Management Problems and Solutions
Few subjects generate as much concern and misunderstanding among pheasant hunters as predators and their impact on pheasant populations. Much of this concern is focused on the very visible loss of adult pheasants (by foxes, hawks and owls) in the population. However, pheasant nest mortality, mostly by mammalian predators, also significantly impacts pheasant populations. Avian predators, such as hawks, crows and owls, also destroy nests and may kill adult birds, but they account for less than 10% of the deprecated adults and nests.
No single predator gets more blame than coyotes, but research over several decades has proven that coyotes focus their foraging on rodents and rabbits and do not take adult pheasants or nests as frequently as the other mammalian predators (red fox, striped skunk and raccoon). In addition, the larger home range and territorial nature of coyotes can actually result in lower populations of these other, more destructive predators. Predation accounts for three-fourths of unsuccessful nests, and nearly all of adult mortality (excluding hunting) is directly predator related. The problem can be exacerbated when insufficient habitat and severe weather make pheasants more vulnerable.
This publication, produced in cooperation with Dr. William Clark of Iowa State University, examines the most common methods used by wildlife professionals to reduce the detrimental effects of predators on game bird populations.
A small scale remedy
Early attempts to decrease the impact of predators focused on reducing the number of predators, mainly through trapping. These efforts are effective for small areas but are dependent on three important factors.
First, trapping efforts must reduce nest predator populations during the key period of recruitment -- beginning prior to, and continuing throughout the entire nesting season (approximately 100 days). Second, trapping needs to extend beyond the boundaries of the controlled area. Most nest predators have large home ranges and if trapping efforts fail to account for this predators from surrounding areas will still negatively impact nesting success within the controlled area. The most important factor in a successful removal program is a professional, full-time effort. The occasional removal of individual animals by hunters has very little impact on predator populations and trapping efforts that rely on bounties are destined to fail.
It is important to understand that sustained trapping efforts tend to stimulate reproduction by predators (compensating for artificially low densities) and create populations with proportionately more juveniles that wander more across the landscape thereby increasing the chances of encountering pheasants.
The pros and cons of fencing
Predator fences have significantly increased nesting success for some species (mostly waterfowl) in very limited areas. Each spring before the nesting season, predators must be removed from inside the exclosure by intensive trapping or these fences are ineffective. In fact, poorly designed enclosures may actually lower nest success rates if predators are trapped inside. Unfortunately, the costs ($22,000/year) of constructing and maintaining a 40-acre exclosure, exceeds the benefits for most species, and other non-economic costs plague exclusion methods. Pheasants, for example, sustain brood losses when attempting to exit exclosures.
More habitat, less predation
Recently, wildlife managers have looked to less-expensive methods to improve game bird populations and especially their nesting success. They have focused on the amount of habitat (composition of the landscape) and the arrangement (configuration) that increase nesting success by reducing the effectiveness of predators. Well-designed habitat projects can reduce predation by up to 80 percent.
Composition, or the amount and type of habitat, has the greatest effect on game bird populations. In highly agricultural landscapes, pheasant numbers increase as the percent of area in grassland habitat rises. Potential population gains are greatest in areas with very little grassland habitat (less than 10%), but increasing the grassland area is beneficial even up to levels of 50%. Population size increases because of additional nesting birds, and a significant increase in nesting success. Populations tend to build up where there is substantial habitat but most importantly, they recover more quickly after cool, wet springs or severe winters. Larger patches of nesting cover (> 40 acres) have significantly higher rates of nest success than smaller sized patches. For example, in agricultural landscapes where the primary form of grassland habitat is road and drainage ditches, predator activity is concentrated on those smaller strips of cover. In landscapes having a greater component of grassland habitat, predator activity is diluted throughout the many patches of habitat. In addition to diluting predator activity, the efficiency of predators in high grassland landscapes is reduced.
Cover quality is also important. Dense blocks of undisturbed cover, such as CRP that is not mowed or grazed, are the most effective at reducing predation. Dense mixtures of grasses and forbs offering good residual cover after winter are highly selected by pheasant hens because they conceal nests from both avian and mammalian predators.
There have been very few studies on the influence of habitat configuration on predator activity and subsequent nesting success. Shape and arrangement of habitat patches, however, does influence the hunting efficiency of predators. For example, nesting habitat near substantial woody or abandoned farmsteads experiences higher nest mortality due to an increase in raccoon and skunk activity. These areas may also attract avian predators. Mammalian predators often enter and exit patches of habitat at corners, therefore large blocks with relatively few corners could lead to an increase in nesting success. Wide linear habitats of at least 100 feet on each side of steams and waterways are more difficult for predators to search than much narrower road ditches. While a standard configuration for an overall decrease in predator activity has not been identified, configuration should always be considered in a habitat project.
Predators have historically been and will continue to be the principle decimating factor for pheasant nests and adult birds, as they are for all other small game species. This is neither unusual nor unsolvable. Through sound management we can significantly reduce the detrimental effects of predators. This can be accomplished in two ways, 1) reduce the predator population (remove or exclude), or 2) reduce their effectiveness (dilute). While predator removal and exclusion methods can increase nesting success on small areas, these methods are too expensive for use on a landscape basis and do not significantly increase the number of nesting birds over the long term. Through the addition and management of habitat, we not only decrease the impact predators have on existing nests, but also increase the number of nests and population size in an area. Increased and improved nesting habitat also provides escape cover for pheasants from avian predators while the other methods do not. Furthermore, we have increased habitat for other non-target wildlife species as well as hunting opportunities for ourselves at a fraction of the cost of predator reduction methods. Predators will continue to eat hens in winter and nests in spring, but weather and habitat conditions will drive population fluctuations.
Need more information about enhancing pheasant populations?
Then try the Pheasants Forever Essential Habitat Guide—a handy reference on all kinds of pheasant cover, including shelterbelts, food plots and nest cover. And, be sure to check with your local Pheasants Forever chapter, where you will find cost sharing, planting assistance, or just advice from a friendly chapter volunteer.
Many of the photos provided are courtesy of Roger Hill.