It’s a breathtaking sight in fall and winter: a huge flock of blackbirds swirling, billowing and gyrating in the air, seemingly of one mind. We witnessed such a spectacle near Augusta last weekend when a particularly large blackbird flock dipped and twisted over a field like an aerial ballet.
Not only are these coordinated mass movements mesmerizing, they also are bewildering. It sounds incredible, but scientists have found that such flocks aren’t led by a single bird. Instead, any bird in the flock may trigger a sudden maneuver if it abruptly changes speed or direction. The other birds instantly follow, regardless of the flock’s size.
The bird that sparks the change may have spotted some food or be responding to a predator, such as a hawk or falcon. Whatever the reason, the information is transmitted lightning-fast across the entire flock, which then acts in unison to quickly change course.
Some people call such flocks “murmurations,” which originally applied only to the massive flocks of starlings that formed in fall and winter in Europe. Dating back to medieval England, the term came about because of the soft murmuring sounds from the flocks.
Natives of Europe, starlings were brought into North America in the 1880s by two New York men who wanted the city to have every bird species mentioned in Shakespeare’s plays. But the starlings spread across North America, which now has 200 million starlings.
Blackbird flocks seen in Georgia and elsewhere during fall and winter are likely mixed flocks that contain starlings as well as other blackbird-related species: red-winged blackbirds, rusty blackbirds, common grackles and brown-headed cowbirds.
A couple of reasons have been given for flocking in winter. One is that flocks offer better protection from predators. Also, thousands of pairs of eyes may be more effective than one pair in finding food.
IN THE SKY: From David Dundee, Tellus Science Museum: The moon will be new on Friday. Only three planets are visible right now. Mercury is low in the east just before sunrise and will appear near the moon Thursday morning. Venus is low in the east just before sunrise and will appear near the moon on Monday morning. Mars is low in the southwest at dusk.