May is when the northern bobwhite quail hatch begins, but several steps must occur first. Nest construction starts by creating a small bowl-shaped depression in the ground and covering it with last year's vegetation to form a dome. The need for standing vegetation from the previous year is one of many reasons why grazing management is such an important issue when managing habitat for quail.
Once nest construction is complete, the hen will begin laying the eggs at an average of one per day. Bobwhite clutch size averages 12 to 14 eggs, but can range from seven to 28, decreasing as the nesting season progresses (Brennan 1999). Once all the eggs have been laid, either adult will incubate the nest. My own graduate research and many other studies have shown some females will breed with multiple males and nest multiple times. If the habitat is suitable and the weather is favorable, a female bobwhite may attempt to nest up to three times in one summer. This is one of the reasons why bobwhites seem to have boom and bust years. Incubation lasts 23 days, and all eggs hatch within a 24-hour period. The 23-day period is a long time for the nest and nesting adult to be exposed to predators, and it is absolutely amazing what can happen in that amount of time.
My graduate research investigated bobwhite nesting behavior and causes of nest failure. I used radio telemetry (Ag News and Views May 2006, Technology is Working For Wildlife) on 96 birds to locate their nests. Once a nest was located, I set up a continuously running infrared camera, allowing for day and night observations. I was able to record the behaviors of 35 different nesting individuals.
One of the more interesting findings was that evidence left after a nest predation event did not follow the current line of thinking. Previous thinking indicated that to identify a nest predator, the first rule of thumb is to check for nest damage. If the nest is not damaged and the eggs are missing, it usually means a snake ate the eggs. If the nest is destroyed and egg fragments remain, it usually means a mammal such as a raccoon or skunk was the culprit. Using the continuously running video recorders, we were able to disprove these theories.
We did have several examples that fit these scenarios. However, we had just has many examples that did not. There were multiple instances where coyotes, raccoons, skunks and badgers removed eggs one at a time, leaving the nest untouched. In several cases when eggshell fragments were left by a mammal, we observed the nesting adult removing the pieces from the nest and surrounding area. Without the cameras, we would have assumed a snake was the predator that caused the nest to fail. In addition to the incubating adult removing the eggshell pieces, we saw several examples of ground squirrels removing egg fragments from the nest when the adult was not there. As for the theory that says snakes will not damage a nest, we had examples of large bull snakes going into a nest and tearing it in half as they coiled around the eggs.
Considering these examples, I hope you think twice before determining the cause of a failed bobwhite nest. Something else to keep in mind is that just because a nest has been destroyed does not mean the adult has been killed. The best thing a person can do to improve nesting success is habitat management.
FYI: A new group of quail enthusiasts recently organized in our service area, the Arbuckle Mountain Chapter of Quail Unlimited. For more information go to their Web site at www.arbucklequ.com.
Brennan, L. A. 1999. Northern bobwhite. The Birds of North America, No. 397. The Birds of North America, Inc., Philadelphia, Pennsylvania, USA.