A DRAWING OF A BIRD THAT PECK ON A STICK

. Certain birds, particularly woodpeckers, engage in a specialized kind of pecking, using their beak to drill holes in trees in order to find insects under the bark. Woodpeckers also engage in a kind of pecking called drumming, a less-forceful type of pecking that serves to establish territory and attract mates.[ 2] Woodpeckers drum on various reverberatory structures on buildings such as gutters, downspouts, chimneys, vents and aluminium sheeting.[ 3]
The phrase, pecking order, referring to the hierarchical system of social organization was coined by Thorleif Schjelderup-Ebbe in 1921,[4] in reference to the expression of dominance in chickens by behaviors including pecking. Schjelderup-Ebbe noted in his 1924 German-language article that "defense and aggression in the hen is accomplished with the beak".[ 5] This emphasis on pecking led many subsequent studies on fowl behaviour to use it as a primary observation, however, it has been noted that roosters tend to leap and use their claws in conflicts.