The big picture
There was a flock of birds at Audubon (recently) whose population has dropped by 85% to 99% in the last 40 years. That’s a huge number. For every 100 birds around when I was born, only one exists today. No one even knows what has caused the decline and, truthfully, no one has really noticed it except people who are really into birds and researchers.
The bird in question is the Rusty Blackbird. One of the reasons no one really knows about these birds’ disappearance is because it is one of many different black birds and often goes unnoticed. It is a Red-winged Blackbird sized bird with black feathers, a pale yellow eye and a rusty hue around the head and shoulders. They live in swamps far to the north and spend the winter to the south. Rusties come through in a wave in the fall as they migrate south and again in the spring as they head back north. While not a resident bird, they rely on our swamps for food and shelter as they travel.
There are scientists dedicated to finding out why this bird is disappearing and websites set up to track their migration and numbers, but the truth is that most would never notice if they disappeared forever. Why should we care?
Ecosystems have been described as Jenga towers. An ecosystem is the interaction between plants, animals, water, soil and other non-living things. In essence, it is a Jenga tower with blocks made of different plants, animals, bacteria, earth, water and air. What happens when one piece is removed from the ecosystem? Perhaps not much. Perhaps the Rusty Blackbird is a small block whose loss leaves only a small hole in our ecosystem Jenga tower.
As time goes on, more blocks disappear from the ecosystem. Ash trees dies from Emerald Ash Borer, Hemlocks succumb to the Hemlock Wooly Adelgid. Elms and chestnuts have long fought their own diseases. The Jenga theory is that each loss of a plant or animal leaves a hole in the tower. The ecosystem may look OK, but is one block away from teetering on the edge of collapse.
Nature has so many moving pieces that it is almost impossible to look at what is happening and understand or predict how and why things are going on. If one important, but unnoticed, chunk of that ecosystem disappeared, it might go unnoticed. Adding and subtracting plants and animals can change many things in an ecosystem.
One recent example that came to my attention was a beautiful little Asian plant called Japanese Barberry. It had adorable little leaves that are beautiful in the fall, vivid red berries that stand out and tiny little thorns all over it that make it a perfect plant to place where you don’t want others to go. There are people who rave about its importance as a food source for quail and other birds.
One of the interesting things I learned this summer is that plants from other countries, like Japanese Barberry, can live in a habitat for decades without causing problems before suddenly breaking out and spreading everywhere. In some areas where it has spread, the bushes cover the forest floor.
According to research in Scientific American, part of the reason for this is that deer simply don’t eat it. Why eat thorny food when other good food without thorns is nearby. The other reason is that Japanese Barberry is very flexible and can grow in sunny fields or shady forests, happy in either wet or dry places.
One of the problems with this plant is that it can promote the spread of Lyme Disease. This disease can cause severe joint swelling, headaches, shooting pain and more. It is spread by ticks.
These ticks find the perfect habitat in Japanese Barberry. The closely spaced tiny leaves provide a humid environment where the ticks can stay active almost all day, instead of only 15 or so hours a day. The thorny branches provide a protected shelter for mice to raise their families and stay safe. Mice are the first meal for young deer ticks.
Mice are also the main place that ticks get infected with the Lyme Disease bacteria. While mice don’t seem to be affected, their blood does contain the bacteria that cause Lyme Disease.
Adding Japanese Barberry to an ecosystem creates the perfect habitat to breed and spread Lyme Disease. It creates the perfect place for the ticks to live in close proximity to the mice that provide their first blood meal, which often infects the tick with Lyme Disease.
When the plant was first planted here in 1875, this was not the intent. Japanese Barberry is a beautiful plant and people wanted pretty and exotic plants for their yards. Add the fact that deer don’t eat it and the plant becomes even more appealing. It was not brought here with the intention of spreading a disease that causes pain and suffering.
Ecosystems are complex places. Adding or subtracting elements can change significant things in how the ecosystem works. One plant covered with beautiful berries can spread through a forest to create a habitat that can be less friendly to people. There are many, many unintended consequences in our local habitats similar to this. The simple truth is that the actions of a few people in 1875 can seriously impact people almost 150 years later because nature is intricate and complex and we cannot predict how our actions will affect things 75 years after we are gone.
Jeff Tome is a naturalist at the Audubon Community Nature Center at 1600 Riverside Road, Jamestown, N.Y. More information about Audubon can be found by going online at auduboncnc.org or by calling (716) 569-2345.