When my partner got home from a Boston Symphony Orchestra (BSO) concert last week, he asked me if I knew what a murmuration was.
I said of course! It’s when a bunch of European starlings fly together. But how did starling murmurations come up in an orchestra concert?
Well apparently, the BSO co-commissioned a piece from composer Elizabeth Ogonek; the piece she created is called Starling Variations and captures the image of a murmuration of starlings.
In the spirit of this piece, let’s take the opportunity to take a closer look at this extremely common bird.
Originally European
European starlings (Sturnus vulgaris) are native to Eurasia; in fact, they are known as ‘common starlings’ or simply ‘starlings’ in Great Britain and Ireland.
However, there’s a good chance that you’ve seen a European starling if you live in North America, even if you’ve never been to Europe. European starlings were brought to North America in the early 1890s. Shakespeare enthusiasts wanted America to contain all the birds Shakespeare ever mentioned in his works, so they released about 100 European starlings in New York’s Central Park.
Although it took a little bit to get going, Central Park’s population really took off – there are over 200 million European starlings in North America, ranging from Alaska to Mexico. They are common in cities and towns, and you’ve likely seen them in lawns and city parks, stabbing their bills into the ground as they look for insects.
Because European starlings only recently (relatively) arrived in North America, they are all very closely related. All the European starlings in the continent today are descended from those birds that were released in Central Park in the 1890s. As a result, there is a lack of genetic diversity in the North American population – a European starling in Virginia is genetically almost identical to a starling in California. This lack of genetic diversity is usually a bad thing for species, as it makes them much more vulnerable to things like disease. However, the European starling seems to be thriving in America so far.
What color are they really?
European starlings have a very distinctive plumage, and one that changes quite dramatically over the course of the year. Their feathers are a glossy black with a metallic or iridescent sheen.
In the fall, however, European starlings grow new feathers. These feathers have white tips, which give European starlings their autumn / winter white spots.
Now, most birds change into their breeding plumage by molting their feathers. But not European starlings! By the time spring comes around and breeding season is about to commence, the white tips of their feathers have completely worn away. This type of feather changing is known as ‘wear molt’ – instead of molting their feathers, their plumage changes based on everyday wear and tear.
Murmurations
Okay, murmurations – while I described it before as a bunch of European starlings flying together, it’s sooooo much cooler than that.
European starlings are gregarious (the scientific word for tending to form groups or flocks) birds, so they form flocks. And I mean BIG flocks. In the UK, starlings will form flocks of five to fifty thousand individuals. Some murmurations have been counted to contain up to 750,000 starlings. When that many birds fly together, all their wings create a loud rushing sound, leading to the name ‘murmuration.’
Now, large flocks aren’t necessarily that special. But what is special and unique about European starling murmurations are the complex patterns they create as they fly together and the coordination necessary to pull it off. It’s thousands of birds swooping and flying together, yet somehow no one is colliding with each other. The flock almost takes on a life of its own. You can see what a murmuration looks like here.
How starlings murmurate is somewhat of an open question. Research by Andrea Cavagna and Irene Giardina suggests that starlings maintain their movement via scale-free behavioral correlation. Basically, each individual starling keeps track and moves based on the movements of its neighbors (about 7 other birds). If one neighbor starts to turn, you’ll start to turn too.
Research by Charlotte Hemelrijk also suggests that European starlings are playing a form of follow the leader and copying the behavior of the nearest bird. These sorts of behaviors might confuse predators and make it more difficult for them to pick off birds that are falling behind the flock.
But why do European starlings form murmurations for so long? A murmuration can be flying and wheeling through the sky for 30 to 45 minutes. This uses a lot of energy and could be detrimental to survival. After all, it would be safer to just chill in your roost instead of flying around for a while and advertise to predators where you are. Research has also showed that murmurations don’t seem to provide warmth to individuals – there’s no correlation between temperature and murmuration size.
Why starlings murmurate when they could be doing something safer and less energy-intensive like sleeping is an open question. Although we don’t want to attribute too much intention to these animals, one possibility is that European starlings murmurate because it’s fun. These birds are very intelligent, and so murmurations could just be something that they like to do, like a form of dancing or playing. We won’t know for sure, though, until we do more experiments to rule out other explanations.
An invader
While their murmurations are beautiful, European starlings aren’t really the best birds to have around in America. Remember, they’re a non-native species that has done exceedingly well – the only bird species that outnumbers European starlings in the U.S. is the red-winged blackbird.
To be fair, European starlings do like to eat insects that can cause crop damage. In this way, European starlings can be beneficial in reducing the number of insects that can damage crops on farms.
However, in eating these insects, European starlings reduce the amount of food available for the native birds that would traditionally be feeding on these bugs. In addition, European starlings may use nesting sites traditionally used by native species like bluebirds, thus displacing them and potentially decreasing their population. Finally, European starlings may help spread the seeds of invasive species of plants, as their digestive systems increase the chances some seeds will germinate.
European starlings are also harmful economically. If the birds eat all the insects, they will turn to eating and destroying a farmer’s crop instead. A 2000 study estimated the damage European starlings have havocked on the agricultural industry as $800 million a year. European starlings may also have implications for airports – flocks of starlings can cause issues by hanging out on runways or even flying into and clogging up airplane engines.
Now, as a non-native species, European starlings are not protected by the Migratory Bird Treaty Act. This law was passed in 1918 to end the commercial feather trade and serves to protect bird species from harassment and death by companies and individuals. Basically, you can’t mess with birds protected by the Act or keep bird parts like feathers (although there are some exceptions for Native Americans using bird parts in religious ceremonies). However, it is perfectly legal to remove or exterminate European starlings in the United States, and there are things you can do to reduce the population around your house if you desire.
At the end of the day, my feelings about European starlings are complicated. I think they’re a pest here in the U.S., but I also find their murmurations captivating. Someday I’ll have to travel to Europe to see one in their natural habitat.
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