Herbivorous birds, also known as vegetarian birds, are avian species whose primary diet consists of plant matter rather than meat. There are many types of herbivorous birds in the world, ranging greatly in size from small songbirds to massive flightless species. In this article, we will explore some of the largest herbivorous birds on Earth.
Ostriches
One of the largest and most well-known herbivorous birds are ostriches. Ostriches are flightless birds native to Africa that can stand up to 9 feet tall and weigh over 300 pounds. Ostriches have long, thick, and powerful legs that allow them to run at speeds up to 43 miles per hour. They have long necks and small heads with large eyes. Ostriches feed on a variety of plant material including leaves, seeds, grasses, and flowers. Their large size allows them to eat coarse vegetation that other herbivorous birds cannot digest.
Emus
Emus are the second largest living birds after ostriches. Emus are flightless like ostriches and are native to Australia. They can reach up to 6 feet tall and weigh over 100 pounds. Emus have long necks and legs with soft gray-brown plumage. They can run at speeds up to 30 miles per hour using their strong legs. Emus utilize their sharp beaks to forage for seeds, fruits, buds, tender shoots, and insects. However, the majority of their diet consists of grasses and herbs. Their size allows them to consume a wide variety of vegetation.
Southern Cassowaries
The southern cassowary is the third largest living bird and the largest in the cassowary family. Native to New Guinea and northeastern Australia, cassowaries can stand up to 6 feet tall and weigh up to 130 pounds. They have black plumage with bright blue necks and red pouches on their throats called wattles. Cassowaries have a distinct helmet or crest on top of their heads made up of keratin. They use their powerful legs and feet to forage through dense rainforest vegetation looking for fallen fruit and buds. Cassowaries swallow seeds and nuts whole to be disseminated throughout the rainforests in their dung.
Emus vs Ostriches
Since emus and ostriches are the two largest herbivorous birds, it can be useful to directly compare them:
Feature | Emus | Ostriches |
---|---|---|
Average Height | 5-6 feet | 6-9 feet |
Average Weight | 90-105 lbs | 220-350 lbs |
Native Habitat | Australia | Africa |
Maximum Running Speed | 30 mph | 43 mph |
Diet | Seeds, fruits, buds, shoots, some insects | Leaves, seeds, grasses, flowers |
As shown in the table, ostriches are larger, taller, and faster than emus. However, they occupy different habitats and have slightly different diets. Both utilize their large size and speed to efficiently find and digest coarse vegetation.
Herbivorous Bird Benefits
Large herbivorous birds like ostriches, emus, and cassowaries provide important benefits to their ecosystems:
- Help disperse seeds and propagate vegetation through their dung
- Control insect populations
- Aerate soil with their scratching
- Provide food sources for predators
- Unique wildlife for ecotourism
However, some large herbivorous birds like emus and cassowaries can also damage agricultural crops and rangelands. Their size and speed make them difficult to control or deter. Overall though, most large herbivorous birds play important roles in maintaining biodiversity and ecological health.
Other Large Herbivorous Birds
While ostriches, emus, and cassowaries are the largest, there are many other big herbivorous birds including:
Rheas
Rheas are large, flightless birds native to South America. They can reach 5 feet tall and weigh over 60 pounds. There are two species – the greater rhea and the lesser rhea.
Elephant Birds
Elephant birds were giant, flightless birds that inhabited Madagascar until going extinct in the 17th century. The largest elephant bird, Aepyornis maximus, stood over 10 feet tall and weighed over 1,000 pounds.
Moas
Moas were giant flightless birds native to New Zealand. They went extinct in the 15th century after overhunting by humans. The largest moa, Dinornis maximus, reached 12 feet tall and weighed over 500 pounds.
Tinamous
Tinamous are stocky, ground-dwelling birds found in Central and South America. They are one of the largest families of bird able to fly, with some species reaching almost 2 feet long and over 2 pounds heavy.
Conclusion
Ostriches, emus, and cassowaries are considered the three largest living herbivorous birds. Ostriches stand out as the tallest and heaviest of them all. However, emus and cassowaries also grow quite large and utilize their size and speed to consume coarse vegetation. Throughout history, there have been many giant herbivorous birds, but human activity led to their extinction. Large herbivorous birds fill important niches in their ecosystems by dispersing seeds, aerating soil, controlling insects, and providing food sources.