How to Engineer a Bird’s Nest


One of the perks of my job is that I get to have fun creating new science-based, nature-related activities for kids. This winter break I wanted to create an engineering-based activity for creating a realistic-looking bird’s nest using natural and/or biodegradable materials. It sounds easier than it actually is — even birds who do it by instinct spend many hours or even days collecting materials and creating their nest, and what seems to come naturally to them can be quite the engineering challenge for humans. It certainly isn’t a new idea for a kids’ activity, either, but it’s one that often leads to less than satisfying results. I also knew that I didn’t want this to be just an arts-and-crafts activity with chenille stems and other wasteful materials, and I wanted youth to be able to present their own ideas and find solutions. At the same time, I needed the core activity to be sound enough for success.

Different bird species use different techniques and materials to build their nests. Birds that create a “traditional” nest will typically select a sound structure that will support and even provide a little basic framework for their nest, then they gather twigs and other materials for a little trial-and-error placement to get the nest going. They then keep building it up, weaving materials and using mud and saliva and other means to prevent the nest from falling apart. Other birds mix mud and saliva as a cement for shaping an earthen nest, some do complicated weaving patterns with grasses, some incorporate spider webs and even snake skins, and some bypass the issue entirely by simply cushioning an available cavity in a tree or man-made structure. Birds are amazing engineers! For this particular task, I wanted to focus on the classic nest look with twigs and grasses.

makingbirdsneste01-03-2016How do you turn this activity in a youth-driven engineering challenge? One option is to have them gather (or you provide) a bunch of natural materials and challenge them to create a basic nest that will hold a set number of like objects, such as 3-4 marbles. They can do so individually or as partners, and it’s a lot of fun. It can also be done in a single lesson or in about a 1-hour time frame.

But to fully create a realistic-looking nest, start by helping kids identify the tasks in front of them. Show pictures and videos of birds building nests and lead a discussion about some of the challenges birds have to deal with to make a sound nest. You might even let the kids work with the materials for a while to consider some of the difficulties of the task ahead. Guide them to think about such questions as the following:

  • Will the nest structure require framework?
  • How do you keep the nest from falling apart? How would birds do it? (mud and saliva, spider webs, weaving grasses, etc.) For our nests, what could we use instead of mud?
  • What kinds of materials would work best for the main nest? For example, what length and thickness of twigs and/or grasses might be best? Should items be flexible or sturdy?
  • How do you keep the inner shape of the nest relatively round?
  • Should you add a lining for the eggs and baby birds? What might birds use? (soft plant fibers, dog fur, downy feathers, leaves, etc.)
  • Is there anything unique about the nest that you’d like to build? Would you add a roof of sorts or create more of a cavity style?

Once kids have identified questions and pondered the answers, help them figure out their basic plan. If they have a good idea they want to try, let them go for it. You can also show them a sample of dried twine pieces glued together and see whether they think it might be a technique they’d like to use. Let them be a part of figuring this out as much as possible. You might also wish to explain that twine is made from natural plant materials and is biodegradable, and that white school glue is non-toxic.

makingbirdsnesta01-03-2016The following shows how to shape the activity using the glue and twine technique. Modify it according to kids’ ideas. Have kids make suggestions for what objects could be used to create a mold for the nest (such as a bowl). Have them also consider how to protect the bowl or other object from the glue (perhaps plastic wrap). Guide kids to see why shorter pieces of twine are potentially safer than really long ones, if the final nest might get placed permanently outside (shorter pieces are safer for wildlife to keep them from getting long twine wrapped around a foot or limb). Have the kids cut the twine into pieces 5-6 inches long.


Let kids measure and mix the glue, water, and corn starch to make a sticky paste. For a single nest, I used approximately 1/4 cup water, 1/2 cup corn starch, and about 1/2 cup white school glue or tacky glue (non-toxic). The mixture is fairly thick but fluid enough to allow easy coating of the twine pieces.


Working with a few pieces at time, use a spoon or fork to help coat the twine.


If you haven’t already, be sure to protect your bowl by covering the outside in plastic wrap, taping in place as needed (this will also allow for easy removal of the final structure). Have kids take a piece of coated twine, squeezing off the excess glue mixture. Then let them figure out the way they want to place the sticky twine on the bowl, keeping in mind their engineering requirements as they add more pieces. But you might suggest that they imagine what might happen to the nest if the twine were to get wet in the rain. How easily might it fall apart if the glue softens? Should they overlap and weave together the twine pieces (I did). Do they want to make knots? Open spaces are fine at this point.

I’ll admit that this part is messy, so hopefully you’ve put down some newspaper or cardboard or some other material to protect your table. Encourage kids to not smear glue on their clothes or on furniture during the activity, and be ready to get them to sink the moment they are done.

Let the nest frame dry for a couple of days. This is a fine time to let kids collect twigs, leaves, grasses, and other natural materials for their nest. When ready to work with the dried twine frame, help kids carefully remove their structure from the bowl and plastic wrap.


Then the fun begins — time to weave the natural materials through the nest frame! What size twigs seem to best, or can they vary? What materials are flexible enough to help weave through back and forth to “lock” other materials in place? At what point should you switch to softer lining materials? How can you keep the open bowl shape for the nest? Let kids do this with tweezers or forceps if they want to imagine they are birds at work!

makingbirdsnesti01-03-2016Have kids keep adding material until holes and gaps are filled and nothing slips out as they move the nest around. Encourage them to rotate the nest often and triple-check for gaps. To add to the challenge, you could have kids test the strength and stability of the nest by temporarily adding rocks, marbles, or other weighted items, by using a fan to blow on the nest, by giving a gentle shake to the nest, etc. Let kids make adjustments to their nest accordingly. At the end, discuss again how birds in nature make nests and why it’s important for the nest to be sound in structure. Why might different species have different nest-building methods?makingbirdsnesth01-03-2016

I used both dried and fresh grasses to help secure many of thin twigs and flexible stems I gathered. Within a couple of days, the greenery was already turning brown, though I didn’t take any new pictures.

Could you or should you put your nest outside? I think if you feel it’s fairly solidly built, then it’s fine, as long as you also put it in a place where it won’t fall to the ground in wind. I would expect that any bird parents actually interested in using the nest would add their own material to enhance the nest and check it for stability. But if it’s fairly loose and has some gaps, then just use it as decoration for home. If doing so, how might you create some eggs or a small bird to add to the nest?

This activity can be adapted for kids of any age, but I think that kids 3rd grade and up will be able to most of the work on their own. Grown-ups can have fun making a nest, too — you just have to be a kid at heart!

Spiny Oak Slug Caterpillar — Look But Don’t Touch!

spinyoakslugcaterpillarb06-04-15While working on the front yard, we ran across this odd creature at the base of a rogue Hackberry seedling. It seemed fairly obvious that it was some sort of caterpillar, until we saw it move. Then it was like… WHOA. Instead of seeing it move along like a regular caterpillar with its legs and prolegs (though apparently a caterpillar actually moves by its gut), what was visible on this caterpillar was a wavelike motion as it traveled. The closest creature I could compare it to, barring that of something from the ocean, was a slug. Turns out that I was right on the money… its common name is actually “slug caterpillar,” or in this case a Spiny Oak Slug Caterpillar. I’m fairly confident about the ID, except that there seems to be a wide variation in color for these little guys. If I were to guess, their coloration might have something to do with what actually tree they are feeding on, or what instar they might be in, but again, just a guess.

To share this amazing undulating movement, we took a video, seen below. We used a macro to get in close to see the waves, hence the occasional moments when the caterpillar goes out of focus. But the gist of the movement is there.

Since this is the first time I’ve ever run across this type of caterpillar, I don’t have a lot of details about it. It will turn into a moth, and my instincts NOT to touch it were spot on. Like other slug caterpillars in the family, it has a painful sting, though this one is milder than some of its cousins. Also, its thoracic legs are reduced, contributing to those rolling waves being such a predominant feature.

spinyoakslugcaterpillar06-04-15Among its host plants, the Spiny Oak Slug Caterpillar eats the leaves of Oak (no big surprise there), Hackberry (also no surprise), Ash, Cherry, Willow, and many other trees. Though we yanked out the Hackberry seedling — it was growing right in the middle of a multi-trunked Yaupon — we took the caterpillar over to another Hackberry being allowed to grow.

Finding things you didn’t know existed is so fun!

Sad News… Nature Struck Us a Blow

No pictures, just an update. With a sad heart, I have to tell you that our Eastern Screech Owl family suffered a tragic blow. A bee swarm, on the hunt for a new cavity to call home, found our owl house and decided to move in. Unfortunately, our 3 young owlets were still inside, and sadly we couldn’t help them, nor could their parents. The bee colony, in typical swarm fashion, was huge. The bee rescuers who came, along with other folks we talked to, said it was very unusual for bees to move into an occupied house. But our owlets were still quite small, and my guess is the bees didn’t see them as much of a concern.

We are devastated and are mourning the loss of 3 innocent baby owls. Such a pointless death, Mother Nature. But despite our unhappiness at the bees, they now have their own “official” hive and will hopefully work hard making honey for themselves and the beekeepers who rescued them.

Since this is our second swarm in a year, one of the bee rescuers brought out a special bee box to entice the next group of bees to move in there instead of our owl box. Let’s hope it works — perhaps we can be a regular source of bees for them, and something positive will come out of this tragic situation. Mama and Papa Owl, I hope you will return next year.

Sometimes Camouflage Doesn’t Work

My last post was about camouflage, but the truth is, sometimes even the best camouflage can fail you, and you become lunch (well, in this case, a dusk-time breakfast for the baby owls inside the nest box). Here one of our screech owl parents is delivering to their owlets what appears to be a walking stick insect.


It always amazes me what incredible nocturnal hunters owls are, but especially screech owls. It’s easy to imagine larger owls hunting bigger active animals, such as rats, rabbits, and even skunks. But screech owls bring home caterpillars, worms, lizards (including diurnal ones that theoretically shouldn’t be quite as active at night but perhaps are), scorpions, centipedes, and apparently stick insects. Sure, I can still imagine some of those being reasonable prey, but caterpillars? Some of them barely move (relatively speaking) and often blend in among bark, foliage, etc.

Owls, I am impressed and quite jealous of your superior eyesight and stealth ability. I shall continue to watch you exhibit your skills for those few minutes at dusk when I can still see you before the darkness takes over and my limited nighttime vision fails me. Oh, to be an owl!

Edit: My friend Justin reminded me that this video of awesomeness exists. For your viewing pleasure, and thanks to its creators:

Now You See Me… Now You Don’t

It just so happens that at work I’ve been creating new nature activities for kids, this time the focus being how animals utilize camouflage for survival or for catching prey. I’ve been gathering pictures of camouflaged animals, which is a bit of a challenge because I have to actually locate the hidden animals first.

Today I rescued a moth trying to escape through our chicken coop window and was ecstatic to realize it was an underwing moth (so sorry to the other moth that one of the chickens got to first). Perfect camouflage photo op ahead, as long as the moth didn’t fly away too fast!


Worn out from the window experience, the moth was happy to take a rest against the bark of an oak tree, a perfect spot to blend in. Can you find it in the photo above? Once you’re confident you see it, click here to verify.

In the case of North American underwing moth species, they depend on oaks and other native tree species not just for protection, but to feed on during their larval stage. They earn their common name for the brightly colored wings hidden underneath the peppered ones.


That flash of color might startle a would-be predator to reconsider going for the moth in some circumstances. But it’s the patterned brown, black, and gray wings, when closed, that likely afford the moths the best protection against a woody background.

For the kids’ activity I’m working on, we’ll be playing with creating and testing our own creations, with matching coloration and patterns, against objects in both nature and the classroom. I ordered a large spider craft punch, perfect for the activity (at work we’ll also be getting bird and butterfly punches). The kids will be hand-coloring their animals according to the area in which they want their animals to hide, but at home I found some colorful magazine pictures for quick cut-outs. How quickly can you find the spiders in the following pictures? Among the following 4 pictures, there are a total of 7 spiders. I expect that you’ll be able to find them relatively easily, but consider as you do what makes them stand out or blend in. Which spiders would likely be most effective at hiding then ambushing their prey?camouflageactivity20150523 camouflageactivityB20150523 camouflageactivityC20150523 camouflageactivityD20150523

In some of our afterschool classes, we’ll also be using animal camouflage studies for biomimicry activities — students will design their own inventions that incorporate camouflage techniques to avoid detection.

Animals go to great lengths at times to avoid detection. While some are built-in through concealing and disruptive coloration, other animals will disguise themselves or exhibit other behavioral adaptations to avoid detection. Of course, these survival adaptations and strategies have evolved over long periods of time through the natural selection process. One of my local favorites is the Trashline Spider; it gathers insect carcasses in a line on its web and then hides among them.


Just think how many animals might be hidden in plain sight near you as you take a walk in nature!

Reptiles in the Garden

Last weekend I gave my last presentation of the spring, and the very next day I seized an opportunity to work in the garden for a change. It was a beautiful day, and of course in my eagerness to be outside, I forgot both hat and sunscreen, and I soon sported my first and hopefully only sunburn of the year. I wasn’t alone out there, either. Basking in the warmth of the day was this beauty, a male Texas Spiny Lizard (Sceloporus olivaceus).


He was so chubby that at first I thought it must be a female ready to lay eggs, but nope, his markings clearly indicate otherwise. It’s a little hard to see it in this image, but he has light blue stripes along the sides of his belly — females don’t have these.


He wasn’t afraid to let it all hang out, clearly. I’d like to think that if a female were nearby, he suck that chubby belly in, puff out his chest, and do a handsome pose. Clearly he should be practicing those defensive/offensive push-ups male Texas Spiny Lizards are known for (when confronted by other male Texas Spiny Lizards in their territory) — perhaps he could get in better shape. But then again, perhaps this round belly equates to “hot” in the lizard world.


On the other hand, he’s limber enough to do the splits, and to stay in that pose for a while while I took pictures.


Check out the markings on his gorgeous tail.


Yes, yes, you’re a pretty handsome insectivore after all, little big guy. TXspinylizardD-hole04-26-15

My son said he saw the lizard coming out of this hole in one of our raised beds. I wonder whether the lizard was using the little tunnel as a cool haven, or whether a female might be prepping to lay eggs in there. I haven’t had a chance to inspect the spot since then to see whether the hole has been covered up or not. If it is, I suspect there might be little eggs inside.


Despite being described as an arboreal species, I have these Texas Spiny Lizards all over my garden and rarely see them on a tree. I guess they have too much to feast on in the garden area. I imagine they’d blend in much better on the bark of a tree than on the wood of my veggie beds or on the rocks around on the pond. But I’m happy they’re willing to hang out on the ground with me.

Getting back to working on the garden, I decided to tackle the weeding of a small perennial patch in the backyard, and in doing so had to move aside several bordering rocks. It’s best to move such rocks carefully — all sorts of little creatures might be sheltering under rocks to stay cool and out of the light (scorpions, centipedes, snakes, etc.), and one wouldn’t want to get a jolt of surprise or worse, pain, from reaching under a rock blindly. But under one rock, I did find a wonderful garden resident.


It was a Tantilla snake, one of the Blackhead species. Some people call them Centipede Snakes, named for their favorite food. The small snakes also eat scorpions and other invertebrates. Like their prey, they are nocturnal and favor rocks to hide underneath. They are colubrid snakes and are non-venomous.


I think this snake must have realized I’m a Snake Whisperer and completely calmed down in my hand. What a beauty. It was probably about 10-12 inches long.tantillasnakec04-26-15

Of course, as soon as I set it down, the snake scurried off for shelter, making use of its fossorial lifestyle and digging right into the earth. But we were able to get a quick picture — you can see the earthy coloration of the rest of the snake’s body.

And so I went back to weeding that garden bed. Lo and behold, under the very next rock was another snake, a much smaller one. It was a Leptotyphlops snake, or a blind snake, about 6 inches long. It looked almost silver in the sunlight but shows a pinkish undertone in the pictures.


These little burrowing, nonvenomous snakes are often confused with earthworms due to their size and coloration. Their eyes are reduced in functionality, serving only to perceive light — they aren’t truly blind, but very nearly so. They spend most of their lives underground.


The main diet of blind snakes consists of ants and termites, along with their eggs, larvae, and pupae. It is believed that the snakes can follow the pheromone trail left by the insects in order to find their colonies. Sometimes blind snakes will also eat millipedes or centipedes. Their scales are smooth and tightly overlap, helping protect the snake from the bites and stings of ants. The tail ends abruptly, mostly rounded with a small point at the very tip.


This little snake was quite a wiggler, and I used a clear bowl with some leaf litter to hold the snake for a moment while I snapped a couple of pictures. But I didn’t want to stress the little snake out — I quickly returned it to the safe haven of its rock in the garden.

I’m so glad to run across these reptiles from to time in my garden. It means my wildlife habitat is functioning well in terms of the ecosystem —  predators such as lizards and snakes are natural and very important pest control. Of course at night, they have to be careful, too — we have hungry screech owls that are even higher in the food web, and they’d love a chance to catch one of these little snakes. The lizards, being diurnal, might be safe if they have a good place to hunker down at night. Always excitement in our backyard!

Baby Squirrels Peek Out… Also, Owls!

Despite our amused annoyance that a squirrel family is squatting in our new-and-improved owl house, it’s hard not to be heart-touched by the curious and playful little babies. They’ve been growing fast and are already peeking outside and trying to figure out how to safely get out of the house.squirrelsc04-10-15squirrelsa04-11-15 They also seem to share the window a little better than last year’s owlet siblings did.squirrelsd04-10-15

I just wish they wouldn’t chew on the box!screechowl04-11-15

The latest exciting news is that we have officially confirmed that we do indeed have an owl family in the older owl box, which we had moved to a different tree last fall. Unfortunately for us, though, it’s the one without an owl camera inside, so we have no idea yet how many babies are inside. But the fact that we see Mama Owl regularly now means that the babies must be big enough that she needs a window seat. It’s going to be harder for us to view the owlets as often as in years past — this owl box is wayyyyy in the backyard. But we’ll try!

And the Owl Cam Reveals… Squirrels

For the past few years, we’ve enjoyed watching Eastern Screech Owls nest in our two owl boxes. Last summer, after we had to remove a box filled with swarming bees, we used the opportunity to build a new box complete with a camera for peeking inside. We had hoped that the owls would just move right in this spring, but unfortunately each time we checked the Owl Cam, we found no residents — until last night, that is. What we found was not feathered friends but instead furry ones. There’s a squirrel family in our owl box. Sigh.


But they are pretty darn cute. As much as we would prefer the owls, we can’t evict this little family of wiggling, curious critters. We can only hope that our owls have moved into our 2nd box in the far backyard (where there is no camera).squirrelsowlboxb03-24-15

Somehow we went from a completely empty box to a full nest — these little squirrels already have their fur and have big open eyes. Clearly it had been a couple of weeks since we checked the owl cam! There are at least 4 babies in there with Mama Squirrel — possibly 5. Last night when we discovered them, they were nursing and sleeping away. This morning, they were crawling all over Mama and reaching up toward the light.squirrelsowlboxd03-24-15

Mama was not getting any sleep, so when she’d had enough of the little ones crawling all over her, she set about to grooming each of her infants.squirrelsowlboxe03-24-15

They got drowsy right away, and Mama soon joined them for a nap.squirrelsowlboxf03-24-15

At first one little babe just refused to settle down, until it tucked itself under Mama’s tail for a cozy spot.


Here’s a view in full-color mode. And there you have it — a new family of naughty little squirrelsies to wreak havoc at local bird feeders and drive our neighborhood dogs crazy.

The Herald of Spring

This morning my dogs and I visited our favorite leash-free nature-plenty park for a bit of exercise. We enjoyed following the paths through a winter assortment of evergreens, bare-branched deciduous woody plants, and golden-to-brown spent grasses and herbaceous plants (granted, the dogs were far more interested in animal smells while I, on the other hand, forego those risky smells and instead admired the plants). But I pulled up short when I spotted this treasure among the winter scene, tiny yellow-green blooms looking like miniature fireworks among the brown branches. I knew immediately that Elbow Bush was announcing the imminent arrival of spring ahead.


Elbow Bush, or Forestiera pubescens, is a deciduous Southwestern shrub that blooms much earlier in the year (Feb-Mar) than most other plants in the region. In fact, another of its nicknames is Spring Herald. Its blooms, which open before new leaves bud out, are important nectar sources for early-emerging butterflies and other pollinators. Later on, the female plants will produce dark-blue berries that are a favorite of wildlife.


Yet another name for Forestiera pubescens is Stretchberry. But here in our area, I know this shrub best as Elbow Bush, a name earned because the plant typically branches at right angles. It has tremendous wildlife value and makes a great understory addition, but gardeners should note that it does have a thicket-forming habit. So perhaps it might serve a naturalistic landscape best.

It won’t be long, and this plant like so many others will be covered in green foliage. Also spotted in bloom today — Mexican Plum, Agarita, and one wee little bloom on a Mountain Laurel (and all three were deliciously fragrant, too — I couldn’t help but check). Spring cometh!