Human landscaping affects avian flight, movement patterns

Researchers at the University of Missouri recently found that bird flight patterns and populations are affected by terrain and the presence of man-made structures on the ground. This information could lead to more effective bird habitat protection through the placement of forest corridors that enable dispersal.

Dylan Kesler, an assistant professor in the University's School of Natural Resources, said that individual movements impact many aspects of biology and behavior, including the intraspecies and interspecies interactions, population density, reproduction rates and gene flow of a species.

Kesler found that birds prefer to travel over forests because they offer increased protection from predators and easier access to resources. The presence of man-made structures such as roads and gaps between forests therefore restrict birds to certain areas.

Habitat fragmentation, the process of creating discontinuities in an organism's environment, threatens the survival of many species. Fragmentation leads to edge effects, changes in light, soil moisture and air temperature that alter the edges and sometimes the interior of an environment, making it inhospitable to its native residents.

When forests are disconnected, bird populations also become more isolated, leading to increased incidences of disease and inbreeding. This observation challenges the notion that birds are uninfluenced by deforestation and other human activities.

Kesler and graduate student Allison Cox studied the dispersal patterns of red-bellied woodpeckers, a non-migrating bird species. The researchers tagged a group of woodpeckers and tracked their daily flight patterns using GPS and radiotelemetry.

The researchers plan to observe the birds during the summer and fall as young birds establish territories and find mates during this time. They also plan to learn more about natal dispersal, the time it takes for a bird to fly to its breeding ground after birth, since for non-migrating bird species it is the only time individuals really migrate.

According to Kesler, for territorial bird species, natal dispersal is crucial to maintaining gene flow, avoiding inbreeding and maximizing population density.