Problems with tubal ligation

A September 29, 2014 Washington Post argued that a sterilization program was unsuccessful because does went into heat and attracted more bucks.  See comments below  
A Surprisingly Useful Tool for Deer Management?   Anthony DeNicola Ph.D., 
President, White Buffalo Inc.

The Sept. 29 article by Jackson Landers entitled “Trying to limit the number of deer with surprising results,” is misleading. I was a reviewer on the Cornell publication and have been in the wildlife discipline for 27 years. Since 2009, my non-profit has conducted over 500 ovariectomies and has managed the cost down to ~$500/deer. On study sites, we’ve seen reductions of up to 30% in Year 1.  It dismays me to see an article like this when sterilization is a tool we hope to use in suburban environments where lethal methods are neither feasible or practical, or as in Cornell’s case, used in conjunction with lethal methods to more rapidly reduce populations.  The article mentions that birth rate and doe numbers declined. There were additional bucks, but in addition to multiple estrus cycles attracting bucks, the subsequent camera surveys were conducted over bait post-rut and in a refuge surrounded by hunting. These details alone would concentrate bucks and inflate the estimate. It is likely that most males don’t reside year-round on campus, so the documented decline in females actually was successful.  The "effectiveness" of the subsequent hunting harvest on campus was emphasized, but if they had not sterilized the females, that spring’s new fawns would have negated the 45% harvest. It is critical that we have every tool available to manage over abundant deer populations in developed areas and not prematurely dismiss a potentially viable technique.

More from Anthony DeNicola

I am not anti-hunting, but after years of dealing with issues in this discipline, I know that once a community gets to a place where they have a problem (and many across this country are beyond there), hunting alone has not been able to help them achieve goal densities.  It is critical to recognize that deer are already firmly entrenched, in ever increasing numbers, in these densely populated environments and the conflicts are growing. While bucks may move more broadly in the landscape, the does are settled nicely into neighborhoods, and year after year, they live, breed and die within the same small area.You will not be able to make a difference by sitting in a tree stand in an outlying area.Since the environment is suburban, access issues are a given. If it isn't discharge restrictions, homeowner concerns or true safety issues, in all reality, you will simply not be able to access enough animals to help a community reach its goal, and a smarter, more wary herd will be the result. We’ve certainly seen nontraditional methods like planned culling work, but that requires a commitment from the community and landowners, and does require ongoing work to keep the population from growing.

Current research shows that even with longer seasons, additional access and unlimited bag limits, hunting alone hasn’t been able to manage populations down.  If you read further about Cornell, you’ll find that even hunting on the Cornell campus has failed to meet goal densities after 5 years. They have given access to all the lands, and haven’t even come close to meeting goals.  We’ve just seen Block Island begin to offer a $150 bounty per deer. If hunters are really willing to do the work for the cost of the projectile, why is this starting to happen?

The issue with deer in suburbia is not as simple as allowing hunters to come in and shoot for free. Each area needs a different strategy that factors in densities, areas of concerns, social issues and a variety of other things.  Perhaps, if you pair hunting with sterilization, there may be some hope of achieving goal densities in appropriate communities.  That’s what the Cornell work actually showed.  The unfortunate thing is that people are focusing on the sensationalized “buck magnet” angle.

The good news with sterilization is that it does appear to be working.  We are still assessing immigration rates, but are seeing declines of up to 30% in the communities where it is taking place. As in the Cornell study, if you combine hunting and sterilization, you will get a faster decline. 

Comment about another article reporting on this study from Anthony DeNicola

...  Please note that in Cornell’s case, surgical sterilization was used in conjunction with lethal methods to more rapidly reduce the population. The article mentions that birth rate and doe numbers declined. That is absolutely what we are trying to achieve. 
     With respect to increasing buck numbers, yes, there were additional bucks, but  once you move away from the tubal ligations and begin using ovariectomies, you will no longer see *any* estrus cycles attracting bucks. Also, please note that the camera surveys used were conducted over bait during a post-rut period and in a refuge surrounded by areas that are hunted. These details alone would concentrate bucks and inflate the estimate. It is likely that most of these males don’t reside year-round on campus.  The documented decline in females actually was successful. The "effectiveness" of the subsequent hunting harvest on campus was emphasized, but if they had not sterilized the females, that spring’s new fawns would have negated the 45% harvest.
     It is critical that we have every tool available to manage over abundant deer populations in developed areas and not prematurely dismiss a potentially viable technique.


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