|
Robins |
Ruby-Throated
Hummingbirds |
Spring
migration patterns and timing |
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Main
factors that prompt them to migrate |
*
Availability of food
* "Good" weather
(Daylength plays small role.) |
*
Daylength (photoperiod) |
Main
winter food |
Fruits
from trees and shrubs |
Flower
nectar, (sap), insects |
Main
breeding season food |
Earthworms,
bugs, insects, other ground-dwellers |
Flower
nectar, (sap), insects |
How
do they know their migration route? |
No single
route. Depends on where food is and on weather. Babies learn to "hang
out" with other robins and learn from older ones. |
Babies
have innate, instinctive knowledge of route. They make the trip alone. |
Ability
to survive cold temperatures |
Can
survive in colder temperatures than hummingbirds can. |
Can't
survive in extremely cold temperatures. |
Average
weekly temperature when they arrive in your neighborhood. |
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|
Migration
speed. How many miles per day can they fly? |
Average
38 miles per day. |
Average
20 miles per day. (But fly up to 500 miles in 20 hours when crossing
Gulf of Mexico.) |
How
high do they fly? |
1,500
to 3,000 feet high |
Just
above trees (or waves in the Gulf) |
Possible
migration
hazards |
Snow
and ice storms (from early migration), predators, collisions |
Bad
weather during long (500-mile) flight over the Gulf of Mexico, collisions |