Earthworms Cause Ovenbird Decline

A recent paper in Landscape Ecology confirms that ovenbirds are found in lower densities in sugar maple and basswood forests in Wisconsin where invasive earthworms are found.

Ovenbird numbers have been in decline for decades in the Northeast and Midwest. Habitat loss is typically named as the chief culprit, although non-native earthworms were known to be a contributing factor.

Ovenbirds are a ground-nesting, forest-interior species. They rely both on large tracts of forested land and plenty of leaf-litter from which to build their beehive-oven-shaped nests. Earthworms, which are not native to the northern parts of the United States, quickly chew up fallen leaves and other forest debris, leaving the ovenbirds with few places to hide and little to build with.

Read the paper in Landscape Ecology, here. (Fee or subscription required.)
Read the Smithsonian Institution blog post on the findings, here.

The Smithsonian information has been reprinted widely around the web. A quick survey showed only verbatim copies of the blog post, but the coverage does appear to be widespread.

Photo: Ovenbird, courtesy of the Wisconsin Department of Natural Resources


One thought on “Earthworms Cause Ovenbird Decline

  1. Hopefully some extremely species-specific virus can be engineered to wipe out all these invasive worms. Though there is some solace in knowing that invasive-species worms might have gotten some nutrition from all the hundreds of invasive-species cats that I had to shoot and bury — to completely rid my land of every last wildlife-annihilating cat. My land has been 100% cat-free for two years now, all the native species are starting to return, much to my relief. NO cats return once you get rid of them all. Well worth the effort of only 2 seasons of shooting cats with inexpensive .22s. At least that’s a very species-specific method, and one that most everyone has in their homes to combat the cat problem today, not a decade from now. A method that actually works. One that is actually faster than their breeding rates or ability to out-adapt to traps. A solution that solves ALL problems that that particular invasive-species causes.

    Though I wouldn’t worry about Ovenbirds not having nesting material in my woods. I have some very healthy woods and the loam is deep! I have a large amount of dead-fall as well, as the forest is making a transition from softwoods to hardwoods. I make sure to leave all dead-fall where it lies. (Adding further reward for my mushroom hunting.) This also provides nest spots and safe dens for a myriad of species that use log-falls and dead-woods for safe habitat. For example, my woods are rich in Pileated Woodpeckers as well. A good indicator-species of the health of any woods. (2 of them seem to enjoy checking out their reflections in my vehicles’ mirrors and windows most every day, year-round. I think they’re naturally vain. :-) ) Further attesting to the health of my woodland floor; Trilliums, Solomons, & Jack-In-The-Pulpits are plentiful. I’ve probably cataloged no less than 20 fern species too.

    I found the best way to manage a forest is to leave it alone — after you have removed all the invasive-species that is. Cats being the absolute worst invasive-species of all. They had annihilated the whole food-chain in my woods. I was surprised how quickly things recovered after all the hundreds of cats were shot and buried. Owls, hawks, gray-fox, and all other native predators are returning in decent numbers now that their food sources are no longer being destroyed by cats. As well as all the other ground-nesting birds like Wild Turkeys, Grouse, etc. 4 adult turkey toms were in my yard just yesterday.

    The perfect solution for invasive-species cats is in every gun made — now get working on a species-specific virus for those worms!

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