Eight Reasons Why Birds Have Their Mouth Open

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There are many activities that birds perform every day to ensure their survival and the continued survival of their species. One of these behaviors is mouth opening. You may be wondering the reasons for why birds have their mouths open.

Birds may have their mouth open to vocalize or communicate, eat, drink, cool their body temperature, collect and use nesting materials, to defend against predators or intruders, or they may have their mouths open due to fatigue, illness, or stress. 

Birds may open their mouth when they need to call or sing, or when they are hungry or thirsty. They need to open their mouth to take in food and water but it can also happen because they are scared or need to cool down or grab and manipulate an object.

Read on to learn more reasons why birds open their mouths and how it helps their survival.

TIP: If you want to check out the best pair of binoculars for bird watching, we recommend a pair of waterproof and fog-proof 8 x 42 binoculars like the Celestron – Outland X 8×42 Binoculars (Amazon link).

Why Do Birds Have Their Mouth Open?

Why Do Birds Have Their Mouth Open?
Why Do Birds Have Their Mouth Open?

Birds open their mouths by opening their beaks. The beak is a bony structure covered in keratin. It is made of two structures, an upper and lower beak. The upper part is the premaxillary bone and the bottom part of the beak is the mandible. There are many reasons for a bird to open its mouth. These are discussed in more detail below.

1. Opening The Mouth To Vocalize And Communicate

Birds open their mouths to make to vocalize. They may chirp, whistle, or sing for a variety of reasons. Much of bird communication is by sound. 

Even a mother bird returning to a nest with food will give a distinctive call to her chicks as a signal for them to open their beaks so they can receive the food. The baby birds will also open their mouths and make a particular begging sound that triggers the mother bird to place food inside their open mouths.

The begging of chicks is reinforced in some species by special markings inside the chick’s beaks. These markings seem to serve as a target for the parent bird when it is delivering food.

Bird song often functions in courtship but can also function as a form of territory defense. In the spring in the United States, Red-winged Blackbird males will establish a territory and sing from an exposed perch while fluffing up their feathers. 

This serves to attract nearby females and, at the same time, also warns other males that this is a claimed territory. Since these blackbirds are polygamous, it is important that the male can attract many females. 

He also has bright red patches on his wings that are accentuated during his song and courtship behavior.

2. Opening The Mouth To Eat 

In order to eat, a bird needs to open its mouth by opening its beak. The type of beak a bird has depends on what type of food the bird is adapted to eat. 

For instance, insect eaters have narrow, pointed beaks, while seed eaters have short, conical-shaped beaks. Birds that eat insects can stab prey with their sharp beaks. 

Seed eaters need to be able to crack seeds, and the size of the seed the bird can eat varies by the size of the beak and the mouth. 

Some species are also able to use their beak along with their feet to hold food while they eat. This is common in parrots but is also seen in mousebirds. A mousebird will sometimes grab a piece of fruit with its foot and bite pieces off.

Other species are specialized feeders. For instance, the flamingo holds its beak upside down, opens the jaws and moves the head side to side to filter out small crustaceans from the water.

3. Opening The Mouth To Drink

Birds need to drink water every day, so this is also when they open their beaks. A thirsty bird will often dip its beak in the water and tilt its head backward to swallow. Some aerial birds, such as swifts and swallows, will fly low over a dam or river and scoop water up in their mouths as they skim over the water.

4. Opening The Mouth To Cool Down

Animals have evolved different methods to cool the body. Most of us have seen a dog panting when it is hot, but in birds, a different process occurs.

Gular flutter is the process that birds use to cool down when they are hot. Birds are able to draw in the air over the moist area of the mouth while performing a fluttering action of the throat. This gular flutter works well to cool the body down and is especially important on very hot days.

Birds do not have any sweat glands and rely on air moving over the throat and respiratory system to help cool the body down.

5. Opening The Mouth To Collect And Manipulate Nesting Material

Birds can use their beaks to grab objects. While sometimes this is a food item, other times, the beak is used to collect and hold nesting material. Nest complexity varies depending on the species with birds like doves and pigeons making simple nests made out of twigs which they pick up and carry in their beaks.

Other bird species are able to use their beaks to weave intricate nests. For instance, the weaver birds of Africa are able to open their mouths and strip a long leaf from a tree. They then carry this to their nesting site where they will proceed to manipulate the leaf with their beak and legs in order to make a nest.  

The tailorbird is able to sew two pieces of leaves together to make its nest. The bird uses its beak to accomplish this. 

6. Opening The Mouth To Attack A Predator Or Intruder

Birds respond in various ways to the presence of an intruder in their territory. The type of response usually changes according to the type of intruder. A robin that gets too close to a dove’s nest or chicks may find itself being slapped by the dove’s wings and also pecked. 

An owl in a tree may be divebombed by other birds. These birds may open their mouths and use their beaks to peck at the owl, eventually chasing the bird away. Similarly, an African Harrier Hawk may be attacked by A Fork-tailed Drongo that mobs the hawk and tries to peck it on the back. 

It is usually specific species of birds that use their beaks to mob and attack birds of prey that pose a threat to them and their chicks. In Africa and parts of Asia, Drongos are the species often observed harassing and attacking hawks and even eagles. In the United States, it is common to see Red-winged Blackbirds attacking hawks.

7. Opening The Mouth Because Of Fatigue

A bird that is tired may open its mouth to yawn. This is normal and nothing to be worried about if you see your pet bird doing this on occasion. However, a bird that constantly opens its mouth and acts differently may be ill. 

TIP: A bird bath is necessary to attract birds on your backyard. There are a lot of options on how and where to place a bird bath. Check out my picks on different bird baths below (Amazon links):
Free-standing Bird Bath
Hanging Bird Bath
Deck Mounted Bird Bath

8. Opening The Mouth Because Of An Illness Or Stress

A sick bird may open its mouth often. This can happen especially if the bird has a respiratory infection, but other illnesses may also make the bird open its beak to get more oxygen. It may also be that the bird is stressed. 

A bird that is under stress, for instance, after being chased by a predator, may keep its mouth open for a while as it recovers from the fear and stress. 

What Does It Mean When a Bird Has Its Mouth Open?

A bird could open its mouth for several reasons. It could be preparing to vocalize, eat, drink, or try to cool down. It may also depend on the mood of the bird and if it needs to manipulate some object, like nesting material. 

Do Birds Open Their Mouths When Scared?

Yes, birds do sometimes open their mouths when scared. This behavior may be combined with alarm sounds or calls. In some species, the bird may also puff up the body to appear larger while opening the beak and emitting a hissing sound. 

Why Does My Bird Open His Mouth When I Pet Him?

Why Does My Bird Open His Mouth When I Pet Him?
Why Does My Bird Open His Mouth When I Pet Him?

There are a few reasons why a pet bird may open its mouth when you pet it. It can be a sign of contentment, but it can be because its angry. If a bird is being aggressive, it is likely to open its mouth and bite or attempt to bite you. 

In some parrots, the birds open their beaks slightly at night and grinds the beak. This is actually a sign of contentment that you can see and hear with birds like cockatiels. It means the bird is happy and resting peacefully.


Birds may open their mouths for many reasons. It can be for communication where the bird is calling, singing, or producing an alarm call. The beak needs to be opened for the bird to eat and to drink. 

Birds thermoregulate differently from other animals; they cool down by opening their mouth and engaging in gular flutter. Finally, the beak can be used to grab and manipulate objects, such as nesting material.

My Favourite Equipment for Bird Watching

Bird watching is one of the least expensive hobbies out there, but you still need some equipment to get the most out of it. 

The essential equipment to start bird watching is a pair of binoculars. My preference is 8 X 42 binoculars. The number 8 is how much the magnification is, while 42 is the field of view in millimeters of the lenses.

A pair of waterproof and fog-proof 8 x 42 binoculars like the Celestron – Outland X 8×42 Binoculars on Amazon is an excellent choice for both beginners and experts. 

In time, you can choose more expensive models and also opt to buy a spotting scope like the Celestron Ultima 80 on Amazon.

These are a lot more expensive compared with binoculars though, so if you are only a beginner, start with binoculars first. A spotting scope is only helpful for birds far away, such as out on a pond or seashore.

There are a few rules or guidelines you should abide by as an ethical birder. These are listed below.

  • Do not enter private lands without prior permission from landowners.
  • Follow all the rules in refuges and reserves, including cleaning up any garbage from your campsite.
  • Do not disturb birds on nests.
  • Do not use apps and play songs to call up birds when they are hungry, tired, and breeding during spring and summer.

Rae Osborn

Rae Osborn is an avid bird watcher and holds a doctorate in Biology. Her interests in birds began as a child growing up in South Africa. She has continued to study birds and has bird watched in the United States and South Africa.

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