In southern Oregon the porcupine population drastically declining. Why?

Question

Around Grants Pass Ore, Porcupines were once so plentiful that there was a bounty on them in the 1970's (50 cents a nose if I recall correctly) . Now most of the many local people I have asked have not seen a porcupine for 10-15 years. I am sure the bounty didn't kill them off, so what is happening. The only changes to their environment I know of is turkeys being introduced and a large influx of elk. So what gives? Have porcupines evolved camoflage, did some porcupine disease kill them, or... is something sinister going on.

Answer 1

They reintroduced Fishers(Martes pennanti) to reduce the high porcupine population, which was becoming devastating to the forests etc... Fishers are the only animal to consistently prey on porcupines. The result is that the porcupine population has gone down. I don't think anything sinister is going on at all... just a little more predation.

Excerpt... Because it is the only animal that regularly preys on porcupines, which often kill or damage small trees, the timber industry reintroduced the fisher to many parts of the U.S., including the southern Cascades of Oregon. The fisher kills porcupines with repeated bites to the face, devouring the porcupine via the quill-less underbelly. Where fisher reintroductions have been successful, porcupines have indeed declined in number. http://www.kswild.org/KSNews/pressreleases/fisher

Answer 2

Porcupine Population

Answer 3

Do you have documented evidence that they are declining? You should speak to a zoologist in your area that studies porcupines there.
I am sure one major change in your area since the 70's, which is an extremely common cause of organism declines worldwide, is habitat loss. Another too common cause is the introduction of non-native competitors. A third possibility is disease.
Porcupines have not "evolved camouflage" since the 70's, though they are secretive creatures that are usually nocturnal (active at night) or crepuscular (active at twilight). Most people these days have never seen a porcupine and would have to actively search a forested area to find one. You might notice that most people have ever only seen porcupines as roadkills. Roads are often built in a way that divides habitat, and many animals are killed attempting to cross the road to access that part of their habitat that is in their natural home range. It's a sad part of life but we as humans are greatly contributing to the decline in biodiversity and loss of species. If more people cared and more people were aware, perhaps we could change this trend.

Answer 4

Well, here is one theory:

"Pat Matthews, an Oregon Fish and Wildlife Department biologist in Enterprise, began noticing that porcupines were disappearing in the late 1980s after cougars began a dramatic population surge. An estimated 5,000 cougars now roam Oregon's high country, compared with roughly 200 in the 1950s, biologists say. "