Page:The Migration of Birds - Thomas A Coward - 1912.pdf/39

Rh many weeks, but when, as often happens, the mast crop fails, they become nomadic, and pass from place to place in their hunt for food. They visit fields top—dressed with manure, glean the refuse of the harvest, frequent the farmyards, and in early spring, visit the budding larches to prey upon their insect pests. On the other hand golden plovers and lapwings are remarkably local in their winter habits, and so long as the weather remains open will frequent the same fields throughout the Winter. Severe weather, especially snow, which effectually closes their chance of obtaining food, at once drives them away. They will migrate to the unfrozen mud-flats of the coast, or to those parts of England, generally the south—west, and Ireland, where the climate is normally milder, or they will even leave our islands altogether under great stress.

The wandering habit. except during the breeding season, is confirmed in most birds, and experience shows that the same species of birds visit the same districts again and again when there is some particular food supply to attract them. Memory and experience guide them from place to place. This regular visitation of certain food bases, being of the greatest importance to birds which have a long period of travel or wandering before them, tends to originate the so-called route by which they travel. The fact that as a rule these stages are in consecutive steps