2006-08-26 / Columnists

Nature Notes

Island Birds Get Bolder with Prolonged Exposure to Humans
By Patricia Martin

This has been quite a summer for me. Earlier in the year, as my regular readers know, I was slugged, and now just yesterday, I was mugged. What is happening to Mackinac Island? Just to reassure you, both of these incidents involved members of the animal world. The first revolved around accidentally picking up a slug and having major slug slime smeared all over my shirt (luckily, my brother sent me Slug Slime Soap to help with any such problems in the future). The second incident occurred right after the reception for the Mackinac Island Community Foundation. My mother, myself, and a friend of mine decided to get an ice cream cone on the way home. While walking, pushing my bike and carrying my cone, a gull dive-bombed me and flew past me. We all laughed, but then he made a second pass, reached out with his bill and grabbed the edge of my cone and flew away. I was startled, but immediately ran after the bird with my bike and startled it enough to make it drop the cone. I picked up the ice cream cone and dropped it in the trash. You see, I did not want that gull to benefit from his crime. I was particularly bummed, as it was my first ice cream cone of the summer.

Above: Great Blue Heron Above: Great Blue Heron This type of behavior is not uncommon among gulls, particularly the ring-billed gulls who hang around town. I've heard many reports of people being dived at by these birds, but I think I was surprised that it would literally take it from my hand. Most people are familiar with the ring-billed gull, and I've written about them before. They have a white head, yellow bill and legs, and they have a black ring around the tip of their bill. The underparts are white and the back and wings are gray with black wing tips. The immature ring-bills have a gray back and brown wings and breast. These birds do not breed on Mackinac, but instead nest on some of the uninhabited islands and shores in the Straits area. They just come to Mackinac to feed. Before the advent of humans in this region, the ring-bills usually ate spiders and insects, rodents, earthworms, grubs, and scavenged for carrion. They also would skim the surface of the lake for aquatic invertebrates and fish. Today, however, they've become adapt at living on human waste, and apparently some human food that people were not ready to give up yet.

Below: Female and male Wood Ducks Below: Female and male Wood Ducks If you think that there are more ring-bills than there have been in the past, you're right. "Its tolerance for humans has made it a part of our everyday life" to quote the "Birds of Michigan" field guide. In the early part of the 20th century, scientists were not even sure if these birds bred in Michigan. In the 1940s, there were 20,000 breeding ring-bills in the state, and 20 years later, in the 1960s, you couldn't miss the more than 100,000 birds in Michigan, and that number has certainly not declined. Because of their numbers and the locations that they frequent - beaches, golf courses, fast-food parking lots, and parks - these birds have certainly adapted well to the expansion of humans, unlike many wild creatures. As one of my bird books put it, in describing places where one might view these birds, they listed the Great Lakes shores, large inland lakes, and "landfills and supermarket parking lots."

Another gull that I was recently asked about is a larger cousin of the ring-billed, called the herring gull. They're considerably larger than the ringbilled and, of course, they do not have a ring on their bill. They have a yellow bill with a red dot on their lower mandible. They have light eyes and pink legs. While they do eat human byproducts and are often seen at the dump, they're not as common as the ringbilled in urban settings or in downtown Mackinac Island.

Another odd bird behavior I was asked about recently involved another of our water birds, a duck. The person who talked to me about it wasn't sure what kind of duck it was that his wife saw, but she told him that the duck was perched on the branch of a tree along the bluff on the west side of the Island, not far from the airport. He did not believe that a duck would perch on a tree, and was sure his wife was wrong. Well, I'm here to tell you that his wife was absolutely right. There are a number of species of ducks and related waterfowl that perch and nest in the hollows of trees. One of these is the wood duck, with its colorful feathers, who nest in tree hollows more than a mile from water in the

woods. These birds are often seen perching in trees. The common goldeneye will also nest in tree hollows, and so will three species of mergansers.

One other "uncommon" bird behavior was seen and heard about three weeks ago. A friend who lives near the shore related an incident that occurred in her garden. A great blue heron had been hanging around her beach. These large herons are beautiful, with their blue-gray feathers and their long legs and neck. They're a pretty common sight in the summer, wading along the shores, hunting for small fish, amphibians, aquatic invertebrates, and reptiles to have for dinner. On this particular day, my friend heard a strange sound and sort of a shriek. Her daughter looked out and was horrified to see the great blue carrying off

a young eastern cottontail for dinner. This is not all that rare, as these large birds also have a taste for small mammals. Maybe this is not such a bad thing, as this meal seems to have discouraged the rabbits from being quite so bold in her garden. Who knows, maybe great blue herons are part of the solution to our rabbit population problem.

Trish Martin is a yeararound resident of Mackinac Island, has earned a master's degree in botany from Central Michigan University, and owns Bogan Lane Inn.

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