Geese typically gather in large groups two times a year: when they are nesting and moulting. Nesting season begins in March when geese will pair up and choose a territory. From March through May, geese will be protecting their eggs and consequently become very aggressive. Additionally, geese moult out their flight feathers and grow new ones once a year, leaving them flightless for 4 to 6 weeks, from June to late July. Non-breeding adults will gather in large flocks and pick an area to remain for the remainder of their moult. Unfortunately, due to climate change in Canada, flocks of geese stay longer before migrating south, with some flocks migrating not very far at all.