Both studies focused on bug killers known as neonicotinoids (nee-oh-NIK-uh-tin-oydz). Earlier research showed these chemicals can harm honeybees and bumblebees. Both are important because they pollinate plants. That includes many that people eat. Now scientists are linking the chemicals to shrinking bird populations. Researchers don’t yet know what role the chemicals play. They may poison the birds or just deprive them of the insects they need to eat