Permanent Residents
Winter Residents and Visitants
It is interesting to note that the earliest arrivals in the spring are
the last to migrate in the fall. The reason is the food-supply. The
insectivorous birds arrive later and leave earlier than those that have
a more varied diet. An unusually severe winter sends birds south of
their usual winter range.
The dates of migration must necessarily vary with latitude. Migrants
arrive near Washington a week or two earlier than near New York City,
and near Boston a few days later. The lateness of the spring sometimes
causes a delay of a week or two. The May arrivals appear more nearly on
schedule. After May 15 birds begin to decrease in number, the "Transient
Visitors" passing farther north; by June 5 we have with us our
"Permanent Residents" and "Summer Residents."
In the fall the mildness of a season may cause November migrants to
remain into December, or an open winter may tempt those that habitually
migrate only a short distance to remain north of their usual winter
range.