01-11-2013, 03:03 PM
a) Some birds stay year round.
b) Some birds leave your area completely.
c) Some birds come to your area as their "south" for the winter.
d) Some birds fly long distances to migrate.
e) Some birds gradually shift south as conditions require it (e.g., lakes freeze, food sources diminish).
The robins and jays are probably best described as a mix of "a" "c" "e."
Robins, for example, change their habits. In winter, they flock up, move into sheltered thickets and eat a of dried fruit. They may move south, they may not, but they don't fly to South America or anything dramatic. When the ground thaws, they spread back out into the open to look for worms. Your robins visible now may actually breed to the north.
b) Some birds leave your area completely.
c) Some birds come to your area as their "south" for the winter.
d) Some birds fly long distances to migrate.
e) Some birds gradually shift south as conditions require it (e.g., lakes freeze, food sources diminish).
The robins and jays are probably best described as a mix of "a" "c" "e."
Robins, for example, change their habits. In winter, they flock up, move into sheltered thickets and eat a of dried fruit. They may move south, they may not, but they don't fly to South America or anything dramatic. When the ground thaws, they spread back out into the open to look for worms. Your robins visible now may actually breed to the north.