Is organic food everything its advocates claim to be? A new study published in the Journal of the Science of Food and Agriculture describes an experiment in which the subjects were free from human biases. The authors found that wild birds preferred 'normal' bird food to the organic option.

To study this burning issue, the researchers set up pairs of identical bird feeders in over 30 locations around northern England. The feeders contained two types of the same variety of wheat seeds, one organic and one conventional. The researchers then monitored the rate at which each seed was eaten over the course of a few weeks.

It was found that the birds preferentially ate the conventional seeds. To make sure that there wasn't something about the relative placement of the feeders, the researchers switched each pair, and found that the birds learned the new location of the conventional seeds and continued to prefer eating from that feeder.

The experiment was repeated over a subsequent winter with a different type of seed, but produced the same results. More controlled laboratory trials with canaries found similar preferences for conventional over organic. In an attempt to explain this disparity, the researchers analyzed the seeds and found that the conventional seed contained upwards of 10 percent more protein per seed, most likely due to the use of inorganic nitrogen fertilizers used in conventional farming techniques.

Journal of the Science of Food and Agriculture, 2010. DOI: 10.1002/jsfa.4025 (About DOIs).