For the Birds Radio Program: Chickadees and West Nile Virus
West Nile Virus appears to be killing a lot of chickadees in Illinois and Wisconsin.
Every morning at first light I’ve been putting a few dozen mealworms into a plastic bowl that I have on top of a platform feeder on my upstairs home office window. I whistle, and within a minute, a flock of chickadees flies in. One by one they zip into the bowl and grab a mealworm or two, or in the case of one rather bold little chickadee, three or four mealworms, and they fly off to eat them in my trees.
Chickadees are the Norwegian Bachelor Farmers of the bird world–very sociable, ya sure you betcha, but uncomfortable when other chickadees get too close, so they prefer being widely spaced while eating. But as they finish their treats, they each head back to the window and grab more mealworms, until within a few minutes, the bowl is again empty.
Chickadees are quite possibly the world’s most endearing birds. When I started a little movement to make the Black-capped Chickadee Minnesota’s Emergency Auxiliary Backup State Bird, I quickly got almost a thousand signatures (I was shooting for 10,000) along with dozens of phone calls and letters about how much comfort people with terminal diseases or recovering from strokes took from watching chickadees. You can hear the smiles in people’s voices when they talk about chickadees.
So it’s scary indeed that West Nile Virus and quite probably the overuse of pesticides in reacting to the disease have been killing chickadees. In the Chicago area, 74 trained observers conducted an extensive, 6-county survey and discovered that chickadees have been completely extirpated from large areas. The areas where the chickadees are rarest coincides with the area where human West Nile cases have been most common . In Wisconsin, at the Little Suamico Ornithological Research Station on Western Green Bay, researchers have been banding chickadees for over 30 years. At this time of year, when they normally have 35-55 chickadees, they have only 7. In most years, the chickadees they have span in age from that year’s hatch to birds 5 years old. This year there was one unbanded bird, and of the 6 remaining ones, five were hatched this year, and one last year. All the older birds, which are usually there year after year, have disappeared.
During migration, the numbers of migrants banded at Little Suamico were also exceptionally low. Red-eyed Vireos were down 50%. They banded only 3 Song Sparrows, when normally they’d band a few every day. Wrens were virtually non existent. Losing so many songbirds is tragic, but losing chickadees seems somehow even more obscenely tragic.
It’s critical that people start planning now for how we’ll address the problem next year, when Wisconsin and Minnesota will most likely be in the epicenter of the disease. The most effective pesticides for controlling mosquitoes are the bacterial ones– Bacillus thuringerensis specifically developed for mosquito and fly larvae can target mosquitoes without hurting birds or dragonflies and other beneficial insects. Since the mosquitoes that spread the virus are mostly the kinds that breed in backyards, in gutters, old tires, and birdbaths and other places where standing water exists, it’s important to make sure these breeding grounds are eliminated.
Of course, you can safely keep your birdbaths going if you’re careful to change the water daily. But mosquitoes have very short reproductive cycles, so if you don’t have time to change your birdbath often, it’s far safer for birds to leave it empty. Aerial spraying kills fewer mosquitoes than the larval bacterial approach, and kills many more non-target insects and other animals, including birds.
After Wisconsin Bird Net posted a depressing e-mail about the chickadee situation, one of our posters, Wayne Rohde, wrote, “After reading [the post about disappearing chickadees], I immediately went outside, sat down near our feeders, and simply relished the characteristic little notes and buzzes of the handful of chickadees that continue to occupy our yard. I don’t have anything to contribute to the body of information re: WNV and chickadee populations, but I do intend to never take these friendly visitors -whose presence brightens so many otherwise drab fall and winter days-for granted.
That was Wayne Rohde, and I’m Laura Erickson, speaking for the birds.