Birds keep their beaks open for a variety of reasons. The most common reasons birds gape, or keep their beaks open, are to cool down,beg for food, signal submission or aggression, and vocalize.
To Cool Down
One of the main reasons birds gape is to cool down. Since birds do not have sweat glands like humans, they must use other methods to regulate their body temperature. Opening their beaks allows birds to pant and release heat. This evaporation helps bring down their body temperature on hot days.
When a bird feels too hot, it will begin to breathe quickly with its mouth open. This rapid breathing, called gular fluttering, increases air flow over the moist tissues of the mouth and throat. As moisture evaporates from these surfaces, it takes heat with it and cools the bird down.
Scientists believe that the bare skin inside a bird’s mouth is full of blood vessels that act as a radiator. As blood circulates through these vessels, the moisture that evaporates from the mouth carries away excess heat and enables the bird to cool itself down. This is why overheated birds will often be seen panting with their mouths stretched wide.
Some birds also urohidrose, or excrete liquid droppings, at high temperatures. The evaporation of this liquid waste from the bird’s legs and feet can offer additional cooling power when a bird is hot. Urohidrosis combined with gaping gives overheated birds the maximum ability to dump excess internal heat into the environment.
To Beg for Food
Parent birds will deliberately gape and revealing their bright red mouths to stimulate their young to feed them. The nestlings tap the parent’s mouth in order to get them to regurgitate food. So gaping by parent birds is a way to entice their young to feed them so they can in turn feed their offspring.
Pet birds will also gape and expose their mouth when they want food from their owners. Parrots in particular will readily gape at their owners when they want to be hand-fed a treat. It’s an instinctual behavior meant to trigger a feeding response, similar to how baby birds tap their parent’s mouths.
To Signal Submission or Aggression
Gaping can also be a social signal among birds. Some species will gape to demonstrate submission to more dominant birds. Others will gape to show aggression during confrontations over resources or hierarchy.
Parrots, for example, will often expose their tongues during fights or squabbles over territory, food, or mates. This gaping behavior seems to demonstrate aggression or send a warning to potential rivals. In some parrot species, subordinate females will also gape and expose their tongues to dominant males as a sign of sexual receptiveness or submission.
Other types of birds like chickadees will gap their mouths open and closed repeatedly during disputes over rank or resources. Scientists think this gaping shows submission to the victorious bird and helps resolve the conflict peacefully. Similar gaping behaviors during aggressive encounters have been observed in songbirds, seabirds, and pigeons.
To Vocalize
Opening the beak also allows birds to vocalize. Calls, songs, and contact notes are all sounds birds make with an open mouth. The extent to which a bird gapes its beak will depend on the type of vocalization it is making.
Soft sounds like murmurs and whispers require little gaping. Louder alarm calls and flock communication sounds will cause a bird to open its beak wider. Complex songs and drawn-out contact calls often involve a bird stretching its beak open to its maximum gape.
Scientists have found that some birds even synchronize their gaping as they vocalize together. An oscine bird like a sparrow modulates the width of its beak when singing to optimize song resonances. Non-oscines like doves actually clap their open beaks shut repeatedly to make rhythmic cooing sounds.
So gaping allows birds not only to release heat and beg for food, but also to communicate important social signals for territory, bonding, and hierarchy. Next time you see a bird with its beak stretched open, look and listen for clues to understand why it is gaping.
Other Reasons Birds Gape
While cooling down, begging for food, signaling, and vocalizing are the most common reasons, there are some other possibilities for why a bird might gape:
- Yawning – Birds yawn just like humans and stretch their beaks open wide when doing so.
- Discomfort – Pain or illness can sometimes cause a bird to gap its mouth repeatedly.
- Resting – Birds will sometimes gape lightly while perching at rest.
- Nesting – Some species vocalize with gapes during nest construction.
- Bathing – Gaping often occurs during water baths to cool down.
When Gaping May Indicate a Health Problem
While gaping is most often a normal behavior for birds, chronic, excessive, or irregular gaping can potentially signal an underlying health issue. Here are some examples of when gaping may indicate a sick bird:
- Constant open mouth breathing without closing the beak
- Heavy breathing or loud raspy sounds when gaping
- Stretching the neck forward with the beak open
- Keeping the mouth open even in cool temperatures
- Twisting the head and neck into odd positions while gaping
Conditions that can cause birds to gape abnormally include:
- Overheating – Heat stroke causes rapid open-mouth breathing.
- Respiratory infections – Congestion obstructs normal breathing.
- Panting – Usually a sign of stress or fear in birds.
- Air sac or lung disease – Prevents normal oxygen exchange.
Birds suffering from these types of conditions may not fully close their mouths even at rest. They may also gag, stretch their necks, breathe with noise, or struggle for air while gaping. Any chronic open-mouth breathing in a bird warrants an exam by an avian veterinarian.
How Bird Beak Anatomy Facilitates Gaping
A bird’s unique beak anatomy allows it to stretch its mouth extra wide when gaping. Here are some key features that increase a bird’s gaping ability:
- Hinged jaws – A bird’s upper and lower beak are separate bones connected by a hinge, enabling them to open wider.
- Flexible skull – Birds have flexible skulls that can bend and bow outward as the beak opens.
- Malleable tongue – A bird’s tongue is thin, narrow, and adjustable, allowing room for air to pass over it.
- Wide gape – Gapes extend back beyond the head, increasing the size of the opening.
Many species also have genetic adaptations that increase their gaping ability for specific functions. Pelicans have huge gape sizes to scoop up fish. Woodcocks have movable nostrils that stay clear of their gaping beak when probing soil. Male frigatebirds inflate large throat pouches when displaying.
A flexible palate also allows birds to breathe through their nose while gaping. Parrots have especially maneuverable upper beaks adapted for mimicking speech. These specialized adaptations give birds the anatomical tools to gape effectively for different types of communication, thermoregulation, and foraging.
Gaping Width Varies by Species
While all birds can stretch their beaks open to some degree, gaping ability differs significantly across species. The width of a bird’s gape depends on factors like beak size, skull flexibility, neck length, and specialized respiratory structures.
Some groups like waterfowl and shorebirds have evolved extra wide gaping ability. Pelicans, for example, can gape their huge beak to over 10 inches wide. Other families like warblers and finches have smaller, narrower beaks suited for grasping insects and seeds, so they have less gaping ability.
The following table compares the gaping widths of selected bird species:
Bird | Gape Width |
---|---|
Pelican | Over 10 inches |
Hornbill | Around 4 inches |
Parrot | 1-3 inches |
Pigeon | Around 2 inches |
Finch | Under 1 inch |
Birds with wide gaping ability are able to dissipate more heat through panting, swallow larger prey items, and produce deeper, resonating vocalizations. Narrower gapes may constrain a bird’s thermoregulation, diet, and communication compared to birds with large gape widths.
Gaping Differs by Age
A bird’s gaping ability also changes as it matures. Baby birds gape instinctively to beg for food from their parents. Nestlings have wide, flexible mouths suited for swallowing regurgitated food.
As birds grow, their gaping becomes more controlled and intentional for functions like cooling and communication. Adult birds have rigid skulls less suited for nestling-style gaping. Older birds also have more precise muscular control over gaping width and mouth position.
However, fledglings still have underdeveloped respiratory systems and less precise gape control. So young birds often rely more on gaping for cooling compared to adults. Aging birds also have reduced gaping widths as beaks wear down and skulls become less flexible. So gaping behavior and ability both change across a bird’s life stages.
Why Do Birds Stop Gaping When Approached?
It is common for gaping birds to suddenly close their mouths when approached or looked at directly. There are several reasons birds stop gaping when they notice they are being watched:
- To avoid choking – Closing the mouth prevents choking if the bird must make a quick getaway.
- As a defense – A closed beak is safer in case of attack.
- Wariness – Attention from potential predators puts the bird on alert.
- Interruptions – Surprise or disturbances interrupt gaping behavior.
- Communication – A closed mouth signals feeling threatened or alarmed.
Birds that gape with their mouths wide open are vulnerable. So when something gets close enough to notice, their instinct is to close their beak to avoid choking or injury. Stopping gaping when approached also signals to predators that the bird is alert and ready to flee or fight.
How to Tell if a Gaping Bird is in Distress
In most cases, there is no need to intervene if you see a gaping bird. Normal gaping is not a sign of distress and birds close their mouths again once they cool down or finish vocalizing. However, here are some clues that a gaping bird may need help:
- Unable to close beak all the way
- Nostrils flaring with each breath
- Beak staying open when it should be closed
- Shaking, twitching, or odd head motions
- Rapid breathing without pausing
- Wheezing, coughing, or choking sounds
- Lethargy, weakness, or inability to perch
A bird experiencing any of these symptoms along with continuous gaping needs veterinary care right away. Without treatment, seriously distressed gaping birds can quickly succumb to heat stroke, injury, choking, or respiratory failure.
When to Call a Wildlife Rehabilitator
If you find a gaping bird that seems to be abandoned, injured, or unable to fly, here are some tips on when to call for help:
- Baby birds gaping frequently outside the nest may be orphans in need of care.
- Injured adult birds unable to close their beaks need rehabilitation.
- Gaping birds that cannot stand or perch require medical assistance.
- Birds gaping excessively paired with vocal distress calls need help.
- Gaping birds in dangerous locations like roads should be moved safely.
Use caution when approaching distressed gaping birds, as injured animals can lash out defensively. Use gloves, towels, and cages to safely contain injured birds until a wildlife rehabilitator can be reached.
Conclusion
Gaping is a natural and essential behavior for birds. By stretching their beaks wide, birds can cool themselves on hot days, beg for food from parents, communicate with other birds, and vocalize. Different species have evolved specialized gaping abilities to suit their environments and lifestyles.
While gaping usually does not indicate any trouble, chronic, excessive, or unusual gaping paired with signs of injury or illness may mean a bird needs help. With proper understanding, bird lovers can appreciate the amazing adaptations that make avian gaping possible while also recognizing when intervention may be needed.