Posts Tagged ‘Aaron Kuehl’
Tuesday, March 27th, 2012
I woke up this morning with one question in my mind: Will the early arrival of spring produce more pheasants? To help me answer this question, I reached out to Pheasants Forever biologists Aaron Kuehl from Illinois and Jim Wooley from Iowa. While the guys made it clear there is no simple answer to my question, they did provide a number of reasons for optimism.
The recent mild winter was advantageous for a variety of reasons when it comes to setting the stage for a productive nesting season, but at the top of their list was hen health. Egg laying, nesting, re-nesting and brood-rearing are very taxing on hens. Consequently, a mild winter allows hens to begin the spring reproduction season in top shape with the ability to produce the maximum number of eggs per clutch (the average clutch size of eggs is 12). The math is simple; more eggs equal more chances for chicks, which provide better odds of adding more adult birds to the autumn population.
If a hen loses her nest due to cold weather, predation, haying, flooding, or some other disturbance, she will attempt to re-nest up to two more times. Each subsequent re-nesting attempt leads to a drop in the average number of eggs a hen will lay. A second effort will average eight eggs in a clutch, while a third re-nesting generally produces four to six eggs. As a result, the healthier the hens are coming out of the winter, the better the chances for nest success during these re-nesting efforts as well.
Let’s start with the basics of establishing a hen’s spring calendar:
Average Nest Initiation Date: May 1 (beginning as early as March 15 running through July 15)
Average Incubation Start: May 24 (beginning as early as April 1 running through August 1)
Average Hatch: June 15 (beginning as early as April 15 running through August 15)
So, if a hen begins laying eggs in a nest on May 12th, then incubation will start on May 24th if that hen stops egg production after the 12th egg drops. Then on June 15th, after 23 days of incubation without any complications, the chicks will hatch.
Photo period is the top factor influencing when pheasants begin nesting. In other words, the length of light in the day determines the bird’s nest initiation. However, according to Wooley, temperature is an influencing factor moderating the hen’s “decision” when to initiate nesting. Consequently, both Wooley and Kuehl believe the early spring could accelerate the pheasant nesting season by a few days.
“If you think about the reproductive calendar visually as a bell curve with the peak of the hatch traditionally occurring on June 15th, this early spring will likely shift that bell curve to the left a few days,” explained Kuehl.
Best Case Scenario
If the weather through April, May and June continues to be warm and relatively dry, then hen pheasants will have a high probably of pulling off successful first nesting attempts prior to haying season.
Worst Case Scenario
If hens begin incubating eggs earlier than normal and our spring weather turns cold and wet, then those eggs stand an uphill battle. Cold and wet spring weather generally leads to multiple re-nesting attempts, smaller broods and less than ideal chick survival.
Exceptions in the South and West
In the western United States and southern Great Plains, a cold spring isn’t a common limiting factor for pheasants. In fact, most western biologists will point to the need for spring moisture to “green” things up for insect production as the more important factor influencing their pheasant recruitment success.
The Mr. Mom Advantage for Quail
One major difference between pheasants and quail is the role males may play in the reproductive cycle. In some years, perhaps particularly when the density of quail is low, a hen may lay a clutch of eggs, and then leave her male bobwhite mate in charge of incubation duties for the next 24 days. Hens may then take up with one or more additional males. The male also assumes brood rearing responsibility once the eggs hatch (he has to—Mom is down the road with another boyfriend). Think about that; a hen quail could theoretically produce two or three broods during one nesting season with the assistance of different males. Consequently, quail have an increased ability to rebound populations quickly given quality habitat and optimum weather conditions during nesting season. In contrast, rooster pheasants play no role in their reproductive cycle other than hen fertilization, so each hen can, at maximum, produce one brood.
Habitat is the Key
Ultimately, we can’t control the weather and it will always be a wild card in the equation. However, we can control the quantity and quality of habitat on the landscape. Habitat is the key to providing hens with the places they need to successfully nest and raise broods.
The Moral of the Story
Weather conditions are lining up well to produce a very good spring nesting season for pheasants that will likely begin earlier than normal. Keep your fingers crossed the warm conditions will extend a couple more months.