Woodpeckers:
- Woodpeckers are notorious for their distinctive "knock" or tapping sound. They frequently drum on trees to communicate with other woodpeckers, mark their territories, and search for insects and grubs.
Pileated Woodpeckers:
- Pileated woodpeckers are the largest woodpeckers found in North America. Their knocks are more profound and booming compared to smaller woodpecker species.
Ivory-billed Woodpeckers:
- This critically endangered woodpecker species, if it still exists, is renowned for its loud and resounding double knock.
Downy Woodpeckers:
- Downy woodpeckers produce rapid and high-pitched knocking sounds.
Hairy Woodpeckers:
- Hairy woodpeckers make loud, resonant knocking sounds similar to pileated woodpeckers but not quite as loud.
Ground-dwelling Birds:
- Some ground-dwelling birds, such as pheasants, may produce a soft knocking sound on the ground as they forage or build their nests.
Insects:
- Certain insect species, like deathwatch beetles, produce a knocking or tapping sound by striking their head or body against a hard surface. This distinctive knocking noise is how these insects communicate with one another.
Squirrels:
- Squirrels are known to produce a knocking or scratching noise when they chew nuts and seeds or scratch the bark of trees.
Rats and Mice:
- Rodents, such as rats and mice, may create knocking sounds inside walls or attics as they move around or gnaw on objects.
Large Land Animals:
- Some larger land animals, like hippopotamuses, may occasionally make a knocking or grunting sound during vocalizations or territorial disputes.