Saturday, December 30, 2017

Urban wildlife interactions

Rock Paper Lizard posted yesterday about a mystery of how river otters made it into a pond about 2.5 km inland from the nearest natural body of water.  While river otters are much more adept at traversing land than their "sea" cousins (their versatility on land is one of their distinguishing traits), navigating the mostly paved overland route in Richmond would've been catastrophe.  Apparently, they're happy to muck around the exits of storm sewers, but it seems an especially bold maneuver to swim upstream of kilometres of concrete piping on the off chance there might be gold at the other end.

Having never seen river otters before, I decided to see if they were still around, today being the first blue-skied day in nearly a week.

One of the first creatures we saw upon arriving at Garden City Park was a bald eagle.  Not exactly rare, in Richmond, but unusual to be perched still, next to the pond for at least half an hour.

We meandered around the small pond...we figured if the otters were still around, there wasn't exactly a lot of hiding space, and they'd be easy enough to spot.  And before long, we did!

They'd swim around in the murk, diving periodically for perhaps 30 seconds at a time.  They'd swim on top of each other at times, clearly enjoying each other's company.

The otters made their way towards the other end of the pond, and we followed.  We then noticed the bald eagle diving down.

Initial thoughts were that it was diving for fish, but then we witnessed the target of it's attack.

The otters were on the bank.  Upon seeing the eagle, they retreated into the water, at least until the eagle returned to its perch.

And the reason for the interest from the eagle - fish! If I could talk to an otter (or more specifically, if it were willing to talk back), I'd like to learn how fishing is even possible in water whose visibility is about two inches.  In the summer, the pond is literally bubbling with fish, so with that density, I suppose that even bumping into them would be a reasonable technique.

We weren't the only ones who had noticed the eagle.  As is usually the case, gulls and crows will mob any type of raptor they see.

The eagle would only take so much of the intimidation before it set off.

Having been in the park for at least a week and a half, these otters have definitely gotten accustomed to people.  And with me watching for about a half hour, they became a bit more inquisitive.

Another distinguishing feature of river otters is that they'll swim on their front, vs sea otters typically floating on their backs.

In an urban setting, it's rare to see inter-species interactions, unless they are with the human or domesticated-animal variety.  I'm continually impressed at their resourcefulness, in spite of our efforts to control our environment.

The otters have been feasting on this small pond of fish for at least 10 days's probably the biggest windfall this family has ever seen...hopefully, they'll remember this in future years to make an annual return.


Doug Fraser said...

I wonder if their whiskers have some capability for detecting motion in the water? I know this is true of at least some seal whiskers - just considering your question about finding fish in very murky water.

Tim said...

Thanks for the comment, Doug. Web searches seem to confirm you're right.

Bella Sinclair said...

Cool sightings! I've ever only seen a bald eagle at the zoo and had to smile at how high pitched its cries were, despite its size. And I adore otters! I could watch them play for hours. Lucky you to have them freely interacting nearby.