There are two types of atomic bonds-ionic bonds and covalent bonds. They differ in their structure and properties. Covalent bonds consist of pairs of electrons shared by two atoms, and bind the atoms in a fixed orientation. Relatively high energies are required to break them (50â-â200 kcal/mol).
Hummingbirds fly by day when nectar sources such as flowers are more abundant. Flying low allows the birds to see, and stop at, food supplies along the way. They are also experts at using tail winds to help reach their destination faster and by consuming less energy and body fat. Research indicates a hummingbird can travel as much as 23 miles in one day.
When a hummingbird arrives at a flower it stops abruptly and hovers in front of it. It does this first by tilting its body at an angle of about 45 degrees. The wing-beat can now be back and forth instead of up and down. In most birds the up-stroke of the wing is just a recovery stroke to get the wing back into position for the next down-stroke.