Skip to Content

Why Do Nuthatches Sweep?

Why Do Nuthatches Sweep?

Nuthatches are known for their unique behavior. Be it walking upside down or bill sweeping, they never fail to disappoint bird lovers. Have you ever wondered why nuthatches sweep? This article will explain the reasons behind nuthatch sweeping. Let’s dive in!

Do nuthatches sweep?

Nuthatches often rub their beak near their nests, side by side, creating a sweeping or brooming movement. It’s called bill sweeping. Most of the time, they showcase such behavior during breeding or nestling phases.

Check out this interesting video to see how they sweep.

Either or both of the partners can sweep with their beaks near the entrance of their nest. Also, they often hold a tertiary object in their beaks when creating the sweeping motion. Here is a list of objects nuthatches use when bill sweeping:

  • Insects: Most prominently, nuthatches are seen holding dead bodies of insects when bill sweeping.
  • Plants: Also, nuthatches hold plant material like bark, leaves, and gullible twigs when bill sweeping their nests.
  • Fur: Many nuthatches have been seen sweeping their nests with fur in their beaks as well.

Finally, it’s not always necessary for nuthatches to hold an object when sweeping. They often sweep with clean beaks around their nesting area.

Moving on, you might ask, why do nuthatches sweep? Let’s walk through all the reasons why nuthatches seem to sweep their nests!

Reasons why nuthatches sweep

The bill-sweeping behavior among nuthatches has intrigued the experts from the beginning. Many theories have been proposed to justify the bill-sweeping behavior among nuthatches. Let’s walk through a few of the reasons why nuthatches sweep.

1. Masking their scent

As we already discussed in the previous section, nuthatches hold various objects in their beaks during sweeping. These objects, like insects and plant parts, secrete various biological scents when squeezed. Nuthatches use the scent for their benefit during bill sweeping.

Nuthatches tightly hold these objects in their beaks and squeeze them during sweeping to expel the scents. When these birds sweep the objects at the entrance of their nests, they apply the chemicals near the nests to mask their scent. So, other birds cannot recognize their scent and pose no threat to the young ones residing inside.

2. Increasing their attachment to the roosting area

Another theory suggests that nuthatches sweep their nests to strengthen the bond between the partners. They know that their courtship behavior won’t increase during the breeding phase if an intruder threatens their nest. In such a scenario, their breeding won’t become successful and they cannot even become parents in the specific mating season. 

So, they use the famous bill sweeping technique to rub the scents of the insects near the opening of their nests. It can help them mask their scents to keep the invaders away and focus on courtship without disturbances to raise new lives.

3. Preventing squirrels

Like nuthatches, squirrels live in natural tree cavities. So, you can safely conclude that squirrels are potential competitors for nuthatches regarding tree cavities. However, squirrels are stronger contenders and can easily defeat nuthatches in a fight for tree cavities. Thus, nuthatches have developed a special ability to defeat squirrels for a tree hole. 

They rub various plant materials, fur, and insect bodies near the nest opening using the sweeping technique. The scent secreted keeps the squirrels away from the cavities. So, the nuthatch pair can raise their nestlings without worries.

4. Keep phytophagous insects and herbivores away

An attack of phytophagous insects can damage the trees where nuthatches live. Also, they can invade the private spaces of the bird family and create chaos. So, nuthatches should employ techniques to keep these insects and other herbivores away from invading their beloved nests. That’s when sweeping works!

A partner or both birds can sweep the nest entry with different objects. It gives off strong scents to phytophagous insects and other herbivores. Since they don’t prefer such odors, they stay away from nuthatch nest cavities, allowing the birds to raise their young ones peacefully.

5. Building nest entrance with mud, insect bodies, and saliva

Sometimes, nuthatches go beyond marking their nest entrances with biological scents through sweeping. They use the technique to build their nests. Some research suggests that a few nuthatch types, like the White-breasted nuthatch and Rock Nuthatch, use mud, saliva, and insect bodies to build their nests. Also, they often narrow down the nest opening by accumulating these materials near the opening.

So, these birds can use the bill sweeping technique to apply the layer of mud, insects, and their saliva near the nest entrance. It’s a defensive mechanism for keeping larger predators away from their nests and nestlings.

6. Cleaning their beaks

Nuthatches do not always use the sweeping technique to defend their nests or build their roosting area. There are more reasons why nuthatches sweep their beaks. During the nesting season, they stay near their young ones most of the time. They spend time feeding the nestlings and eating themselves. So, you can see them sweeping their beaks without holding anything near the nests.

They often clean their beaks by sweeping. Nuthatches love keeping themselves clean. When eating or feeding their young ones, insect tissues can stick inside their beaks and irritate the small creatures. So, they sweep their beaks near the nests to clean themselves and remove stuck particles from their bills.

7. Cleaning their nests

Another famous reason why nuthatches sweep is to clean their nests. Nuthatches keep their nests and nestlings clean and discard dirt particles from their nests. Often, unnecessary objects might get stuck near the mouth of the nests, including leaves, twigs, and dead insects.

The birds take their time to clean the nests and remove these particles by sweeping. They don’t hold anything in their beaks during sweeping and rub their bills to voluntarily remove stuck particles from their nests.


Nuthatch bill sweeping is a very interesting behavior, restricted to their various types. For ages, scientists have been trying to understand their unique bill-sweeping behavior. These birds have solid reasons to support their peculiar bill-sweeping habit. So, when you see a nuthatch pair sweeping the next time, you know the scientific reason behind their unique activity.