In America, the drawing of bird-themed flourishes reached its peak in the last quarter of the 19th century, when the need for skilled scribers increased, so penmanship teachers - writing masters - began to advertise their services and compete for students. Penmen chose to create bird flourishes to advertise their skills because, due to their shape, birds represented (and still do) the perfect subjects motif to create graceful, harmonious and highly sophisticated flourishes to catch the eye of audiences. In addition, this was to prove their high skills and vast experience - even though the making of a bird flourish took them only 5 - 6 minutes, mastering this technique required long years of practice and probably thousands of repeated attempts until they could reach the level when it all seemed quite effortless.
Nowadays calligraphic design is mainly employed in digital graphic design, i.e., for designing of invitation cards, thank-you notes, diplomas, certificates and the like, and also in website design and digital art. By the way, drawings like this are often popular themes in tattoo art.