Beaky Birds are common enemies that can be found in most levels.
Beaky Birds move toward the right of the screen, in a straight line. If one touches one of the player's Balloons, it will pop. However, Beaky Birds can useful at times, as you can walk on top of them when you don't have any Balloons, and this allows you to beat the first two stages without Balloons.
In the manual, Beaky Birds are put into the "Mischievous Enemy" category, and on page 11 it states as part of a joint description of Beaky Birds and Pokey Penguins:"In the air and on the ground, Pokey and Beaky will bring you down."