Evey, et al., we just had 175 +/- Sandhill cranes fly (low!) over our yard in the Redlands on an azimuth directly toward Delta. I saw no waiting for thermals or any of that nonsense. ;-)
Oops! Another 140+ are inbound, and these are in fact using thermals off of the south wall of our little mesa.
On 09 Dec 2003, we had 750 +/- fly by here, consisting of many flocks, and during most years we’ve had flyby flocks throughout December, so my guess is that they are still coming...