Natural History Wanderings

Smithsonian Science reported that invasive European earthworms (Lumbricus spp.) are responsible for the decline in Ovenbird (Seiurus aurocapilla) populations in the northern Midwest U.S. forests.

The earthworms consume leaf litter on the forest floor. This results in a decrease in the herbaceous plants that grow in the leaf litter and provide cover for the ground nesting birds. This makes the potential nest sites too visible to predators so the Overbirds reject the areas as potential nesting habitat.  The decreased leaf litter also reduces the number of bugs available for the Ovenbirds to eat.

Read more at Earthworms to blame for decline of Ovenbirds in northern Midwest forests, study reveals | Smithsonian Science.