Grus is one of the gods of all the birds, including domestic, falconry and farm birds. The other gods include Aquila (god), Apus, Corvus, Cygnus, Pavo, Phoenix, Sagittarius (god) and Tucana.
Grus is a constellation in the night sky, hence why birds who die go to the Great Star in Sky. He is said to resemble a very large crane.
Grus' green earth! is similar to the Clan cats' when hedgehogs fly!