To the Editor:
We write in response to Ethan Bogdan’s editorial about the deer cull planned for the Crum Woods. There are several points raised within his piece that require either clarification or correction.
First, a bit of background on how this decision was reached. Swarthmore College has been studying the long term effects of an overabundance of deer since 2001 when it commissioned Natural Lands Trust and Continental Conservation to prepare a Conservation and Stewardship Plan to secure the long-term viability of the woods and identify any potential risks or hazards. That report, published in 2003, concluded that the effect of overpopulation of deer in the woods was “profound.” Further research done by Natural Resource Consultants Inc. (NRC Inc.) and an aerial infrared deer count supported the conclusion that managing the deer population was a priority for maintaining a healthy ecosystem in Crum Woods.
At present, excessive deer browsing is severely limiting the ability of the forest to regenerate naturally and is altering the structure and composition of the forest. For example, deer are consuming nearly all of the native oak saplings. As old oak trees age and die, there are fewer and fewer younger trees left to grow and fill in the canopy, and as a result the available habitat for other animals is diminishing. Non-native plant species that are not part of the natural deer diet are replacing the native species in the woods.
The Crum Woods Stewardship Committee (CWSC) set out to understand how best to reduce the deer population to a sustainable size in a safe, science-based, and socially responsible manner. The committee members gave careful consideration to many options, including taking no action, mitigation techniques, predator restoration, trap and transfer, contraception, trap and euthanize, recreational hunting, sharp shooting, and/or a combination of these tactics. The CWSC hosted several public forums throughout its deliberative process in order to keep the community informed of its findings and to listen to community feedback.
It was only after careful study of the woods, consideration of a wide range of deer population management options, and engagement with the community on this issue that the CWSC came to its recommendation to proceed with a cull.
Immunocontraception, as Ethan proposed, is a tool that we will reconsider once it is approved by the EPA, is commercially available and has been tested in open environments like the Crum Woods. At present, GonaCon is not commercially available and we do not have a clear and dependable timeline of when it will become available. Promises that practical nonlethal solutions are on the near horizon have been forthcoming since the mid-1970s, and statements that GonaCon will be commercially available in the imminent future began early in 2006. We are now approaching 2009 and simply cannot wait any longer.
Even if GonaCon were available right now there is a lack of experimental data supporting GonaCon’s efficacy in an environment such as Crum Woods. Many of the current testing grounds are islands or enclosed areas, not representative of the free-ranging deer populations such as those inhabiting the Crum Woods. It is also worth noting that a typical deer life span in the wild is 18 years, and thus contraceptive methods would at best only result in a very slow decline in the population, perhaps requiring a decade to have a noticeable impact.
While the Crum Woods may be in better health than other areas with overabundant deer populations, that does not mean that the Crum Woods is “not yet in a critical condition” as Ethan’s editorial suggested. The longer the forest is impacted by overabundant deer the more significant will be the negative consequences and uncertainty regarding potential for recovery. At present we are unable to secure land management grants for the Crum Woods because of the threats imposed by an overabundant deer population. We are also unable to replant native plant species in the quantities necessary because of the number of deer.
Regarding the arguments against the use of a sharpshooter, it is first important to note that the College intends to contract an expert for this purpose. We must also clarify that adult female deer will not be the only target. The sharpshoot will target all the deer within a group in order to prevent learned behavior by any particular segment of the deer population.
Fawns will be six months old or older when the cull is planned to take place and they will no longer be dependent on the doe. These animals will be indistinguishable from adults for most people and will be old enough to breed. There is little objective science to support the conclusion that fawns experience emotional or physical suffering as a result of being separated from the doe at this age. In fact, they are driven off by the doe in the spring as the dame prepares to give birth to new offspring.
In environments with intense competition for food a sudden drop in population (as would occur after a cull) will sometimes result in a phenomenon known as “reproductive rebound.” Science has shown that reproductive rebound—wherein fawns breed at younger ages and there is an increased occurrence of multiple births—is unlikely to occur in the Crum Woods setting. The number of fawns born into a herd each year is influenced by a number of factors, the most important being nutrition. Deer in the Crum Woods are well nourished, due to the ready availability of ornamental plantings, fertilizer, lime, mown lawns and bird feeders in the surrounding area. Furthermore, the management program outlined for the College calls for on-going population monitoring and control, which for the foreseeable future will include the annual removal of deer to maintain a healthy population.
The College remains open to considering alternative methods for balancing deer impacts with the interests of the other plants and animals that make up the forest as new options become available. At present we have determined that a cull conducted by an expert sharpshooter is the only option that meets our goals to reduce the deer population to a sustainable size in a humane, forest-science-based and socially responsible manner, in our open boundary woodland setting.
Jeff Jabco and Colin Purrington
Co-Chairs of the Crum Woods Stewardship Committee