Resources
Understanding Migration at Beamer
Figure 1
Raptors use thermals to move across the landscape efficiently, by rising on hot air, then gliding until they find the next thermal. The thermals get more productive throughout the day, so the birds get higher on the mid-day thermals, and potentially get high enough to exceed the typical human’s visual range!
Figure 2
Cool air settles on Lake Ontario overnight, creating cooler air breezes that hit the Niagara Escarpment most days. Prevailing southerly or westerly winds from the Jetstream push warmer air towards the lake, and the two meet along the Niagara Escarpment. Combined with warm air rising off the rocky cliffs and other ambient thermal activity, these all combine to create a long line of rising air, which runs the length of the Escarpment. Some days when there is little thermal activity, the updraft along the ridge is still present, and raptors follow this, a bit like a surfer follows a wave, efficiently moving north each spring towards their breeding grounds.
Figure 3