The Maryland Department of Natural Resources (DNR) announced in June its intent to eradicate the state’s mute swan population by “reducing it to as low a level as can be achieved.” The DNR blames the swans for excessive consumption of aquatic grasses and the subsequent degradation of the Chesapeake Bay watershed, though ecologists point to polluted urban and agricultural runoff as the real culprit. The Department has been killing mute swans since 2003, causing their numbers to plummet from more than 3,500 in 2002 to less than 500 today. The ecological impacts of a mute swan population numbering in the low hundreds, however, have not been examined.
The Animal Welfare Institute (AWI) and other advocates criticize the DNR’s decision to eradicate the swan population, as well as its past and current actions, for being devoid of transparency. Though the DNR established a Mute Swan Advisory Committee earlier this year to recommend the best way to manage the state’s mute swans, the Department continued to secretly kill the birds while the committee was still deliberating. AWI wildlife research assistant, Serda Ozbenian, attended and provided written and oral comment at the committee meeting in April. Although population estimates were discussed, the DNR neglected to mention that swans were being killed. The brutal methods used to kill the swans have also been concealed from the public.
The DNR admits to killing the swans by either gunshot, or crushing and separating the cervical vertebrae (cervical dislocation) with an emasculatome—a device designed for the sole purpose of castrating livestock. The Department claims this method is accepted as “humane” by the American Veterinary Medical Association (AVMA). However, the AVMA Guidelines on Euthanasia considers cervical dislocation to be a “conditionally acceptable” method that “by the nature of the technique or because of greater potential for operator error or safety hazards might not consistently produce humane death.” The AVMA elaborates that the use of this method requires a high degree of technical proficiency to ensure a rapid loss of consciousness and should be “limited to poultry, other small birds, mice and immature rats and rabbits,” since the large muscle mass in the cervical region of larger animals makes dislocation more difficult. The AVMA also recommends that large birds be anesthetized prior to euthanasia, contrary to DNR procedures.
Research is needed to determine if this small population of animals is having a significant effect on the ecosystem before a so-called "management” plan is implemented. The state should assess the impacts of runoff and establish a plan for addressing its serious negative impacts on the Bay. If swan management is deemed essential to protect the bay ecosystem and other species, every effort must be taken to reduce the population by compassionate means. AWI offered to assist the DNR in developing appropriate standards, but the offer was ignored.
Until the impact of the swans on the ecosystem can be assessed, AWI prefers the process of egg addling—a method of reducing further population growth by which eggs are removed from the nest, embryo development is terminated, and the eggs are returned to the nest. Though the Department already practices limited egg addling, a more aggressive effort with help from a group of trained volunteers should be employed as an alternative to killing the animals.