There are many more deer on Mayne Island now than in previous centuries. The evidence for that statement is available for anyone to see: most native plants on Mayne Island are decreasing in abundance as a result of deer browse. Have you seen sword fern with its tips chewed off? Salal slowly dying as deer eat the new growth and the old leaves fall naturally, never to be replenished? Sword fern and salal are low on the list of plants deer prefer to eat, so when you see them being eaten, it means all the deer’s preferred foods are already gone. What we don’t see is even more important than what we do see: species such as snowberry, thimbleberry, and western red huckleberry that should be common in our forests, but are found only where the deer cannot reach them. Camas, chocolate lily, fawn lily, and Menzies’ larkspur—once common wildflowers— are now rare.

Heavy browse on sword fern is an indication of deer overpopulation.

The effects of deer are slow to be seen for some species such as the arbutus and Garry oak, which are long lived, and when mature are above the reach of the deer. However, new seedlings that begin to grow are sought out by the deer and eaten. The deer are so many, and so effective at finding their favorite foods, that for many species this means the only survivors of the next generation will be found behind fences or on the side of cliffs.

Arbutus seedlings are only found within fenced areas.

This imbalance is not just bad for plants. Plants are the building blocks of the ecosystem. They capture energy from the sun, and provide structural habitat for birds and insects. When you lose the plants, you also lose the insects, birds, bats, and other animals. Ground nesting songbirds rely on undergrowth for nesting sites, and studies have shown there are fewer songbirds on islands with lots of deer. Too many deer is also bad for the deer themselves, and for humans who live within this unbalanced system. As food becomes scarce, especially in dry summers and cold winters, the deer become more aggressive in their search for food, knocking over fences and eating less edible foods. As the deer are forced to eat less edible plants, their health can suffer. Unnaturally dense wildlife populations can also favour the spread of disease, some of which can pose risks to human health.

Wildflowers growing on a small islet near Mayne Island with less deer browse.

The reason for the increase in black tail deer is a loss of natural predators such as cougars and wolves that lived on the island up until the late 1800s. Since then the black tail deer population has grown far beyond its historic size. In addition, a second species of deer, fallow deer, was introduced to Mayne Island in the 1990s. The fallow deer population has increased dramatically from a few animals to a currently unknown number. Combined, the deer are having a devastating impact on our local ecosystem. Deer overpopulation on Mayne Island is a result of human actions, since we are the ones who are responsible for the loss of predators that once kept the black tail deer in balance, and who introduced the non-native fallow deer.

Fallow deer exhibit a broad range of colouration.

We at the Conservancy are often asked by hunters with BC Hunting Licenses where they can hunt on Mayne Island. Please note the following: There is no public land on Mayne Island where hunting is allowed. No Crown Land, no BC Parks. Hunting can only occur on privately owned lands with the prior permission of the land owner. In addition, there are restrictions and special requirements for hunting in the Gulf Islands such as a requirement for liability insurance, and purchase of a Special Gulf Islands Hunting License. See the Province of BC’s Hunting Regulations for full details. Please note the Mayne Island Conservancy does not offer any services to connect hunters with local land owners.

Suggested Reading

https://ibis.geog.ubc.ca/biodiversity/InfluencesonBiodiversity–Deer.html

https://mayneconservancy.ca/wp-content/uploads/2019/11/Mayne-Island-Deer-Report-2013.pdf


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