Though the Kiwi is not one of the largest birds in the world, the kiwi definitely deserves a place in this list as it lays the largest egg with respective to the bird’s size. The egg is almost 20% of the bird’s weight! No one yet has understood as to why the kiwi lays such huge eggs. A species endemic to New Zealand the kiwi is a very shy and timid flightless bird and is known to live in deep burrows. They have other unique adaptations like short stout legs, hair like feathers and nostrils that help detect ᴘʀᴇʏ at the end of their long beak. These adaptations along with their capability to lay large eggs have made the kiwi quite famous internationally that New Zealanders are generally called as Kiwis.
Quite easily one of the largest flying birds with respect to wingspan, the trumpeter swan also lays huge eggs. The eggs of a trumpeter swan weigh as much as 350 grams and easily is the largest of all flying birds. The next largest egg must be that of Andean condor but that is almost 20% less heavy than that of the Swan’s. The trumpeter swan is found across North America. Swans are known to travel great distance to find suitable place to breed and the trumpeter is no different. They generally breed in the Eastern part of the continent. The trumpeter swan apart from being one of the heaviest flying birds are one of the most beautiful species too.
Cassowaries are third in this list, but they do belong to the same family as the ostrich and Emus and like them the cassowaries too lay huge eggs which are generally bright green or pale green-blue in color. The cassowaries are only found in the tropical rainforests of New Guinea and North eastern Australia. They are second heaviest birds in the world and third tallest next to ostrich and emu. Their ᴅɪᴇt consists of mainly fruits but they are omnivorous. A unique fact about cassowaries is that they are often quoted to be quite ᴅᴀɴɢᴇʀᴏᴜs to an extent that a ᴡᴏʀʟᴅ ᴡᴀʀ ᴛᴡᴏ ᴛʀᴏᴏᴘ stationed in New Guinea was ᴡᴀʀɴᴇᴅ about the species. The main reason for the concern is their powerful feet and claws. Each foot has three toes with the second/ middle toe armored with claws as long as five inches. Most of the cassowary ᴀᴛᴛᴀᴄᴋs are in self ᴅᴇꜰᴇɴsᴇ or against individuals who fed them asking for more. There has been one documented ᴅᴇᴀᴛʜ due to a cassowary where the bird had ᴘᴜɴᴄᴛᴜʀᴇᴅ the neck of a boy in self-ᴅᴇꜰᴇɴsᴇ. In spite of their ᴀɢɢʀᴇssɪᴠᴇ behavior they have not been very successful in survival and are considered enᴅᴀɴɢᴇʀed in most of their haʙɪᴛats. Attempts of breeding in captivity have not been so successful as the bird yearns for a tropical rain forest haʙɪᴛat. It is therefor essential that humans conserve the haʙɪᴛat of cassowary to prevent them from going ᴇxᴛɪɴᴄᴛ. The other large members of the Ostrich, emu and cassowary family like the rhea also lay huge eggs.
Emus are the second largest living birds in the world next only to Ostrich whose genes are related. This makes it clear that emus are also flightless birds. Emus are only found in Australia and they are present in the Country’s coat of arms too. The Emus can grow up to 1.9 mts in height and are present across Australia. Their powerful legs help them sprint as fast as 50 km/hr when needed. An interesting information about Emu is that during breeding season it is the female that fɪɢʜᴛs with other females for ᴍᴀᴛᴇs unlike most other species and the nesting duties are carried out by the males. Also, the female can nest two three times a year too if it is able to find partners. The eggs of an emu are quite that they weigh as much as 650 gms. The eggs of an Emu can remind one of Dragon eggs! They are dark green in color and can at times look quite shiny too. Emus of late are being reared domestically as their meat, leather and feathers are of great economical value. Their feathers may not be as beautiful as other birds, but they do fetch great price as they are extremely soft. Hence there are nations outside of Australia that rear Emus too.
No questions asked, the largest bird in the world lays the largest eggs too. The ostrich as most of you know is a flightless bird that calls Africa home. They are found in the arid and semi arid regions in the continent. They were once present in Asia Minor but were ʜᴜɴᴛed down to ᴇxᴛɪɴᴄᴛion in the region. The ostrich in the wild doesn’t have many ᴘʀᴇᴅᴀᴛᴏʀs as the few who could dare fear its powerful legs. Yes, the ostrich has one of the powerful pair of legs in the wild. They help the ostrich propel more than 13 feet in 1 stride and a kick can potentially ᴋɪʟʟ a human or even ᴘʀᴇᴅᴀᴛᴏʀs like lion. They generally do not go on ᴀᴛᴛᴀᴄᴋ mode as they primarily rely on seeds and leaves for food but can eat pretty much anything. They however get ᴀɢɢʀᴇssɪᴠᴇ if they feel ᴛʜʀᴇᴀᴛened or if any predator tries to steal its eggs. The ostrich lays the largest eggs of all extant birds in the world. The eggs weigh more than 1.4 kilos and are almost 13 centimeters wide and 15 centimeters long. The Guinness record for the largest egg by a living specimen, goes to an ostrich from a farm in Sweden owned by Kristan and Gᴜɴnar Sahlin and the egg weighed 2.5 kilos!