While most Canada geese go north to nest, some resident geese remain at Blackwater where the young broods may be seen in early summer. This flock of resident Canada geese began with injured adults who could not migrate and stayed to raise their families at Blackwater. However, the resident geese have multiplied and become pests that often destroy crops planted for the migratory waterfowl. There has been much speculation as to what causes the geese to begin their spring and fall migrations. The increasing or decreasing length of days, combined with weather conditions and other variables, motivate the geese to migrate twice yearly.
Fat deposits accumulate just prior to migration and provide energy for the long flight.
Older geese alternately share the lead position. Geese have been observed at altitudes of 29,000 feet, although the normal migration altitude is only 3,000 feet. Departure Most of the Canada geese wintering at Blackwater NWR and other areas of the Eastern Shore travel north in the spring. The flocks begin moving out in late February and most are gone by mid-March. From here they travel to their ancestral nesting grounds on the Ungava Peninsula near James Bay, Canada.