Since 2009, wetland birds, coastal birds, and grassland birds have increased in numbers, while aridland birds, eastern forest birds, and western forest birds have declined. So says a report from the North American Bird Initiative. The changes are shown in the first chart at right, and discussed in the bullet points below. The second chart at right shows the trends over time.
(For larger view, click on chart.)
- Wetland bird indicators increased more than 15%, continuing an uneven trend that began around 1995.
- Coastal birds increased roughly 8%. Here the trend is split, however.
Migratory shore birds have been in decline since 1985, and that trend continues. These birds use our coastal areas as part of long migrations between Canada and the Caribbean or South America. Winter coastal species, however, have been gradually increasing since about 1998. These birds spend the winter in our coastal regions, then migrate northward during the summer.
- The small increase in grassland birds reverses a long decline that started in the early 1970s.
- The trends for inland birds (non-coastal) are shown in the second chart at right.
- Aridland birds decreased the most, more than 5% since 2009. This continues a decline that has been occurring since at least 1970.
- Eastern forest birds and Western forest birds also declined, both continuing trends going back to 1970.
- Three categories of birds have declined more than 30% since 1970: aridland birds, grassland birds, and eastern forest birds.
Where birds are on the rebound, the report attributes it to successful conservation efforts to restore essential habitat. Where birds continue to decline, it is because habitat continues to be lost. The map at right shows the continental United States, and the colors match the habitats used in the report. Light green is eastern forest, light yellow is grassland. Missouri is primarily grassland and eastern forest. Previous posts in this blog focused on threatened species (here), land use in Missouri (here), on the fragmentation of forestland in Missouri (here), and on urban sprawl (here).
Why do birds matter? Why do people count them? First of all, some people love them. Beyond that, however, have you ever heard the saying “The canary in the coal mine?” Do you know what it means? Coal miners face many deadly dangers. Among them is the undetected seepage of poisonous gas into the mine. In olden days, they didn’t have fancy electronic detectors to warn them. Instead, they took a canary in a cage down into the mine. If suddenly the bird died, it meant that poisonous gas was building up in the mine.
Bird counts serve a similar purpose. If their numbers decline, it warns us that essential habitat is being lost, that the earth’s capacity to support life is being eroded, that we need to take action to prevent a greater disaster from occurring.
The report contains no information specific to Missouri beyond what can be read from the map shown above. One important habitat that does not show up well on the map is inland wetland. Missouri sits on the Mississippi Flyway, one of the most important paths for migrating birds (shown in a second map at right.) During the spring, the birds travel up the Mississippi River from the Gulf Coast. They continue up the Mississippi, or they branch out along the Ohio, Missouri, and Illinois Rivers. Some go as far as northern Alaska. During the fall, they return the way they came.
Don’t think of these birds as using only the major rivers. Think of them using Missouri’s forests, fields, lakes and streams as feeding stations and stopover points on their long, long journey. Nearly half of North America’s bird species, and about 40% of its waterfowl, spend at least part of their lives in the Mississippi Flyway.
North American Bird Conservation Initiative, U.S. Committee. 2014. The State of the Birds 2014 Report. U.S. Department of Interior, Washington, D.C.
Texas Parks and Wildlife Deptartment. Map of Mississippi Flyway, Downloaded 11/23/14 from http://www.tpwd.state.tx.us/huntwild/wild/birding/migration/flyways/mississippi.
Audubon Society, Mississippi Flyway, http://conservation.audubon.org/mississippi-flyway.