This video from the USA is called Cornfield Ants, Lasius alienus, Social Behavior and Dispersal.
Translated from Stichting Bargerveen in the Netherlands:
Jan 28, 2016 – In the Netherlands cornfield ants are very rare inhabitants of calcareous grasslands. Last summer, the species was found by employees of Foundation Bargerveen on the Sint-Pietersberg [Mount Saint Peter; mountain near Maastricht]. Is the modification of vegetation by mowing and grazing here now bearing fruit?
The cornfield ant (Lasius alienus) is a very rare species in South Limburg. Until 2004, the species was only known from the Bemelerberg hill. During research into the effects of grazing in the Popelmondedal valley, the southern slope of Mount St. Peter in Maastricht in 2015 by Stichting Bargerveen effects on ants were also examined. Great was the surprise when during the identifications of the catches this winter several cornfield ants were found. This species was totally absent in the intensive monitoring of the Popelmondedal in 2006 and except for an unconfirmed catch from 2012 this typical calcareous grassland species had never been previously reported from Mount St. Peter.