mike3241 wrote:Well, background research shows that there position is effected by like by the sun, or wind. But they gathered the info when these were not present
A clarifying point. As I read the paper by Dr. Begall, et al., environmental conditions (wind, sun, etc...) were still present, they attempted to account for them, however. It would be very difficult (if not impossible) to eliminate environment factors in non-laboratory settings, such as pasture. The proceedures described included field experiments where the environment can be measured. The satellite imagery (via Google Earth) doesn't allow direct measurement of the conditions to determine if they are present or not.
In this situation, the environment conditions are control variables. These are accounted for through a large sample size (in the paper, I believe it was several thousand individual animals) dispersed over many different location on the globe at many different times of day. By doing this, one would be able to make an assumption that the environmental conditions are random enough so as to not be a common factor in a North-South orientation of an observed animals. Any assumptions of this sort should be included and documented in the research paper.
If you do this experiment, ensure you have the time to analyze a large sample size. Additionally, I would expect that some individual animals in the images would exibit an orientation other than N-S. You must include these in your analysis as well to determine a percentage of observed animals aligned with Mag N and those that are otherwise. For example, if you made observations of 1000 animals and 800 exibit a N-S orientation and 200 were not, then, 80% exibited the expected behavior, alowing some logical conclusions to be drawn with respect to magnetoreception.
I hope this helps.
"As the circle of light increases, so does the circumference of darkness around it."
~ Albert Einstein