Evidence continues to mount that a highly controversial class of pesticides blamed for widespread bee declines is also harming other creatures, perhaps catastrophically.

In a study of neonicotinoid pesticides and bird populations in the Netherlands, biologists found a close and troubling link. As neonicotinoid levels rose in streams, lakes and wetlands, populations of insect-eating birds declined. The pesticides appear to have eliminated the insects on which they rely.

‘These insecticides appear to be having more profound effects than just killing our pollinating insects,” said ecologist Caspar Hallmann of Radboud University in the Netherlands, an author on the new study, published today in Nature.

Hallmann and his colleagues analyzed two long-term, Netherlands-wide datasets: one of bird counts, and the other of surface water measurements of imidacloprid, the most common neonicotinoid.

First introduced in the 1990s, neonicotinoids have become ubiquitous in agriculture and gardening, and in recent years have been identified as a cause of dramatic die-offs in domestic honeybees. They’re also likely contributing to widespread declines in wild bees and butterflies.

Effects on other creatures, though, were long thought to be minimal. Early toxicity tests suggested that risks to vertebrates were fairly small, and the compounds weren’t expected to accumulate in the environment at levels capable […]