Shoebills rarely raise more than one chick, but will hatch more. More rarely, the species has been seen foraging in rice fields and flooded plantations. When prey is spotted, it launches a quick violent strike. However, they are still fed for possibly a month or more after this. Preferred prey species have reportedly included marbled lungfish (Protopterus aethiopicus) and Senegal bichir (Polypterus senegalus) and various Tilapia species and catfish, the latter mainly in the genus Clarias. "Observations on nesting of shoebill Balaeniceps rex and wattled crane Bugeranus carunculatus in Malagarasi wetlands, western Tanzania".  Microscopic analysis of eggshell structure by Konstantin Mikhailov in 1995 found that the eggshells of shoebills closely resembled those of other Pelecaniformes in having a covering of thick microglobular material over the crystalline shells.  When they are first born, shoebills have a more modestly-sized bill, which is initially silvery-grey. Many humans are not much taller than five feet, so shoebills are definitely large birds! They are quite sensitive to human disturbance and may abandon their nests if flushed by humans. The wing to tail size cannot be used for identification; it is similar to those of several other birds.  BirdLife International has classified it as Vulnerable with the main threats being habitat destruction, disturbance and hunting. Exceptionally for a bird this large, the shoebill often stands and perch… Fish eaten by this species are commonly in the range of 15 to 50 cm (5.9 to 19.7 in) long and weigh around 500 g (1.1 lb), though lungfish of as much as 1 m (3.3 ft) have been attacked. The dark coloured legs are fairly long, with a tarsus length of 21.7 to 25.5 cm (8.5 to 10.0 in). 13 (1): 39–50. Also unusual, its tail is the same colour as its wings. , The shoebill was known to both ancient Egyptians and Arabs, but was not classified until the 19th century, after skins and eventually live specimens were brought to Europe. "Distribution and Conservation of the Shoebill (Balaeniceps Rex) in the Southern Sudan".  The shoebill is non-migratory with limited seasonal movements due to habitat changes, food availability and disturbance by humans. Around 60% of strikes yield prey. Other prey eaten by this species has included frogs, water snakes, Nile monitors (Varanus niloticus) and baby crocodiles. The younger chicks eventually die and are intended as "back-ups" in case the eldest chick dies or is weak. Exceptionally for a bird this large, the shoebill often stands and perches on floating vegetation, making them appear somewhat like a giant jacana, although the similarly sized and occasionally sympatric Goliath heron (Ardea goliath) is also known to stand on aquatic vegetation. The wings are broad, with a wing chord length of 58.8 to 78 cm (23.1 to 30.7 in), and well-adapted to soaring.  Long flights of the shoebill are rare, and only a few flights beyond its minimum foraging distance of 20 m (66 ft) have been recorded. While hunting, the shoebill strides very slowly and is frequently motionless.  The signature feature of the species is its huge, bulbous bill, which is straw-coloured with erratic greyish markings. "IUCN Red List of Threatened Species: Shoebill", "Dictionary entry for the Latin word "balaena, "The phylogenetic affinities of the Shoebill (, "A phylogenomic study of birds reveals their evolutionary history", "Sahara - Algeria - Rock Art in Oued Derat and the Tefedest Region", "Challenges and successes in the propagation of the Shoebill Balaeniceps rex: with detailed observations from Tampa's Lowry Park Zoo, Florida". When flushed, shoebills usually try to fly no more than 100 to 500 m (330 to 1,640 ft). They are a little bit taller and even have bigger beaks than their female counterparts. The genus name comes from the Latin words balaena "whale", and caput "head", abbreviated to -ceps in compound words. Male shoebills are bigger in weight, height, and bill size than females. The nest itself is about 1 to 1.7 m (3.3 to 5.6 ft) wide. doi:10.1111/j.1748-1090.2012.00186.x. These eggs measure 80 to 90 mm (3.1 to 3.5 in) high by 56 to 61 mm (2.2 to 2.4 in) and weigh around 164 g (5.8 oz). The beak of a shoebill can be 24 centimeters long and 20 centimeters wide. 132 (1): 69–82. So far, two fossil relatives of the shoebill have been described: Goliathia from the early Oligocene of Egypt and Paludavis from the Early Miocene of the same country.