Birds and bees are something most of us take for granted as part of nature. The expression “teaching about the birds and the bees” to explain the process of human reproduction to young people is not an accidental expression. Bees and birds contribute to the essence of life on our planet. A study by the US Department of Agriculture estimated that “…perhaps one-third of our total diet is dependent, directly or indirectly, upon insect-pollinated plants.”

http://rachels-carson-of-today.blogspot.com.au/2012/07/death-of-birds-bees-across-america.html