If you live in the U.S. or the UK, you may have been lucky enough to have seen a murmuration—the eerie, undulating black cloud formed by a flock of starlings in flight. Now, birders can put those observations to good use in the Royal Society of Biology’s second annual Starling Survey.

Starlings occupy very different niches in the U.S. and the UK. Here in the States, the sharp-beaked, iridescent birds are considered a pest. They’re one of only three bird species that aren’t protected by law. The starling is not native to North America; it was introduced in 1890 in a well-intentioned bid to bless North America with every bird species mentioned in the works of Shakespeare. The continent’s starling population started with just 100 birds; today, we have nearly 200 million. This is a problem for America’s native bird species, which can’t compete with the hardy starlings’ numbers.  

British starlings are an entirely different story. Their ranks are declining rapidly; since the 1970s, the population has fallen by 66 percent. To understand what’s happening, ecologist Anne Goodenough of the University of Gloucestershire initiated the first-ever Starling Survey last year. Created in collaboration with the Royal Society of Biology, the survey hopes to collect data on starling activity all over the world.

Taking part is simple: Each time you see a murmuration, note where you saw it, when you saw it, about how many birds there were, what the weather was like, and how long it lasted. Then add your data to the survey site. You can also share photos and other information using the Twitter hashtag #StarlingSurvey or by tweeting @Starling_Survey.

Keep your eyes to the sky around sundown each day. You might just see something amazing.

Header image via pyropix, YouTube