bird nests
I've been trying to learn more about bird life as they experience it, not just from my human perspective. I figured nests were a good place to start my quest.
Not all birds build nests but for those that do, there are two types of nests: breeding and roosting nests (roosting nests are used for resting...seems like scientists were thiiiis close to calling them resting nests...maybe next time).
Nests have many benefits, including providing a climate-controlled environment where temperature and humidity are (pretty much) exactly what eggs and nestlings need to thrive. They also provide a safe place to hide from predators while growing their wings.
But there are several threats to nest health, including bacteria/parasites, weather, and predators.
parasites
Apparently, baby birds in the "altricial" category (which includes any bird species that needs constant parental care as babies) poop into membrane sacs, basically diapers, which parent birds either throw out or eat(!!) to keep the nest clean. Parent birds also strategically use certain plants to repel parasites, similar to how humans might use essential oils or lavender plants to keep insects away from our home.
weather
As I wrote about in my blog post "mockingbird markets, museum specimens, and important women," Verdin nests are so insulated that they can conserve up to 50% of their energy needed to stay warm in the winter. Their summer roosting nests (also spherical) have the one and only opening facing toward the direction that prominent winds come from, aiding with cooling. Local birds co-evolved with local weather, so they know how to nest and survive in even extreme climates.
predators
To stay safe from predators (of which there are many), birds employ several innovative strategies.
For example, some hummingbirds like to nest near Cooper's Hawk nests, despite the fact that Cooper's Hawks eat smaller birds. This seems counterintuitive, but apparently hummingbirds are so small they're not worth eating, so Cooper's Hawks leave them alone. And birds that would normally try to eat hummingbirds are usually birds that Cooper's Hawks do eat, so they're not willing to risk it. Like Ivan Phillipsen said in his podcast episode about nests, this is a classic case of "the enemy of my enemy is my friend." Genius.
Other birds like Marsh Wrens build multiple decoy nests in the same location as their real nest, confusing predators. Kind of like when you're planning a surprise party for a friend but you accidentally text them details but you know they're in a work meeting for another hour so you just spam them with random texts, articles, pictures, and gifs hoping they'll see you sent 37 messages and just not read any of them. Or a house of mirrors. Same thing.
It just goes to show that survival strategies on planet Earth can be remarkably universal!
bird nests and humans: the curse of the microplastic
If Hollywood wanted to make a wide pivot in the Pirates of the Caribbean franchise, "The Curse of the Microplastic" might be a good tagline. Just sayin.
Sadly, our beloved neighborhood birds have microplastics in their little bodies. Researchers have noticed that urban nests are increasingly constructed with pieces of plastic, since it's easily found in trash cans or strewn about the street. And studying those precious, precious bird diapers we talked about earlier indicates that microplastics are getting into baby birds' bodies, likely through soil, plants, other animals, and perhaps even their newly-renovated plastic nests.
This was such a bummer to read. The only silver lining is that afterwards, I felt a strong urge to immediately reduce my plastic consumption. And while there are areas within my control that I can and will be more intentional about (like reusing/upcycling more), there are other areas where it seems damn-near impossible to cut back (like how most grocery items are encased in plastic). It's easy to feel hopeless but I'm reminding myself that some progress is better than no progress. And I don't have to solve my plastic use all in one day--a lifetime of small intentional decisions accumulates into a huge difference.