase fawn survival.

When deer hunting, the "shot rule" allows a distant listener to ascertain whether his buddy bagged a buck. One shot, one deer. Two shots, maybe one deer. Three or more shots, no deer. Not applicable to black powder hunters! And it doesn't work worth a hoot for bow hunters!

Quail

A bobwhite quail has about a one in three chance of nesting successfully. A good quail year hinges on a June hatch; at least 50 percent of nests should hatch during this month. Bobwhites will nest in little bluestem about the size of a basketball if such plants are available. Quail that nest in prickly pear will have about twice the success of those that nest in grass. Nest depredation will be low (e.g., 50 percent) if a hen has the opportunity to choose from more than 250 suitable nest clumps per acre. Out of 100 quail eggs, perhaps four will produce an adult quail. Most quail will die within a quarter mile of where they hatch.

Roosters will incubate about 25 percent of the nests in any given year. Hens are about 20 percent more likely to be in the hunter's bag than are roosters. If fewer than half of the quail you bag are young birds (i.e., hatched the previous summer) hunting will be tough. If you can flush a quail three times within 10 minutes, you can walk up and catch it on the ground.

You should be able to throw a softball from one "quail house" (i.e., loafing cover) to another for optimum quail habitat. A good broomweed or sandbur year usually translates into good quail numbers. An afternoon quail hunt will generally produce about 50 percent more covey flushes than a morning hunt. You will get a shot at only about one-third of the quail on a given piece of property on any particular day. If your hunting party averages more than two birds bagged per covey flushed, you've had a good day. A quail lease (dollars per acre) should be worth about $2 per acre plus 10 cents per covey flushed in an average day (i.e., a 20-covey day average would be worth about $4 per acre).

Feral hogs

There are two kinds of Texas landowners—those who have feral hogs on their property, and those who will some day. The average litter size of a feral hog may be four to five pigs, but eight survive. Whenever a feral hog hunter tells you his trophy boar weighed a certain amount, divide that amount by two and you'll be pretty close.

Food plots and feeders

To be effective in supplementing wildlife food needs, you should figure on having 2 to 5 percent of your land in wildlife plantings. Perhaps the best combination of species (across Texas) is wheat and milo. Plant the outer one-third to milo and the inner two-thirds to wheat. At least west of the 100th meridian, remember that when you need food plots you can't grow them (dry weather) and when you can grow them (wet weather) you probably don't need them. If you're feeding wildlife, perhaps half of the feed winds up in your target species (e.g., deer). Nontarget species (i.e., raccoons) will get the rest. Feeding programs will not be cost effective using traditional economics. My bottom line is that if you want to feed, and can afford it, feed.

Rules of thumb are usually mixtures of biology and experience. If you've got some good ones relative to wildlife, drop me a line:

Dr. Dale Rollins, TCE
7787 U.S. Highway 87, San Angelo, TX 76901
d-rollins@tamu.edu (e-mail)