Understanding waterfowl
Liberal Seasons? How?
Spring habitat conditions suggested shorter waterfowl hunting seasons and bag limits this year. What caused the USFWS to offer less-restrictive regulations?
By Bruce Batt, Ph.D.
Many hunters (and biologists) were surprised in August when the U.S. Fish and Wildlife Service (USFWS) decided that the states would be offered liberal hunting season frameworks in each of the flyways. The news since last winter about poor conditions on the breeding grounds had pretty well prepared everybody for shorter seasons and smaller bag limits. Ducks Unlimited is not involved in the regulation-setting process, so we were initially caught a little off guard, too. However, closer inspection reveals the underlying reasons for the USFWS ruling.
Some background information is needed to explain a few basic issues. First, the primary data used to determine season lengths and bag limits are breeding waterfowl numbers and breeding habitat conditions. The Canadian Wildlife Service and USFWS collect this information in May through surveys that have been conducted on the same survey areas since 1955. Second, until 1995, managers annually debated regulatory alternatives without a structured framework to help guide them to decisions. The debates were often heated, divisive, and driven by two opposing schools of thought. One maintained that hunting harvest is compensatory mortality that has an insignificant effect on subsequent breeding duck numbers, and that, unless populations are exceedingly low, other causes of death will take birds not harvested by hunters (see sidebar). The other school believed that hunting is additive to other forms of mortality; thus, protecting birds today will mean more for tomorrow.
Managers found themselves in two camps: those who wanted to maximize hunting opportunity, which the additive school usually views as too generous; and, those who thought we should minimize risk to future duck populations by restricting hunting seasons, which the compensatory school usually thinks is unnecessarily restrictive. Evidence supporting either end of the spectrum has not been conclusive enough to resolve the argument.
Significant progress could not be made on this dilemma unless a different approach was developed. In 1995, the USFWS and the states agreed to a system of setting seasons known as Adaptive Harvest Management (AHM). AHM explicitly sets out to annually improve managers’ understanding of whether the types of seasons (season lengths, bag limits, etc.) selected result in harvest that is additive or compensatory. Another uncertainty being resolved by AHM is determining how the density of breeding ducks affects their productivity. Every season is different because duck numbers change each year, and breeding ground conditions are variable, as is the weather during the hunting season. Thus, each year, managers learn more about the effects of harvest on breeding duck numbers and production, and each year the scientific basis for setting seasons gets a little stronger—just what biologists were trying to accomplish when AHM was developed in the first place. However, the AHM model is, by definition, a “work in progress” and, so far, the system has only been exposed to relatively high numbers of breeding birds, good breeding grounds conditions, and better than average fall flights. Managers now stand to add greatly to their understanding of these relationships because most of the elements are different this year than the conditions under which AHM has operated to this point.
A key element of the AHM system is an annually updated matrix of hunting season prescriptions that are driven by the size of the current mallard population and number of May ponds counted on the Canadian prairies. Mallards are used because managers have the best data on this species. Large numbers of mallards are banded each year to provide information on survival and mortality rates. Mallards are also thought to be somewhat of an “average” duck, with biological characteristics that are similar to other ducks in the harvest. In 2002, the mallard population was just above the level where a moderate season would have been prescribed, and the matrix thus called for a liberal season. That is, even though breeding populations are down and prospects for production are not very good, the substantial number of breeding mallards going into 2002 has resulted in their numbers remaining above the liberal/moderate threshold. (The AHM matrix provides criteria for liberal, moderate, restrictive, very restrictive, and closed seasons—each choice reduces the number of days during which hunting is allowed and the numbers of birds allowed each day.) Thus, the USFWS offered the liberal hunting season framework using AHM, the process developed in cooperation with, and endorsed by, the flyway councils and in use since 1995. To offer anything else would have opened the door for renewal of the old process that previously inhibited the advancement of solid scientific criteria for harvest management.
Because Ducks Unlimited has no regulatory authority, it is not a participant in setting regulations. However, DU does support the idea of managing waterfowl by the most objective and scientific methods available. This is the standard that DU sets for its own work on habitat conservation programs throughout the continent. AHM is the process agreed upon by those federal and state agencies charged with deliberating and setting waterfowl hunting seasons. Ducks Unlimited is in no position to second-guess AHM and the decisions made this year. We support the process and will continue to assist where possible to continually improve the science on which it is based.
The frameworks offered by the USFWS have other special considerations designed to either protect other species besides mallards, such as scaup, pintails, and canvasbacks, or to allow additional harvest for abundant species, such as snow geese. In addition, regulations are used to manage hunters as well as ducks. Thus, once the season frameworks are offered to the states, each one decides how its individual circumstances and needs with respect to hunter management might modify what it chooses to allow for season lengths, bag limits, opening and closing days, split seasons, and other special considerations. Individual states can be more restrictive than the USFWS, but not more liberal. For example, a severe drought in the Southeast has caused South Carolina to shorten its season and reduce the bag limit to protect “their” birds a little more. Arkansas chose to reduce its mallard limit to provide added protection for the birds that come through that state. California reduced season length and bag limits in recognition of the severe drought in areas of the West that provide many locally produced mallards, but are not part of the annual USFWS survey.
A critical point here is that this system is adaptive and will respond to new or improved information as it becomes available. In fact, the system is explicitly designed to generate such information, which can, in turn, be used to improve the system. AHM is not perfect, but the important thing is that it provides a mutually agreed upon framework for progress. In the end, hunter satisfaction this year, as every year, will be driven by a number of factors, chief among them weather and local habitat conditions. That lesson has been made clear during the past couple of seasons. Regardless, managers will learn more because the AHM framework is in place than they would have without it, and future hunting seasons will be based on an improved base of knowledge with each successive year.