Biodiversity Lessons from Bluebirds

March 2021, Eastern bluebird finishing off the staghorn sumac berries.

by Dr. Alexandra Moore, Senior Education Associate

September 2, 2021

When I saw the first bluebirds on March 8, I yelled, “No! Turn around!”

Not that I dislike bluebirds. Quite the opposite, in fact. But it was snowy and cold, and I wondered how they could possibly find anything to eat on such a dismal late winter day. Wouldn’t they be better off extending their southern vacation by a few more weeks? “C’mon you two, I didn’t have you penciled in until April at the earliest!” Alarmed, I pulled on my boots and plodded though the snow to clean out the bluebird houses. I drove down to Agway to buy a bag of mealworms, as these unexpected arrivals had caught me entirely unprepared.

The thing is, though, they knew what they were doing, and I didn’t.

Bluebirds are insect-eaters, but surely there aren’t enough insects out in March to support a hungry pair of birds. Despite the crummy weather – and despite the mealworms, which I never saw them eat – they were there in the backyard pretty much every day. Perching on the roof of the bluebird house, hanging out in the sumac trees, hiding in the honeysuckle bushes. As I watched the birds, I also saw the large, bright-red sumac fruit clusters grow raggedy and small. By the end of March, the formerly abundant honeysuckle berries were no longer to be found. In April the caterpillars, spiders, and other bugs emerged to feed my nesting pair.

The bluebirds gave me a lesson in biodiversity. I had assumed that they relied on one group of organisms – insects – for food, in a two-way exchange. Birds, bugs, end of story. In fact, bluebirds are omnivores, and not only enjoy but depend on the fruit from the previous summer for their early season survival.

Mama, Dad, and the Fam, 2021 (Eastern bluebird, Sialia sialis). — Mama, Dad, and the Fam, 2021 (Eastern bluebird, *Sialia sialis*).

I’ve often looked at the aggressive sumacs that grow by the barn and thought, “You know, I ought to clear those out…” Fortunately for the birds, I have too many other things to occupy my time and the sumacs continue to flourish. And fortunately for both birds and sumacs there are enough insects to pollinate the sumac flowers as well as feed the birds, ensuring that everyone will return next year to do this all over again. The more I think about bluebirds, the larger the circle of interconnected organisms becomes. In addition to food, the bluebirds need other plant species to provide cover from predators and materials for nesting. Those plants depend not only on pollinators, but also on the microorganisms and fungi in the soil, and other endosymbionts* within their plant tissue to ensure that they grow and reproduce. The insects that bluebirds eat need an even wider circle of plants to host their eggs and feed both larvae and adults. There is a staggering web of biodiversity just in the view from my back window.

The pandemic pushed me to look out the window and wander around the yard much more than I usually would. The pandemic also prompted my colleague Ingrid and I to organize PRI’s first Social Distance Bioblitz in April, 2020. A bioblitz is a community survey of living organisms within a specified geographic area and fixed time frame. While normally participants would get together on-site, the social distance aspect of these events allows people to observe wherever they are located within the region. Over the course of the pandemic we’ve run a Social Distance Bioblitz in each season, totaling six events to date. As many as 200 people have joined in these bioblitzes, helping to document the biodiversity of the eastern Finger Lakes region. In the spring and summer we typically identify >800 species during each event.

Bald eagle (Haliaeetus leucocephalus), Snapping turtle hatchling (Chelydra serpentina), Monarch butterfly (Danaus plexippus). Each of these organisms was photographed in the City of Ithaca, within 20 yards of the Cascadilla boathouse in Stewart Park. Preserving urban biodiversity is something we can all pitch in to achieve. — Bald eagle (*Haliaeetus leucocephalus*), Snapping turtle hatchling (*Chelydra serpentina*), Monarch butterfly (*Danaus plexippus*). Each of these organisms was photographed in the City of Ithaca, within 20 yards of the Cascadilla boathouse in Stewart Park. Preserving urban biodiversity is something we can all pitch in to achieve.

Monitoring our local biodiversity is really important and it’s an activity anyone can do. On-line tools and apps allow amateur naturalists to join professionals in observing and documenting the changing array of species that share our community with us. As a human community we rely on the ecosystem services provided by our natural environment. A natural community with a broad variety of plants and animals makes a healthier environment for humans to live in, and many species are essential to our continued well-being. For example, our food supply depends on pollinators, soil organisms break down toxic chemicals, plants help limit flooding, and trees soak up carbon dioxide while their shade cools cities in hot weather.

Monitoring the environment includes being alert to threats to our biodiversity. In central New York we have invasive plants and animals that threaten to displace some of our native species For example, the three insect species illustrated below are all common in the Finger Lakes region and all are at the top of the Department of Environmental Conservation’s list of invasive species. An invasive species is one that is not native to the region – it was introduced by humans – and causes harm to the environment, economy, or human health. Invasive species do this by reproducing quickly and by expanding into an area where they have no predators, or can outcompete native species for resources and space. Our native hemlock, oak, and ash trees are all under pressure from invasive insects.

Invasive insects observed in the Cayuga Lake basin: Hemlock wooly adelgid (Adelges tsugae), damage from Emerald ash borer (Agrilus planipennis), LD moth larva (Lymantria dispar). — Invasive insects observed in the Cayuga Lake basin: Hemlock wooly adelgid (*Adelges tsugae*), damage from Emerald ash borer (*Agrilus planipennis*), LD moth larva (*Lymantria dispar*).

The native species that I have highlighted here – bluebirds, bald eagles, snapping turtles, and monarch butterflies – are common summer residents in the City of Ithaca, and each has a different conservation history. The bald eagle is the national symbol of the United States and is probably the best-known success story of the U.S. Endangered Species Act. In the 1950s, there were only 400 nesting pairs in the 48 contiguous U.S. states, but their protected status, from 1966–2007, has allowed the population to recover. The eastern bluebird is the state bird of New York, and the NY population is relatively stable. Nationally, however, all birds are in steep decline. The North American Bird Conservation Initiative reported in 2019 that 30% of North American birds – 2.9 billion individuals – have disappeared in the past 50 years. The common snapping turtle is one of three snapper species native to North America, and is abundant in the eastern U.S. While adults are easy to spot, Ingrid and I were astonished to find a 2” hatchling (photo above) in the parking lot at Stewart Park – while we were shooting video for an upcoming bioblitz! Reptiles and amphibians generally are two groups that conservationists watch carefully, considering them to be indicator species of environmental stress. Monarch butterflies are another species in trouble. The U.S. hosts two populations of monarchs, one east of the Rocky Mountains, the other in the west. Western monarchs used to number in the millions, but the 2021 census turned up only 1900 individuals. In the east monarchs have declined by over 80% in the last two decades, placing the species at grave risk of extinction.

What to do? There are lots of ways to act: some actions take time, others require funding, some you probably already do. Get involved, locally or nationally, by supporting a conservation organization. Reach out to elected officials and make sure they know that biodiversity conservation is a constituent priority. Visit your city, state and national parks, and local nature centers. Would you like to see a Bald eagle? Head up to Montezuma National Wildlife Refuge. An Eastern bluebird? Try Sapsucker Woods. A Monarch butterfly? Come to the Cayuga Nature Center! Become a citizen scientist. Join our next Social Distance Bioblitz. Volunteer. Look out your window, walk around your yard. Take pictures, take notes. Observe!

And re-think your relationship to the native plants in your yard and community. The native species here in central New York have interacted with each other over thousands of years to create our complex local ecosystems. What I learned this year is to not be so quick to hurl the epithet “weed.” Things I placed no value on actually turn out to be quite important to the creatures I share this space with. And think about the upside: those sumacs I wanted to clear out? They’re better left in place, so my best action is no action at all. Less work for me, more food for the bluebirds. An amazing win-win. And the best part of this lesson is that I learned it from the bluebirds.

* Endosymbiont: Any organism that lives within the body or cells of another organism, most often in a mutualistic relationship. The Zooxanthellae algae that live within coral polyps are a well-known example, and the human microbiome consists of trillions of microbial cells inhabiting each of our bodies.