These scientists formed a hypothesis (the same one for several animal species); animals are sensitive to the Earth's magnetic field.
Based upon this hypothesis they developed an experiment with dogs.
For their experiment they did not record other factors that could contribute to a dog's orientation: visual stimuli, olfactory stimuli (wind direction), terrain, manmade structures (fences, land scraping, etc).
A means to exclude data that did not support their hypothesis was presented: dogs did not align to the magnetic field due to magnetic storms.
Their conclusion is dogs respond to the magnetic field like a compass except when magnetic storms confuse dogs. Do these same magnetic storms confuse a compass?
