"Bird" was a slang term for 'good' in the 19th century and so a great shot on the Golf course became known as a 'bird', which then turned into 'birdie'. It was used for any under-par score at first. Then, 'eagle' was added to maintain the avian theme and it differentiated a shot of two under par, from the 'birdie', which was one under par. An extremely rare three under par shot is now called an 'albatross' (aka 'double eagle').
golf
An eagle is two strokes under par, a birdie is one stroke under. An eagle is a better score.
An Eagle in golf is lower than a birdie. A birdie is 1 stoke below par on the hole and an Eagle is 2 strokes below par For example, on a par four, an eagle is two strokes on a par three, an eagle is not used. it is just referred to as a hole in one!
Under par. Birdie, eagle or albatross.
I would think a double birdie would just be called an Eagle. Double Birdie is probably just golf slang for an Eagle, the much more common term. There is a Double Eagle though which is probably even more rare than a hole in one. That would be a score of a 2 on a par 5.
Since an eagle is bigger than a birdie I believe that's how it got its name. Even though an eagle is a lower score it is a much more valuable score.
Golf. Golf.
In golf, it is a birdie. In badminton, the birdie is officially called a "shuttlecock".
Golf
Either a par 3 and birdie 3 or an eagle 3 depends what par the hole is.
Eagle - +3 Birdie - +1 Par - 0 Bogie - -1 Double Bogie - -3
It's an eagle. 1 under par on a hole = birdie 2 under par on a hole = eagle 3 under par on a hole = double eagle