Bounding about a bay

A few weeks ago, a friend convinced me that we should go to the beach.  As I hadn't done that in a while, and low tide was conveniently in the afternoon, we decided to head to Boundary Bay.

The low tide measured about 1 metre, which in the tidal flats of Boundary Bay means about a kilometre to walk out from the beach out to the water's edge.  That meant plenty of tidal pools to explore.

Eel grass provided habitat for many animals, including nudibranchs (the first time I've seen them in tide pools)

Anemone (1cm wide)

A mass of eggs of something

As we made our way out to the water's edge, we saw more and more sand dollars.  Most of you have probably seen them either at the beach or a souvenir shop - a white, chalky disk.

A sand dollar test on the North Coast Trail

This is merely the "test", or skeleton, of a sand dollar.  Sand dollars are relatives of sea urchins, and like urchins, are equipped with spines when alive.  By the time most of them wash up on the shores of beaches, the abrasive sand scrubs off most of the spines.

Live sand dollars will live where the water is fresher, in the lower portion of the intertidal zone.  It was here that we found living sand dollars.

With the spines, one can easily see the resemblance to sea urchins.  However, the spines are tiny and much more densely packed than that of an urchin, and they are used more for digging than protection.  With a coordination similar to that of a sea star (sea stars, sea urchins, and sand dollars  are all in the echinoderms phylum), the sand dollar coordinates its spines and tube feet to position itself nearly vertically in the sand, half buried. It catches small particles of food as it floats by, and moves them towards its central mouth.

Other critters were much more difficult to observe without actually catching them.

Shrimp

As we walked through the tide pools in our bare feet, we could easily see the fish darting away from us.  With their camouflage, they became invisible as soon as they stopped moving.  However, we took advantage of their escape behaviour to capture them.  Some would squirm into the shade of our feet each time we took a step.  After we got over our delight of them tickling our feet, we could trap them against our feet and our cupped hands.

Only a flounder as small my fingernail could stick onto a vertical surface

The sculpins were likely tide-pool sculpins, a common species that grows to a maximum size of a couple of inches.  As for the flounders, I knew that they start off life free-swimming in the plankton, whose eyes migrate to the same side of their head as they settle on a life on the sea floor.  I didn't know how large they are when this eye migration happens.  Internet research says that in one species, it migrates at around 1/2 of an inch in size, which matches the size of this flounder, so it's possible this is really a baby flounder and not an adult (I don't know of flounders whose adult sizes are this small).

The largest sculpin we caught was maybe an inch long

My friends and I quite thoroughly enjoyed our day exploring at the beach.  The abundance of life in what one might think is a barren mud flat will definitely bring us back.

Charlotte's Web

One of the first stories of wildlife I remember reading was Charlotte's Web, by EB White.  The unlikely friendship of a pig and a spider reassures the young reader that even when one thinks one is alone in the world, one really isn't.

Spoiler alert for those who haven't read the book, but enjoy reading books for youth and might one day read this one:

The story finishes with Wilbur, the pig, finding Charlotte, the spider, missing, and astonished that her offspring fly off into the wind with nary a concern for their future.  With glee, they catch the wind with their threads, disappearing into the atmosphere.

Araneus Diadematus is Charlotte.  She is the most abundant orb weaver in Canada who can claim responsibility for spiral (orb) webs larger than 30 cm.

Each day of their lives, as long as the weather is dry, they spend 30-60 minutes building a web in the dawn hours.  Typically, they'll rebuild in the same location, but they will change locations to suit food abundance and personal safety.  As they reach maturity, their mobility decreases (they are poor walkers) so they spend the final months of their lives in the same home, under a man-made ledge or a cluster of leaves in a hedge.

In the dark nights of fall, the now heavy females then make one final pilgrimage to find a nesting spot for their eggs.

October, 2012

She is gravid - her abdomen is full of eggs.  After laying her eggs, her abdomen will shrink to about a fifth the size - the size of her cephalothorax (she will look similar to a male).  She will guard her eggs, but ceasing to build any webs (a good nest site is not necessarily a good web site), will eventually starve and die.

On a spring day, about 6 months later (as was the case for these), the warmth and dryness will trigger her eggs to hatch.  Thousands of tiny yellow bodies will cluster together for a few days while they get a bearing on life.  Then one by one, they will crawl to a relatively high point where they will release a thread of silk, allowing it to be caught by the wind, and be ballooned off towards new lands.

Each one, with legs outspread, could fit inside the 'o' on your screen.

At least six eyes are visible.

Ballooning spiderlngs have been witnessed, kilometres-high in the sky.  They are equivalent to atmospheric plankton, going where their currents take them.  This effective dispersal strategy typically makes them the first arrivals to any newly terra-formed volcanic island, though they may need to wait a while for food to arrive.

As soon as they can walk, they know how to spin a web. Their instincts lead them to build their first web with a technique identical to the last web they will build.  There are no practice webs, no "I was feeling lazy so this is the best I could do" webs, no bragging about "this is my best web, let me Facebook this".  No emotional excuses for doing what they need to do to survive, to propagate their species.  They build webs, simply because they are spiders.

Bald on the beach

On the way back home from a grocery run one afternoon, we saw a large convocation of eagles on the beachward side of the roadway.  We pulled over, and witnessed about 30 bald eagles in the midst of a frantic feast (though wild animals do tend to always dine in degrees of franticness).

Taking off with the bounty

With nearly a dozen eagles permanently guarding what remained of the food, another dozen or so sitting on nearby perches, and another couple dozen or so in the air flying in, grabbing bits of food, and flying off, and another few dozen or so in trees savouring their meal, there were perhaps 60 eagles in the vicinity.

Latecomers

It was only after about 10 minutes of observation that it became clear to me what they were eating - discarded salmon heads and backbones.  A fisherman had dumped them on the beach, to the enthusiastic glee of the many eagles.

Giving chase - entering the mad foray surrounding the pile of salmon carcasses might require boldness only the tenacious youngsters or the more senior adults possess, but intimidating another eagle to drop its food is something anyone can do. One needs to consider the ocean-bound scavengers, however, such as the seal in the foreground.

Onlookers

Fanny Bay - not just known for their oysters

One of my sources for information about nature on the island is Island Nature .  It is because of that site that I first heard of the herring spawn in Comox, driving my desire to visit the beaches there.  The blog also informed me of the sea lions stationed at a floating wooden structure at Fanny Bay (location of the famed Fanny Bay oyster farms), which was on our way up to Comox.

I've seen sea lions in the wild, but never this close, and never this many.  They are here for the herring.  From the parking lot we could already hear their loud barks.

"I hear barking, but they don't look like dogs"

Rafts of lions

From our pier, we were probably only 10 metres away from the boisterous pinnipeds.  We didn't think we could get any closer.  But we did.  A dive boat had just dropped off its divers, and the driver of the boat asked if we'd like a short boat ride to the raft of sea lions. Who would say 'no'?

Contentment

barking contest

The type who can sleep despite the ruckus

I think we all know who the bully is here

Sea lions are one of the creatures who are quite comfortable with humans, making them easily viewable.  With full bellies, and about four times heavier than any of us, they did not seem to care as we circled them in our boat.  They shouted barks in our general direction, but were generally more concerned with preserving their prime resting spots, making for a wonderful viewing opportunity.