
Other than deer and elk, there are many other species that call the refuge home.
“The deer are the main large animal,” Clark said, “and elk, which we expect there always will be; they are native wildlife too.
"But in terms of furry animals, there are large numbers of nutria, an exotic species that we could live without; there are also a lot of beaver and mink, and river otters are very common.”
A lot of amphibians and reptiles call the refuge home as well, including painted turtles, snakes and salamanders, he said.
There are areas of secure habitat for the deer.
“Generally speaking, we interpret that secure habitat is habitat that is probably in public ownership or at least dedicated to conservation,” Clark said.
Aside from the refuge, these areas include Crims Island near Clatskanie, Fisher Island at Longview, and Tenasillahe Island, the large island in the river across from the refuge mainland. Puget Island is not considered a secure habitat because of the many private ownerships.
The recovery plan for the deer hasn’t been updated in some time but is still in effect.
“The deer can be considered ‘recovered’, which means removed from the Endangered Species List, if we can maintain a population of a minimum of 400 individuals, distributed in at least three sub populations on secure habitat,” Clark said.
A sub-population refers to each of the secure habitats. They must be of a certain size. Five or 10 deer in a sub-population isn’t sustainable.
“It has to be 50 at an absolute minimum,” he said. “You can’t just throw 50 deer out there and say, ‘well, now we have 50’, you have to see if they are going to survive, propagate and maintain. It takes a few years to be able to make that judgment.”
At the end of the month, Clark said, USDFW will begin aerial surveys to track populations. Experts will use the same high tech infra-red cameras the military and police use when tracking a suspect. The cameras detect heat on the ground and will make counting the large animal populations a lot easier than being at ground level.
Over the past 10 years, estimates of deer populations have declined based on helicopter surveys.
From 1996 to 2007, the refuge population declined from 100 to 60. The 2006 survey was affected by a severe flood in early November, according to refuge statistics, and peaked at 125 in 2002.
On Tenasillahe Island the population declined from 150 in 1997 to 85 in 2006.
On Puget Island, the numbers declined from over 200 in 1996 to 125 in 2006.
In Westport, Oregon, numbers declined from over 200 to 100 in 1996.