Migration

All About Birds

Bird Migration

Multiple Select

Why do birds migrate? (select all that may apply)

• Day Length

• Food Resources

• Nesting sites

• Weather

• Inherited biology

Why do birds migrate?

• Birds migrate to move from areas of low or decreasing resources to areas of high or increasing resources.

• The two primary resources being sought are food and nesting locations.

Types of Migration

• Permanent Resident

• Short-Distance Migrants

• Medium-Distance Migrants

• Long-Distance Migrants

Multiple Choice

_______ do not migrate. They are able to find adequate supplies of food year-round.

• Permanent Residents

• Long-Distance Migrants

• Short-Distance Migrants

• Medium-Distance Migrants

Multiple Choice

________ move only a short distance, as from higher to lower elevations on a mountainside.

• Permanent Residents

• Long-Distance Migrants

• Short-Distance Migrants

• Medium-Distance Migrants

Multiple Choice

_______ cover distances that span from one to several states.

• Permanent Residents

• Long-Distance Migrants

• Short-Distance Migrants

• Medium-Distance Migrants

Multiple Choice

_______ typically move from breeding ranges in the United States and Canada to wintering grounds in Central and South America.

• Permanent Residents

• Long-Distance Migrants

• Short-Distance Migrants

• Medium-Distance Migrants

Origins Of Long-Distance Migration

• Seasonal change is one of the most dependable features of our planet, providing predictable resources such as spring leaf-out, monsoon rains, insect hatches, and fruiting seasons.

• One leading theory holds that avian migration evolved by a gradual extension of smaller annual movements as birds searched for improved food or breeding opportunities.

•  Individuals whose movements gave them better chances to survive and reproduce passed that migratory behavior along to their offspring.

• A key force in this evolution may have been the earth’s many cycles of environmental change, including the melting and retreat of vast ice sheets about 15,000 years ago. Migrants retreated to more southern breeding localities and made shorter migrations while the ice ruled the north. When ice retreated the migrants moved north to take advantage of renewed breeding opportunities in the unoccupied habitat that emerged.

Poll

Did Migration Originate From The North Or The South? (select one)

What Triggers Migration?

• day length

• lower temperatures

• changes in food supplies

• genetic predisposition

Day Length and Temprature

• Longer days in the spring and summer mean higher abundance of insects, vegetations, and fruit.

•  Escaping the cold is a motivating factor but many species, including hummingbirds, can withstand freezing temperatures as long as an adequate supply of food is available.

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Yearly Migration Trend

Where are the Ducks?

How do birds navigate?

• Birds can get compass information from the sun, the stars, and by sensing the earth’s magnetic field.

• They also get information from the position of the setting sun and from landmarks seen during the day.

• Some species, particularly waterfowl and cranes, follow preferred pathways on their annual migrations. These pathways are often related to important stopover locations that provide food supplies critical to the birds’ survival.

Open Ended

Name one landmark you use to navigate back to your house from the school.

How Do Birds Navigate?

• After tracing the migration routes of all these species, we concluded that a combination of geographic features and atmospheric conditions influence the choice of routes used during spring and fall migration