A hermit thrush shows its spotted breast, eye-ring and cinnamon-colored tail. Photo by Roy Lukes.
I have been recording wild bird sightings in Door County for 50 years. Roy and I would lead a couple early morning bird trips each week of each summer for Ridges Sanctuary visitors from May to the end of July.
In order to see a greater variety of species, we car-pooled along back country roads to observe the native birds in various habitats. We sought and identified the nesting species as well as migrants that fly through the county to their far northern breeding grounds.
Roy knew of a few hidden wetlands where we would stop the cars, get out and listen. One of the best birds we heard was the American bittern, with its distinctive “unka-chunk” call from deep within the wooded swamp.
That wetland was partly filled when the land was sold and someone built a house nearby. The whole character of that woodland changed and the bitterns left.
The creatures that live in or use natural wetlands are so important in connection to the life of birds. Insects, small invertebrates and reptiles of these special habitats are food for nesting species and their young.
When the wet areas dry up it invites some predators to move in. These can be a great detriment to any nesting birds.
There has been an increase in homes being built in many areas of rural Door County, especially since the COVID-19 pandemic. Open fields are now dotted with houses and many areas have large expanses of fertilized, mowed lawns.
A large area of sterile mowed grass does not help feed any nesting birds. There is little natural food in these vast expanses of green, sometimes non-native grass, which is sprayed with poisons to kill weeds.
Thankfully, there are groups like the Door County Master Gardeners and Wild Ones who promote native vegetation that encourage the existence of native insects and flowering plants. We can also be grateful for the Door County Land Trust in their work to preserve many wild areas and native species.
A few years ago, I participated in a discussion of a film about the world’s bird populations for Earth Day. One feature that was highlighted was the huge areas in the Prairie Provinces of Canada, and perhaps in north central flatlands of the U.S. where rape seed is grown.
This plant is the source of canola oil, a widely used cooking ingredient. We learned that the seeds are treated with a chemical, a neonicotinoid, neonics for short, that kills insects and is absorbed by the plants.
Now they are finding it in the soil and water run-off in large parts of those planted fields. These chemicals kill insects that birds need to feed their nestlings. It is indiscriminate and destroys beneficial insects like bees and butterflies.
The warming climate is allowing the growing season to increase in length and move further north. This changes the breeding conditions of birds that used to nest where huge agricultural fields are now planted.
Over the years, a number of chemicals have been introduced into the environment before testing could be done. They were allowed to be used in agriculture and manufacturing for years while the effects on the natural world were gradually being discovered.
Remember the book, SILENT SPRING by Rachel Carson? It highlighted the terrible destruction of many birds through the use of DDT. That chemical weakened the shells of large birds like the bald eagle and many other fish-eating species so that when incubation began, the eggs shattered.
A warming climate permits invading insects to move further north, where they can harm native plants. The milder winters allow these new insects to survive instead of being frozen out of existence.
Birds that spend the winter in the tropics and migrate to our area are sometimes arriving after the masses of insect food, upon which they feed, have already emerged and diminished. These migratory birds arrive earlier and stay later. This reduces food availability and preferred nesting sites.
There are many drastic effects of our warming climate that impact nesting habitats and food sources. Warmer oceans create stronger hurricanes, decreasing valuable shoreline for nesting and migration habitats. A warming Arctic means a loss of ice that’s changing habitats for birds that breed there, causing die-offs.
