The change happened in the last few hours, as noted by MacGeneration. This is an increase in shipping times of approximately one month. Apple began shipments of the shipments of the machine to Europe in mid-January. At the time, Apple reported one-month dispatch. The change today widens the availability gap to roughly two months.
Currently, the US and Canadian stores still report a March timeframe. The discrepancy may be due to the fact that the Mac Pro is assembled in the United States, therefore making supply easier. However, as availability tightens globally with no signs of , it is possible that the US store will follow up with similar delays in the future.
Update: April in the U.S. now too:
