10.3.3 To estimate the direction of the food source:
1. Focus on the orientation of the waggle-runs in relation to the gravity-axis.
2. Video tape dance behaviour under diffuse light conditions to avoid changes in dance orientation due variation in light intensity (Edrich, 1975).
This is because when you compare dances performed at different times of the day, you need to account for the changes in the sun’s azimuth. To estimate the direction of the advertised foraging site measure first the average angles of 4 waggle-runs by using a radial protractor over the screen. Such average angle was added to the sun azimuth angle at the solar time when the dance was captured. The sun azimuth angle for each dance can be calculated using the world-wide web (e.g. http://aa.usno.navy.mil/data/docs/AltAz.php#formb).
The foraging sites exploited at a social scale can be estimated by a systematic recording of the dance orientation in the whole colony. If video recordings are made systematically, this parameter is especially useful for analysing collective honey bee foraging under natural conditions.