Australian
Screen

Teacher’s notes

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This clip shows comb-crested jacanas rearing their young in a paperbark swamp in northern Australia. The early scenes show the male bird 'brooding’ three eggs in a small nest built on the top of floating lily pads. The following scenes show the female defending the male from other females. In the next scene the chicks have hatched and are exploring their watery world. In the final scene the male jacana is shown protecting his young, hiding them under his wings and striding away to safety. Narration and sounds of the swamp accompany the scenes.

Educational value points

• The footage reveals the physical features of the comb-crested jacana (Irediparra gallinacean), including the distinctive feature that gives it its name – a red fleshy forehead comb that varies in brightness according to the bird’s mood. Both genders are similar in appearance, but the female is a little larger, about 22 cm high, and slightly brighter in colour. The bird’s scientific classification is Phylum: Chordata, Class: Aves, Order: Charadriiformes, Family: Jacanida.

• Jacanas are also known as 'lotus birds’ or 'lily trotters’ because they use their long legs and extremely long toes and claws to spread their body weight over the floating vegetation and move delicately across its surface. From a distance they appear to walk on water and are therefore also known as 'Christ birds’. Jacanas spend most of their lives on this floating platform, hunting aquatic insects from it and raising their young on it.

• Jacanas are found in tropical and subtropical freshwater wetlands, including lagoons, billabongs, swamps, lakes, rivers and dams, providing there is adequate floating vegetation. They occupy coastal and subcoastal regions from the Kimberley in Western Australia, through northern Australia to around Grafton in New South Wales, but are more common in northerly parts of the range. They can also be found in New Guinea, Indonesia and the Philippines.

• Jjacanas’ nests are precarious and, in response to a mortality rate of up to 80 per cent for pre-hatched chicks, the species has evolved a strategy whereby the female mates with several males, which then build nests in her territory and incubate the eggs. Jacanas breed from September to May. In the Top End, shown here, they breed in April in the 'knock 'em down storm season’ or Banggerreng, one of six seasons in the Bininj–Mungguy people’s calendar.

• Jacanas use two gender-specific strategies to attempt to pass on their individual genes, and both are seen in the clip. The female patrols her territory and guards the males. If she is unsuccessful, males can be chased off before receiving a clutch or she might be replaced by another female that takes over all her males and kills all her eggs. The male deals with danger to the chicks by picking them up under specially shaped wings and carrying them off to safety.

• Known as a paperbark swamp because of the paperbark trees (Melaleuca leucadendron) often found in areas covered by water for many months, the freshwater lake or billabong shown in the clip is typical of those found in tropical parts of Australia. The billabong fills with water during the monsoonal or 'wet’ season from October to April and during the early months of the dry season. Paperbark swamps are popular habitats for jacanas and other birds.