American Robins

1. American Robins • Robins are arriving earlier than before, often before the snow has even melted. They have to wait out the snow in order to eat and breed. • In Colorado, robins are migrating from low to high elevations where they breed two weeks earlier than they did in the 1970’s. (Tangley)

2. Mexican Jays • In southern Arizona, the breeding season of Mexican Jays is as much as 10 days earlier now than in the 1970’s. • The change correlates with higher spring temperatures, which rose nearly 4.5 F. (Tangley)

3. Red-Winged Blackbirds • Red-winged blackbirds are arriving at breeding grounds in Michigan nearly 20 days earlier than the 1960’s. (Tangley)

4. Prothonotary Warblers • These birds have been returning to breeding grounds in Virginia from South America and the Caribbean a day earlier for the past 20 years. (Tangley)

5. Loggerhead Sea Turtles • Loggerhead sea turtles are coming ashore to lay their eggs about 10 days earlier than 1989. • During this same time period, temperatures have increased by 1.5  F. • Warmer temperatures are also affecting the sex of sea turtles because the gender of these reptiles is determined by sand temperature. (Tangley)

6. Red Squirrels • Red squirrels are now bearing young about 18 days sooner • This makes it the first known mammal to be evolving its phenology in response to global warming (Tangley)

7. Oaks • Oaks are leafing out eight days earlier for every degree Celsius increase in temperature (Jensen)

8. Ash • Ash trees are only leafing half as fast as the oaks (Jensen) Back to Student 10 Home