Pregnancy: Diagnostic Tests. The list of diagnostic tests mentioned in various sources as used in the diagnosis of Pregnancy includes: Urine human chorionic gonadotropin (HCG) tests - these are the basis of home pregnancy tests.
Eagles (and most large birds) fly by soaring; it's much more energy efficient than flapping their wings. We do use the technique for our own flights. The reason eagles and other soaring birds do this rather than flap is that they generally hunt from the air and so spend a lot of time waiting for prey. They don't need to go anywhere specific and don't need to move fast until they spot prey. Until then they want to use as little energy as possible.
Pairs of bald eagles have been seen whirling through the air with talons locked together. This could be a form of courtship or a ritualized battle between an intruding eagle and one defending its territory. Whichever it is, eagles do not actually copulate in the air. Copulation usually takes place on a branch near the nest or on the ground. On rare occasions, bald eagles have remained locked together by their talons long enough to fall to the ground. I received an email telling of two talon locked eagles falling into a bush beside a person's home.