Bird Food Source Alert: Declining Insects

In recent years, we've seen well-documented declines in domesticated honey bees, monarch butterflies, and other insects that attract a lot of attention. But we haven't really noticed the moths, beetles, and other insects that flitter and crawl through our everyday life. Birds, however, probably notice their decline a lot, since they're a major food source. 

A recent story in the journal Science documents a new set of data gathered mostly by amateur entomologists in western Europe. These folks have tracked insect abundance at more than 100 nature reserves since the 1980s, and the news is not good.

This group of amateurs, named the Krefeld Entomological Society (after their location in Germany) has seen the insect catches in their traps fluctuate every year. This is normal. But in 2013, they noticed that one of their longest-running sites showed a decline by mass of almost 80%. The numbers were just as low in 2014. In fact, the group found dramatic declines across more than a dozen other sites, even in reserves where plant diversity and abundance had improved. 

The group has installed more traps each year since 2013. They've also begun working with university-based researchers to look for correlations with weather, changes in vegetation, and other factors. Unfortunately, no simple cause for the decline has yet emerged.

If you don't like bugs, you're probably asking, "Why does this research matter?" The answer is that other creatures eat insects—such as birds. Dave Goulson, an ecologist at the University of Sussex in the United Kingdom, explains, "If you're an insect-eating bird living in that area, four-fifths of your food is gone in the last quarter-century." No matter what your opinion of bugs, this is important news.

No one knows what this research in western Europe means for insects elsewhere. But we at Talkin' Birds think that anything that affects the food chain for birds anywhere is worth investigating for the good of us all. 

A male hoverfly on a Bermuda Buttercup. (Photo: Wikimedia Commons; author: Alvesgaspar.)

A male hoverfly on a Bermuda Buttercup. (Photo: Wikimedia Commons; author: Alvesgaspar.)