One of the exciting examples of design in the living world is the nesting behavior of birds. We have previously reported on data about birds that nest in peculiar places to protect their eggs and their behavior to thwart predators. We have all seen birds building nests in cliffs or under roof structures, but predatory birds like eagles and hawks can still land on the nests and eat the eggs or baby birds. Scientists have discovered that some birds use spikes to protect their nests from even bird predators.
Researchers in Belgium, the Netherlands, and Scotland found nests in which birds have used long spikes to make it difficult for predators to get to their eggs or chicks. One crow’s nest in Antwerp, Belgium, had 1500 long, sharp spikes. They would make reaching the nest’s occupants extremely difficult for any hawk or eagle. It would also deter other predators, such as cats.
The nests of carrion crows and Eurasian magpies have been found with spike defenses. These birds have used whatever sharp objects they can find in urban areas to build their fortress, including plastic pieces, nails, screws, and knitting needles.
Birds use spikes to protect their nests because God has built into the DNA of various bird species the ability to do unique things to survive. The more we learn about the natural world, the more we should be amazed at the intelligence and design behind all kinds of life on Earth. “We can know there is a God through the things He has made (Romans 1:20).
We tend to ignore the hidden intelligence of design in the natural world. One great example is the wisdom of bird nests. We see that wisdom in a wide variety of bird nest designs in how and where they build and how they use them.
You may think that bird nests are where birds live, but that isn’t true. Birds do not sleep in their nests, and most birds never return to their nests once their young can fly. Instead, when it’s time to sleep, birds roost in safe, comfortable places. This may be a well-sheltered tree or a sheltered spot under an eave. Perching birds have locking tendons in their legs and feet so they can hold tight to branches, even when they are sleeping.
When building their nests, birds use ingenious ways to protect their eggs and baby birds. Two main techniques are camouflage and making nests hard to reach. For example, hummingbirds weave their nests with natural objects to blend in with tree branches. Cactus wrens build their nest in sharp-spined cholla cacti, which few predators can navigate. Birds use common materials such as lichens and leaf scraps held together with spider web threads that can stretch as the young grow.
Some birds set up decoys by building an empty dummy nest in addition to their real one. Flycatchers weave snakeskins into their nests to frighten away squirrels and other nest raiders. Seabirds lay pear-shaped eggs on cliffs beyond where predators can climb. The shape of the eggs keeps them from rolling off the cliff. Some birds will nest within a wing’s reach of each other, so there are many defenders against an approaching predator.
Small birds sometimes build their nests near large birds for protection. Sparrows and hummingbirds nest within an abandoned eagle’s nest or Cooper’s hawk nest. Snow geese nest near a snowy owl’s nest. Egrets and herons nest above alligator ponds to keep raccoons away. Some wading birds fake an “incubation pose” to decoy predators from their actual nest location.
Other bird nest designs include a floating nest of aquatic vegetation that moves with changing water levels. The decaying vegetation also generates warmth to help incubate the eggs. Canadian jays situate their nests, so they have southern exposure to give them extra heat. All birds line their nests with their own feathers so the featherless baby birds can stay warm. Some species will even pull fur from dogs and other animals to line their nests for warmth.
Bird nest designs take advantage of many locations to give their babies a chance to survive. For example, Wrens, barn swallows, purple martins, and house finches use locations that include human structures, such as highway overpasses, abandoned cars, skyscraper ledges, and traffic lights.
Observing the many bird nest designs is a great way to see the wisdom and design God gave them. In Job 39, God challenges Job to explain how various birds do what they do. Job responds by saying, “Who is he that gives counsel without knowledge? Therefore have I uttered things that I did not understand, things too wonderful for me which I did not know about” (Job 42:3). The natural world displays so much design and wisdom that we need to have that same attitude.
You may look at a bird’s nest and assume that it is just a pile of twigs randomly thrown together. However, physicist Hunter King of the University of Akron says birds use the twigs in a way that is “totally mystifying.”
Dr. King has done an interesting experiment with the design of bird nests. He took a piston and compressed 460 bamboo rods arranged inside a cylinder in a form similar to the construction of an ordinary bird nest. As the piston applied more force, the sticks slid against each other, rearranging the contact points. As a result, the rods acted as a group and became stiffer and more resistant to deforming.
The new contact points stiffened the “nest,” preventing the twigs from further flexing. King says the fact that birds seem to have a sense of how individual twigs will make a nest with the right characteristics is “something we don’t know the first thing about predicting.”
So a bird’s nest is more than twigs randomly thrown together. Birds construct them to protect what they value—eggs and chicks. From an engineering standpoint, this research will allow scientists to create new structures designed to protect things that humans value. From an apologetic perspective, this is one more example of the design built into the DNA of living things to allow them to survive in the natural world.
