Crab Spider Tent

A crab spider and silk webbing at our family last weekend.

A few of us took a short trip out to our family prairie last weekend.  My daughter was back from college for the weekend and wanted to see what was happening in the prairie, so we did a little canoeing (tight circles in the small pond), hiking, and exploring.  Later, I found myself photographing dotted gayfeather seeds, and while I was looking for more of those plants, I stumbled upon a grass leaf that was bent funny with some kind of white silk holding it in that position.  I had actually walked past the grass leaf before my brain finally registered the fact that I should go back and examine it.

Looking more closely, I could see enough of the creature inside to identify it as a crab spider.  It had been raining quite a bit during the previous couple weeks, so my first thought was that the crab spider had made itself a little rain shelter.  (Crab spiders don’t make webs, but like all spiders, do make silk and use it for various purposes.).  However, my better guess was that it was a nest and that it might contain a bunch of spider eggs.  I photographed it for a few minutes, taking lots of photos, since the breeze was making it hard to keep the spider in focus.

A tiny spiderling, accidentally photographed.

Later, when I was looking through images at home, I was culling all the photos of the spider that weren’t in focus (dang that wind) when I happened to spot something that confirmed my guess.  Right above an unfocused crab spider face, a tiny spiderling appeared – just in one photo, not in any others.  Apparently, this was indeed a crab spider nest, and at least one egg had already hatched.  

The crab spider eventually shifted around and showed its face.

Crab spiders aren’t the only group of spiders that take care of their kids.  Frequent readers of this blog will, of course, remember a previous post of mine showing a mother wolf spider carrying her brood around on her body, and even if you don’t, you may have heard that wolf spiders lug both their egg sacs and newly hatched babies around with them.  Wolf spiders aren’t alone, though, and we’re still learning more about how well various spider species care for their young.  If you’re interested, you can read more in this nice blog post from Biome Ecology.  Otherwise, you can just join me in wishing this particular crab spider’s brood good luck as they disperse and try to find safe places to overwinter.

Photo of the Week – June 12, 2015

While I was doing some vegetation monitoring in a native hay meadow this morning, I found a bobolink nest.

Bobolink nest hiding in the grass - Platte River Prairies, Nebraska.
Bobolink nest hiding in the grass – Platte River Prairies, Nebraska.  Four bobolink eggs and one cowbird egg.

If you’re not familiar with grassland nesting birds, the idea of building a nest right on the ground might seem pretty silly and dangerous.  However, while a predator doesn’t have to fly or climb into a tree to get to the eggs, it still has to find them, and that can be pretty difficult when the nest is out in the middle of a large grassland.  To illustrate how well hidden the above nest was, here is a series of photos taken at various heights above it.

I took these photos with my phone.  This first one was taken about 2 feet  above the vegetation, which was itself about a foot and a half tall.  Can you see the nest?  (No you can't)
I took these photos with my phone. This first one was taken about 2 feet above the vegetation, which was itself about a foot and a half tall. Can you see the nest? (No you can’t.)

This photo was taken right at the height of the vegetation.  If you look closely, you can see the eggs below.
This photo was taken right at the height of the vegetation. If you look closely, you can see the eggs below.

A little closer.
A little closer.

ENPO150612_D003
This image makes the nest look very exposed, but only because I was holding the vegetation away from it to get a good photo.

The only reason I found the nest is that I crouched down in the vegetation a few feet from the nest to examine the plants in my plot frame.  About a minute later, the female bobolink fluttered out of the nest.  She must have waited anxiously as long as she could stand it, but my continued presence that close to the nest finally flushed her – allowing her to fly to safety but exposing the location of her nest.  Fortunately for her and her unborn chicks I took only photographs.  I wish her the best with her family, including one (so far) cowbird.

(For those of you who might not know the story of brown-headed cowbirds, they are brood parasites who drop their eggs in the nests of other bird species.  Those host birds then raise the cowbird young – often at the expense of their own.  This is a host-parasite relationship that has been going on for thousands of years in North American prairies.)

Isn’t it a little late to be nesting?

As you might remember, my Photo of the Week last week was an image of a fledgling meadowlark I’d found in mid-September.  At the time, I’d talked about how surprised I was to see such a young bird so late in the season.  Well, last Friday, Eliza Perry, one of our Hubbard Fellows, called me to say she’d just found a nest full of tiny birds – did I want to come take a look?  Of course I did.

American goldfinch chicks sit in a nest about three feet off the ground in a tall thistle (Cirsium altissimum) plant.  Platte River Prairies, Nebraska.
American goldfinch chicks sit in a nest about three feet off the ground in a tall thistle (Cirsium altissimum) plant. Platte River Prairies, Nebraska.

I’m pretty sure what Eliza found was an American goldfinch nest.  The bills and markings on the birds look right, and we spotted an adult goldfinch nearby.  However, the best supporting evidence was that the nest was located in a thistle plant (a native thistle species, by the way) and had thistle down in the nest cup.  There is a strong tie between American goldfinches and thistles.  Unlike most other bird species which feed their young on insects, goldfinches instead feed them regurgitated seeds – especially those of thistle plants.  In fact, they often delay their nesting until those thistle seeds have ripened.  Here is a link to photographer/naturalist Stan Tekiela’s post on this topic, if you’re interested in learning more about the topic.

These birds are even further behind the meadowlark in their development, and it’s already getting pretty cold overnight, so the nestlings’ chances for survival might seem slim.  Of course, the difference between the meadowlark and the goldfinches is that the goldfinches have adults around to help them.  Both have a challenging fall and winter ahead of them, but nothing others of their species haven’t dealt with countless times before, I guess.

A better view of the nest placement within the tall thistle plant.
A better view of the nest placement within the tall thistle plant.

Thanks to Anne Stine, our other Hubbard Fellow, who graciously helped hold equipment for me as we photographed the nest.  Because of the very bright early afternoon sun, I had Anne hold a diffuser near the nest to reduce the harshness of the sunlight while I held a small flash unit to better illuminate the birds.  We worked quickly and got out of the way so the parents could resume their feeding duties.

Photo of the Week – July 21, 2011

Not just another pretty face…

Dickcissel chicks (just a few days old) in restored prairie - The Nature Conservancy's Platte River Prairies, Nebraska.

Birds sure are pretty.  When they’re grown up!  At this young age, however, they are interesting looking, but it’d be hard to argue that they’re attractive.  I suppose you could say the same thing about human babies (if you could keep emotion out of it)…  they’re small, skinny, hairless, and wrinkled.  And yet we feed them and nurture them – and birds do the same!