Category Archives: Seasons

Field Notes: Jewel Worlds in Teaser Season

Every year in late January or early February, we seem to get a week or so of lovely weather: sunny skies, temperatures in the 50’s that lure us out into the forest or onto the beach. And every year I succumb to the hope that spring is really on its way early this year, that the abiding gray will give way to blue, that the scent of moist air will get its floral infusion in February instead of April. Continue reading

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Arachnitecture: Season of Spiders

Oscar has once again made her summer home in a corner of my bathroom.[1]

Oscar in our bathroom. Discarded debris from his meals is below his web.

Oscar in our bathroom.
Discarded debris from her meals is below her web.

The season of spiders began here a couple of months ago, with the appearance of the first obvious webs in dark corners. Then I began having to dodge webs strung across my favorite forest paths. Now they’re all over, indoors and out, helping their owners make a living extracting bugs from their territories.

My grandmother called all spiders “Oscar” and allocated them an honored status in her home on Dauphin Island, Alabama. Oscars ate the mosquitoes and gnats that plagued us kids on our spring-break visits to her dockside ranch house. So although some of my best friends are arachnophobes, I’ve always enjoyed having spiders around.

This Oscar’s dining room is a tangle-web, an extravagantly three-dimensional array of strands that’s particularly difficult for the unfortunate prey to find its way out of. Maybe that explains why Oscar’s so healthily chubby. (My cleaning habits have nothing—nothing, I sayto do with that.)

Some of my forest spider friends, the Cross Spiders, build those familiar iridescent orb webs that catch the light so beautifully.

Cross spider's orb web Lincoln Park, West Seattle

Cross spider’s orb web
Lincoln Park, West Seattle

By autumn, they’ll drape the forest as spiders grow larger and need more prey.

Forest air filled with webs; look closely to see them at all levels

Forest air filled with webs; look closely to see them at all levels.
Click on the photo to enlarge.

Here’s the exquisite builder of those shimmering dreamcatchers:

Cross Spider Lincoln Park, West Seattle

Cross Spider
Lincoln Park, West Seattle

But my current favorite is the Sierra Dome Spider, who builds this wonderful Buckminster-Fullerish type of web, about four to seven feet off the ground, specially designed to capture bugs rising from the vegetation below: an angel’s tiara accidentally left behind in the forest.

Sierra Dome Spider's web Lincoln Park, West Seattle

Sierra Dome Spider’s web
Lincoln Park, West Seattle

Such a stunning home also draws romance.[2] Male Sierra Dome Spiders, dreaming of love, are attracted to females with their striking dome nests—and see how beautiful she is! That lovely orange thorax, those delightfully translucent blue legs!

Sierra Dome Spider

Sierra Dome Spider

But after their romantic encounter, he’ll then destroy her nest by rolling all those carefully placed threads into a ball, to keep other males from sniffing around. She has to rebuild the whole thing, strand by strand, in order to feed herself.[3]

Tangle-webs, orb webs, dome webs: three different architectures, each tailored for what its builder needs. But there are a few essential functions they all have to fulfill. They have to be able to trap prey and hold it long enough for the spider to get there. They have to hold the weight of the spider. They have to be able to stay basically intact under the influence of a struggling bug, and as the spider wraps and removes her prey. And they have to be strong enough to withstand wind and rain.

Cross Spider with wrapped prey

Cross Spider with wrapped prey

Look at her web after she’s trapped and removed prey. It’s full of gaps where strands have been broken.

Cross Spider's orb web showing prey damage

Cross Spider’s orb web showing prey damage

Yet removing one thread, or even many, doesn’t cause the whole thing to collapse.[4] Spiders have developed the ability to produce different kinds of silks to serve the various functions of different parts of their web.

For instance, consider the strands that are sticky to capture bugs. Most solid materials break more easily if there’s already a surface rupture. To keep such initial cracks from developing, spiders coat their capture threads with a watery coat that lets those strands absorb vibrations more easily, giving them more elasticity. That means they can hold the prey longer, giving the spider time to get there.

Spiders’ strands also have a strange but really useful three-part response to being tugged. The whole web of threads shimmies with the prey’s wiggling (alerting the spider to its presence), holding together, but as the bug’s struggling puts more stress on the threads near it, they suddenly get very pliant, taking the stress off of more distant threads—which can then continue to hold up the web. Finally, under lots of stress, the buggy silk once again gets stiff, meaning it will break at the stress point, leaving the rest of the web intact.

On the other hand, when wind puts equal stress on the whole web (as opposed to a bug stressing mainly one thread), the whole thing stays strong. Amazingly strong, in fact: your neighborhood spider’s web can stand up to hurricane-force winds.

These architectural marvels are everywhere during this season of spiders. Even though “you’re never more than three feet from a spider” is probably one of those spider myths, there’s probably one closer than you think.[5] Thank Oscar for his excellent work next time you see her.

Sierra Dome Spider, waiting

Sierra Dome Spider, waiting



[1] I have left in embarrassing details about the state of our bathroom to show how helpful he’s being in cleaning it up for us. [back]

[2]  Apparently it works for some humans too; a realtor friend once told me back in my single days that if I were to succeed in buying that adorable quirky little cottage tucked into a Seattle greenbelt, I wouldn’t remain single for long. Although I did not buy that particular quirky cottage, I did later buy another. I did not remain single for long. [back]

[3] My companion has not yet destroyed my home, although he is planning some extensive remodeling. [back]

[4] Unlike a major bridge in my state. [back]

[5] Sorry, arachnophobe friends. [back]

Blockwatch

Taking a break from working on a writing deadline, I loaded up my binoculars and camera and headed down my street toward the park. I didn’t make it farther than the end of the block.

Atop the light pole on the corner was a Northern Flicker, calling loudly to an unseen companion (who joined him later).

Northern Flicker with mate

Northern Flicker with mate

Then he made his way vertically down the pole, investigating various holes tiny and large.

Northern Flicker examining hole

Northern Flicker examining hole

Northern Flicker examining second hole

Northern Flicker exploring hole #3

Northern Flicker exploring hole #3

Let’s look at that last photo a little more closely:

Northern Flicker extends tongue into cavity

Northern Flicker extends tongue into cavity

Woodpecker tongues are really amazing. The structure supporting them wraps all the way around their heads, in some cases looping around their eyes.

https://i0.wp.com/www.sloshtheory.com/Anatomy/files/collage_lb_image_page4_0_1.png

Woodpecker bone and tongue structure. Click on link for source.

This gives most woodpeckers lots of tongue with which to explore tree cavities—and that means they have to spend less energy on excavation. Then when they encounter delicious bugs, their elegant barbed tongue is sticky enough to grab the bug and bring it back to where the woodpecker can enjoy his meal.

Tongue of Hairy Woodpecker. From "The Woodpeckers," by Fannie Hardy Eckstorm (1901)

Tongue of Hairy Woodpecker. From “The Woodpeckers,” by Fannie Hardy Eckstorm (1901)

But that’s not all we can learn by observing what’s happening on our block! Let’s go back to the flicker’s exploration of the second hole. Did you notice anyone else?

Black-capped Chickadees monitoring flicker

Black-capped Chickadees monitoring flicker

These two Black-capped Chickadees flew in together, at first scolding the flicker and then remaining silent as they watched him poke around in their prospective nest holes. They waited until he left, then went back in — maybe to assess what damage he might have done with that huge beak and strange-looking tongue?

Black-capped Chickadee checking out hole post-flicker

Black-capped Chickadee checks out possible nest hole after visit by flicker

Black-capped Chickadee explores possible nest hole after visit by flicker

Black-capped Chickadee explores second possible nest hole after visit by flicker

I haven’t seen the chickadees at these holes for the past couple of days; maybe they’ve decided to search for nest cavities on a less popular tree trunk.

*   *   *

This afternoon, lured by irresistible sunshine during this extraordinarily wet April, I headed back out towards the forest. Nope.

I’d heard frantic robin cheeping, so I figured a hawk was somewhere nearby. Another drama in our little corner of the city? Yes – but with different players. As I walked out the door, I turned away from the forest, toward the robin calls…just in time to see a crow fly off with a lovely blue egg in its beak.

Hope and tragedy, all in a few short days on one short city block.

What’s happening on your street?

P.S. – There’s a sequel to this story! Check the next post, “Blockwatch Success,” to see what happened.

Male American Robin

Male American Robin