WHAT’S THAT BIRD DOING? This time it was a female goldfinch who elicited the question. She seemed to be pecking at the windowsill (above), but it wasn’t the sill, exactly, that caught her attention. It was a big spider web attached to it. But why?
American goldfinches breed later in the summer than most songbirds, says Cornell Lab of Ornithology’s All About Birds, timing their mating to coincide with peak thistle-seed production. The thistle figures into the equation in two ways: They feed the seed to their young, after they use some of the downy fiber from the seedheads to line their nest.
And what do they use to hold the nest together? Sticky spider-web silk, the preferred Super Glue of other bird species, too, including various hummingbirds, vireos, warblers, bushtits and even the handsome indigo bunting. Apparently the stuff is so precious, at least one species–the cerulean warbler—gathers and reuses it if a second nest is needed after a mishap with the first, says Cornell.
The rufous hummingbird, for example, builds what my friends at BirdNote call a “marvelous nest,” connected with spider silk and covered, for camouflage, with lichen. It looks like this. (The hummingbird above got a bonus bug in its bit of web; photo by Gregg Thompson.)
My goldfinch friend (with a glob of spider silk on her beak, above) didn’t seem interested in bonuses, but webs are often laden with insects—the perfect snack for a busy female bird in search of adhesive, before she continues on her calorie-consuming building project. It’s like she made a trip to the grocery and hardware stores all in one.
what’s that other bird doing?
I’VE ASKED the question before: What’s that bird doing?
- When blue jays pecked off the paint on my porch one winter, I wondered why.
- I asked what’s going on when small birds “mob” much bigger ones, chasing them boldly in the sky?
- Is the cowbird a “bad bird” because it uses other species’ nests, I wanted to know?
- Is that black bird a crow, or a raven?
- What’s all the drumming about, with woodpeckers?
And on and on. Birds make me endlessly curious.
Just the other day, I watched separate performances by the American redstart pair who show themselves regularly by my patio, usually doing a sort of fan-dance (as in the video above) with much spreading of tail feathers and wings. Just what is all that drama about, I asked the showoffs through the open window? No answer—so I asked Cornell Lab of Ornithology’s website instead.
Redstarts, it says, “rapidly spread their cocked tails, exposing the orange or yellow in a quick flash, which often startles insect prey into flushing, whereupon the redstart darts after it, attempting to catch it in the air.” Whatever it’s about, I do love the fan dance, and this flashy little warbler in general.
My friends at BirdNote, the Seattle-based public radio show, had another layer of “aha” on the redstart’s tail, genetically speaking. Listen to this Birdnote segment to find out what the DNA of a male’s tail feathers can reveal. Another answer to a much trickier question, that one.
- All my Q&A interviews with BirdNote are gathered at this link.
I knew the hummingbird used spider silk but had no idea my favorite American goldfinches did also. And many more too! Silly me to have never thought about that. I love the things one sees with a garden at hand!
I always tell people not to spray their spiders away! Being close to the St. Lawrence River or any water, seems to up the spider count somehow and a lot of people that live close to the water spray for spiders. I know hummingbirds like those spider webs, a lot of birds eat spiders and that certain bees/wasps use spiders as hosts for their young so I learn to live with the spiders. Now I know that goldfinch also use spider webs! I often see house sparrows picking through spider webs for the bugs, too, or “hunting” the eaves of the house for spiders. It’s a wonder there are so many spiders with all those hungry and crafty birds. A spider seems to take up residence in my rearview mirror each summer – it’s a handy hiding place that also gets around.
SO grateful you wrote this! I’ve been seeing lots of sparrows and other small birds flying off the sides of my house and the gutters, and i’ve been baffled, and a little concerned! I didn’t realize that they’re feasting on the bugs ensnared in the zillions of spider webs!
Interesting, isn’t it, Siri. Nature cleans its plate, not a scrap left uneaten or unused for some purpose or other!
The bird information is good to know, but my favorite part of the post was seeing your heart stones beneath the window. So many treasures in nature.
Yes, indeed, Laurie. So many!
thanks Margaret!
If goldfinches time their mating with thistle availability, are we confusing them by providing Niger seed for them in our feeders?
They wait for the thistle down to line the nests, and also use the seed…whenever they can find it (even on left-behind seedheads later, once that didn’t get picked-over sooner). So I figure that they don’t confuse winter scavenging for food with breeding time.
So fun to read. I would never disturb a hummer nest, but one fell out of a tree and dropped on our little road. Fearful that it would get run over, I took it home and have been examining it with a magnifying glass. It is truly a wonder of construction by such tiny engineers and quite a collection of fibers. It will have a place of honor on the sunroom table just the other side of the window that now displays the feeders and the endless hours of activity. Being blessed with hummers is a wonderful thing.
Lucky you, Lorie, to get to take a close look like that. Lots of hummingbirds here but I almost never spot the nests.
your curiosity is very funny and fascinating your explanation :)
Thanks, Ileana. I have been like this since childhood: Asking “Why, why, why?” all the time.
I have a white Persian cat who likes to lounge in my patio. My outdoor mat was covered with her soft fur, and it was really hard to get it off so I gave up. Early this summer I noticed small finches picking at it when the cat wasn’t around……Lo and behold it is now completely clean! I’m sure they used her soft silky fur to line their nests!
My dog has lovely long black and tan fur. Whenever I brush her, I fill up a suet cage with her fur and put it out for the birds, usually in the spring when my pup is shedding. Tickles me to see the little birds with tufts of my dog’s fur in their beaks flying off to line their nests. So cute!!
That is SO lovely, Marie! And hilarious, too. Thanks for sharing.
I love spiders and keep telling everyone how good they are about keeping the insect population down. I do have to keep an eye out at my beehive becaue some enterprising spider will often set up camp and get some of my bees. That is where I draw the line in leaving them alone. I clean their web out a couple of times and then they move onto to a more friendly spot.
I would love the book giveaway!
Yes, you are so right. Please, please, please don’t spray your bugs. The birds eat the sprayed bugs and also feed them to their young and the spray does harm the the birds. If we let nature work properly, birds work better than spray and the natural world is less harmfully affected.
Precisely!
I just watched a very small bird pulling spiderwebs off of my backyard fence. At first I thought it was stuck to its feet but then I saw it fly off with it to one of the trees so I googled it and that’s how I landed on this website. You learn new things every day I guess.