The biggest living bird in the world is the ostrich.
Adult male ostriches can stand close to 9 feet (2.7 meters) tall, and exceptional individuals have been recorded weighing more than 340 pounds (150 kilograms).
That makes the ostrich both the tallest and heaviest bird alive today.
But “biggest bird” can mean several different things.
The bird with the largest wingspan is not the ostrich, and prehistoric birds existed that were much heavier than any living bird.
What Is the Biggest Bird in the World?
The ostrich, Struthio camelus, is the world's largest living bird.
It holds that title by overall combination of:
height;
body mass;
and total body size.
Guinness World Records reports that male ostriches have been recorded at up to approximately:
9 ft (2.74 m) tall;
345 lb (156.4 kg).
Most ostriches are smaller than those extreme records, but even an average adult remains enormous by bird standards.
Biggest Bird Records at a Glance
| Record | Bird | Approximate Record |
|---|---|---|
| Largest living bird | Ostrich | Up to about 2.74 m tall and 156 kg |
| Largest wingspan of a living bird | Wandering Albatross | Record 3.63 m |
| Heaviest living flying bird | Kori Bustard | Up to about 18.1 kg |
| Largest bird ever by mass | Giant elephant bird | Estimates exceeded 600 kg |
| One of the largest known flying birds | Argentavis | Wingspan over 6 m |
How Big Is an Ostrich?
Adult ostriches show noticeable differences between males and females.
San Diego Zoo gives typical adult sizes of approximately:
male: 6.9–9 ft (2.1–2.7 m) tall;
female: 5.7–6.2 ft (1.7–1.9 m) tall;
male weight: roughly 220–287 lb (100–130 kg);
female weight: roughly 198–242 lb (90–110 kg).
Record-sized males can exceed these typical weights.
Is an Ostrich Taller Than a Human?
Yes.
A large adult male ostrich can easily stand taller than an average adult human.
At close to 9 feet tall, a record-sized male can tower more than 3 feet above a person who is 6 feet tall.
Much of that height comes from the ostrich's exceptionally long:
neck;
legs;
and upright body posture.
Why Are Ostriches So Big?
Ostriches belong to a group of large flightless birds often referred to as ratites.
Living relatives and similar flightless groups include:
emus;
rheas;
cassowaries;
and kiwis.
Because ostriches no longer rely on powered flight, their bodies are not constrained by the extreme weight limitations faced by flying birds.
Instead, natural selection has produced a bird specialized for running across open ground.
Can the World's Biggest Bird Fly?
No.
Ostriches are completely flightless.
Their wings are relatively small compared with their body size, and the skeleton and chest muscles are not adapted to generate powered flight.
Instead of flying away from danger, an ostrich relies heavily on speed.
San Diego Zoo reports that ostriches can sprint in short bursts at approximately 43 mph (70 km/h).
Why Can Ostriches Run So Fast?
Ostriches have several adaptations for high-speed terrestrial movement:
very long legs;
large powerful leg muscles;
long running strides;
light distal limbs;
and only two toes on each foot.
No other living bird has the same combination of giant body size and extreme running specialization.
What Is the Second-Largest Bird in the World?
The emu is generally regarded as the second-largest living bird.
Adult emus can stand approximately 4.9–6.2 feet (1.5–1.9 m) tall and weigh roughly 66–121 pounds (30–55 kg).
They are native to Australia.
Even a large emu is substantially lighter than a large ostrich.
For a direct comparison, see our Ostrich vs. Emu guide.
What Is the Largest Flying Bird?
If “largest” means wingspan, the answer among living birds is the Wandering Albatross, Diomedea exulans.
Guinness World Records lists a male Wandering Albatross measured in 1965 with a wingspan of:
3.63 m (11 ft 11 in).
That is wider than many small cars are long.
The bird's extremely long, narrow wings are adapted for efficient soaring over the Southern Ocean.
Is the Wandering Albatross Bigger Than an Ostrich?
Not by overall body size.
The albatross has much larger functional wings, but its body is dramatically lighter than an ostrich.
So the two records describe different measurements:
Ostrich = largest overall living bird.
Wandering Albatross = largest wingspan among living bird species.
What Is the Heaviest Bird That Can Fly?
The Kori Bustard is generally recognized as the heaviest living bird capable of flight.
Exceptional individuals can weigh approximately 18.1 kg (40 lb).
Kori Bustards live in eastern and southern Africa.
Because flight becomes progressively more difficult as body mass increases, very heavy flying birds tend to spend much of their time on the ground.
Why Can't Birds as Heavy as Ostriches Fly?
Powered flight places severe physical demands on an animal.
As body mass increases, a bird needs:
more wing area;
more muscle power;
stronger bones;
and enough lift to keep its entire body airborne.
Beyond a certain point, a giant terrestrial body plan is simply incompatible with sustained powered flight.
Ostriches evolved in the opposite direction: larger bodies and powerful running legs rather than enormous flight muscles.
What Was the Biggest Bird Ever?
The largest known birds of all time were the giant elephant birds of Madagascar.
A 2018 anatomical analysis identified an enormous form named Vorombe titan.
Researchers estimated an average body mass of approximately 643 kg (1,417 lb), with the largest reconstructed individual potentially approaching 860 kg (1,896 lb).
That would make it several times heavier than the largest modern ostrich.
Was Vorombe Titan Really a Separate Species?
This part of the record now requires an important scientific caveat.
The 2018 study classified the largest elephant-bird bones as a separate genus and species, Vorombe titan.
However, genetic research published in 2023 analyzed ancient elephant-bird eggshell and questioned whether Vorombe was genetically distinct enough to deserve a separate genus.
The researchers suggested that the largest southern elephant birds may instead belong within Aepyornis maximus, perhaps with some skeletal differences reflecting sexual dimorphism.
So the safest modern wording is:
the largest known birds were giant Madagascar elephant birds, historically described in recent literature as Vorombe titan and/or very large Aepyornis.
How Big Were Elephant Birds?
The biggest elephant birds stood roughly 3 meters (almost 10 feet) tall.
They were similar to ostriches in being:
flightless;
long-legged;
large-bodied;
and members of the broader paleognath bird radiation.
But elephant birds were much more heavily built.
An enormous adult could have weighed several times as much as a modern ostrich.
When Did Elephant Birds Go Extinct?
Elephant birds survived on Madagascar until surprisingly recently in geological terms.
Current estimates place their disappearance roughly around the end of the first millennium to early second millennium CE.
Human activity, habitat change and hunting likely contributed to their decline, although the exact extinction process remains an active area of research.
What Was the Biggest Flying Bird Ever?
Several extinct birds were much larger in wingspan than any species alive today.
One of the most famous was Argentavis magnificens, an enormous bird that lived in South America millions of years ago.
Fossil evidence suggests a wingspan exceeding 6 meters (nearly 20 feet).
Another giant extinct seabird, Pelagornis sandersi, has also been reconstructed with an enormous wingspan exceeding 6 meters.
Because these birds are known from incomplete fossils and size estimates vary by reconstruction method, exact record claims should be treated as estimates rather than direct measurements.
What Bird Has the Largest Wingspan Today?
The record belongs to the Wandering Albatross.
The documented maximum of 3.63 m (11 ft 11 in) is the largest measured wingspan listed for any living bird species.
What Is the Largest Bird of Prey?
“Largest bird of prey” can also depend on the measurement used.
The Andean Condor is enormous by wingspan and body mass, although technically it is a New World vulture rather than an eagle.
Among living eagles, species such as the Steller's Sea Eagle are among the largest by mass.
For a dedicated comparison, see Largest Eagles in the World.
Does the Ostrich Lay the Largest Bird Egg?
Yes, among living birds.
An ostrich egg commonly weighs around 1.5 kg (3.3 lb).
San Diego Zoo notes that a single ostrich egg can weigh roughly as much as about two dozen chicken eggs.
However, relative to the female's enormous body size, the ostrich egg is not unusually large.
Did Elephant Birds Lay Bigger Eggs?
Yes.
Elephant-bird eggs were vastly larger than ostrich eggs.
Some reached more than 30 cm in length and may have weighed around 10 kg.
These are among the largest eggs known from any animal.
Why Is an Ostrich Still a Bird if It Cannot Fly?
Flight does not define birds.
Ostriches still possess the defining evolutionary and anatomical characteristics of birds, including:
feathers;
a beak;
egg laying;
a bird skeleton;
and descent from avian ancestors.
Many bird lineages have independently lost flight.
Other living flightless birds include:
emus;
cassowaries;
kiwis;
rheas;
and penguins.
FAQ
What is the biggest bird in the world?
The ostrich is the largest living bird. Adult males can approach 9 feet tall and exceptional individuals have exceeded 340 pounds.
What is the tallest bird in the world?
The ostrich is also the tallest living bird, with very large males reaching approximately 2.7 meters or 9 feet.
What is the heaviest bird alive?
The ostrich is the heaviest living bird.
What is the second-biggest bird?
The emu is generally considered the second-largest living bird.
What is the largest flying bird?
By wingspan, the Wandering Albatross is the largest living flying bird, with a documented maximum wingspan of 3.63 meters.
What is the heaviest bird that can fly?
The Kori Bustard is generally recognized as the heaviest living flying bird, with exceptional individuals reaching around 18 kg.
Was there ever a bird bigger than an ostrich?
Yes. Giant elephant birds from Madagascar were far heavier than ostriches and may have weighed more than 600 kg.
What was the largest bird ever?
The largest known birds by mass were giant Madagascar elephant birds. A 2018 study named the largest form Vorombe titan, although later genetic research has questioned that taxonomic distinction.
What bird has the largest wingspan?
The Wandering Albatross holds the record among living species, with a documented wingspan of 3.63 meters.
Can an ostrich fly?
No. Ostriches are completely flightless and instead rely on powerful legs that allow them to run at very high speeds.
Final Answer
The ostrich is the biggest living bird in the world.
Large males can stand about 9 feet tall and exceptional birds can weigh more than 340 pounds, making the ostrich both the tallest and heaviest bird alive today.
But it does not hold every bird-size record.
The Wandering Albatross has the largest wingspan of any living bird, while the Kori Bustard is among the heaviest birds capable of flight.
And if extinct species are included, giant elephant birds from Madagascar were far larger than ostriches, with reconstructed masses exceeding 600 kilograms.
So the simplest answer is:
largest living bird = ostrich; largest living wingspan = Wandering Albatross; largest bird ever by mass = giant elephant bird.
Related Reading
Sources Used for Fact Checking
Guinness World Records — Largest Bird Ever
Guinness World Records — Largest Wingspan of a Living Bird
San Diego Zoo Wildlife Alliance — Ostrich
San Diego Zoo Wildlife Alliance — Emu
Nature Communications — Elephant Bird Ancient DNA Research
