Activation energy is the amount of energy required to initiate a chemical reaction. The activation energy can be determined from reaction rate constants at different temperatures by the equation. ln(k 2 /k 1) = E a /R x (1/T 1 - 1/T 2).
Robins also eat other small insects, berries, fallen fruits, and especially Rosaceae fruit in the fall and winter. Robins cannot digest hard fruits or grains, so they stick to soft fruits and organisms with softer skeletons (Howell, 1942). http://www.bio.davidson.edu/people/vecas...
Juvenile robins and eggs are preyed upon by squirrels, snakes, and some birds, such as blue jays, Steller's jay, common grackles, American crows, and common ravens. Adults are primarily taken by Accipiter hawks, cats, dogs, and larger snakes (especially rat snakes).