Your municipal government usually has some budgetary expenses related to urban wildlife management. So why not just get rid of the need for this repeated cost by eradicating deer from within municipal boundaries?

Well, it’s not that simple. The BC Provincial Veterinarian explains that for culling to be effective, it must occur annually. When the population is reduced quickly through a substantial cull, competition for mates among deer is reduced, birth rates are higher and the population grows faster. Similarly, with fewer animals competing for food and territories, the body condition of remaining deer improves, also resulting in higher birth rates and hence quicker population growth.

This white-tailed deer photographed with 6 fawns is surprising. Our indigenous Columbia Black-tailed deer usually only have 1 or 2 fawns per year.

But in addition to the decrease in competition for mates and food resulting in fast population growth from the deer that remain, there’s another problem that can contribute to a quickly increasing deer population—immigration from areas outside the cull.

The sudden “void” in the population that is created by a cull provides opportunities for deer in adjacent regions to immigrate into the newly created competition-free landscape of abundant food. And so, the population once again grows quickly.

So, for culling to be an effective management tool, it would need to be done annually, and it’s not cheap. The CRD spent $272,000 in the 2014/15 fiscal year, with $50,000 spent on the 2015 cull in Oak Bay alone—for the cull of only 11 deer. It’s going to get very costly, very quickly, if a significant number of deer would need to be culled annually.

As an alternative, we’re assessing whether birth control (that’s right, birth control—known as immunocontraception or IC) may be a more cost-effective alternative. Getting those deer on birth control will decrease a population gradually, avoiding the fast population growth rates that a cull can produce. For the capture and collaring of the deer in this study, to date, the cost of the vet’s time on this project has been only $6,000 for over 2.5 times the number of deer handled in the 2015 cull. So for the same amount spent in 2015, we’ll be able to IC a very large proportion of the deer population—so we expect this to be much more effective than that cull was. As a bonus, we expect that IC won’t need to be repeated annually—we’re still trying to figure out how often it will need to be administered, but projected cost savings—to achieve the same goals as a cull, without the problems with rebound population growth—are significant.

This could be a win-win for all of us.

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