It was late summer in the coastal plain forest. At mid-day, it was quiet but not quite silent. There was a background buzz of flies, then the whine of a mosquito in my left ear. Swat! Then I heard a sound like water coming from the trees.
A flock of grackles, hundreds perhaps, were drifting through the scene, making low clucking sounds that together form a sound like water flowing over rocks. They moved from tree to tree, in the same direction, left to right. Then something startled the flock, and it rushed away with a big whoosh. But the birds didn’t go far. A few minutes later, they resumed their movements from tree to tree but in the opposite direction.
This is the time of year when grackles and blackbirds form large flocks. You might see large swarms that move like shape-shifting ovals above the fields, forests and waterways.
Watching them move through the woods was fascinating. They were like flying pieces of obsidian drifting before and through the dappled green-and-yellow background. Grackles are close in size to robins; they have yellow eyes and long tails.
Suddenly an amber-colored form, back-lit with sunlight passing through its un-feathered wings, came out of the flock of grackles and flew counter to the movement of the birds and away from the center of activity. It was a little brown bat, common but nocturnal and not usually active in the day.
The grackles made me think about the stories I’ve heard about the huge flocks of now-extinct passenger pigeons that once swarmed over North America. There were so many pigeons that they would block out the sun as the flocks passed through the sky. There were so many birds that the flocks could take hours, even days, to pass over a particular point. It is difficult to imagine that there once were so many when now there are none.
Here in these late-summer woods in 2010, the trees are still full of life. The grackle display was small compared to the flights of the legendary pigeons. But it is still something to celebrate — with a note of caution about a potential threat.
Will Bats Join the Ghostly Passenger Pigeon Flock?
The bat made me think about a serious threat it and its kind face from a mysterious fungal disease known as white nose syndrome. The population of little brown bats, the most abundant species in North America, has been devastated in large areas in the Eastern U.S., according to the Fish and Wildlife Service. A worst-case scenario is extinction.
The fungus grows on the nose, wings and ears. One theory is that it irritates these membranes, causing bats to wake often during hibernation and burn so much energy that they starve to death before spring. Additionally, there are signs the fungus is directly damaging wings, which are important for maintaining water balance and blood pressure. Scientists are trying to find a cure.
Ecologists study the complex and delicately balanced interconnections within an ecosystem. They fear that the loss of key species could cause the web of life to unravel in unpredictable ways. Bats eat a lot of insects, and their role in maintaining the balance of nature is critical. The impact of the loss of little brown and other bat species is hard to calculate, but it could be devastating to other wildlife, to agriculture and ultimately to humans.
How strong the connections are we might understand better if the bats disappear. But I would rather have the bats and keep the mystery. It will be best if some questions are not answered.