Very interesting report!

On Aug 18, 2009, at 5:41 PM, Richard Fleming wrote:

> At dusk on May 8, 2008, my wife and I saw a mature river otter
> hauled out on the "turtle" log off the NW shore of Green Lake. It
> went into the water, caught a large carp, returning to the log.
> Seeing several people on shore watching, it went into the water and
> went elsewhere to eat the carp. The next morning I phone the zoo to
> see if they were missing an otter. They said no. WDFW had no
> reports of otter in Green Lake but thought it possible. There were
> other observations of an otter over several days, then it was gone.
> Earlier this spring the otter was reported again. About two weeks
> ago, there were several reliable observations of an otter. There are
> otters in Union Bay. The question at hand is how do they get to
> Green Lake for their visits? Up Ravenna Creek from Union Bay,
> thence the Green Lake drain to the lake? Thumbing a ride up Stone
> Way.? The mystery remains. Otters are good travelers, but one does
> not think of them moving along city streets.


Squinting very closely at the GAP distribution map for the River otter
the GAP distribution shows it potentially along the Cut and there is a
Green Lake/Woodland Park sized blob to the north of that. It has
connected water and trees, I guess.

<http://wdfw.wa.gov/wlm/gap/gapdata/mammals/gifs/luca.gif>

As they describe their minimum habitat block as 1 hectare (100m x
100m ... "about the size of Green Lake" they say on their home page)
then there is (was in 1997) potential habitat all along the Cut and
around Woodland Park.

How they're getting there is an interesting puzzle. Via a water way
like Ravenna/Piper Creek seems most likley but even then there is a
long dry walk down the grassy divide along Ravenna Blvd to get to
Green Lake. Have River Otters (or their sign) been observed in Ravenna/
Piper Creek? Or perhaps Thornton Creek?

Another possibility is via a linear connected "habitat" like Hwy 99 to
the Cut. The 99 corridor is the closest direct link to otter habitat.
That link is continuous from the Cut to the SW portion of the park:
about 1.3 mile from where 99 "touches down" north of the lake to the
SW corner of the Park. I can't believe they're very good climbers so
bouncing through back gardens like a raccoon doesn't seem likely.

If I was betting I'd think I'd prefer the creek route.

If they are staying at the lake then they need a holt. I can't all the
observers missing a holt at the edge of the lake but if one isn't
looking carefully one can miss it especially if it has an underwater
exit. And it doesn't need to be directly on the lake. Perhaps that
needs a closer look. Another possibility is the holt may be on Duck
Island away from humans? It seems like the only "natural" (unmanaged?)
area good enough for this.

So the question is are they visiting? Or are they staying? And how
many of them are there? I say them but is this a single individual?

Another consideration (for the adventurous) might be to consider
creating an artificial otter holt at Green Lake or along the Ravenna
Creek and Thornton Creek to encourage this species.

Plenty of ideas to follow up on for the Green Lake or Ravenna/Piper
Creek nature watcher.
--
Kevin Purcell
kevinpurcell at pobox.com