Seasonal foods and Aboriginal astronomy

Aboriginal and Torres Strait Islander people pay close attention to the positions of the stars to determine seasonal change. This informs them about the behaviours of plants and animals that are used for food and medicine.

Seasonal foods and nutrition

Aboriginal and Torres Strait Islander people carefully observe the positions of stars in the sky to predict seasonal change, which is linked to the behaviour of plants and animals. In Australia, many plants used for food or medicines are seasonal, so it is critical for people to know how the plants, animals, weather, and stars are interconnected. In this lesson plan, we will examine a seasonal food source that is found across Australia: the emu egg. We will focus on Kamilaroi and Euahlayi traditions from northern NSW.

Case study - the Celestial Emu

The Celestial Emu is an Aboriginal constellation shared by many communities across Australia. In Kamilaroi and Euahlayi traditions of northern NSW, the Celestial Emu is made up of the dark spaces in the Milky Way between the Coalsack Nebula (next to the Southern Cross) - which is the emu’s head – down to the body in the Western constellations of Scorpius and Sagittarius. The legs extend down through the constellations of Ophiuchus and Aquila (Fig. 1).¹ The position of the emu in the sky after sunset throughout the year informs people about the bird’s behaviour, including when it lays eggs. The representation of the emu in the sky can change throughout the year, depending on where it is positioned in the sky at dusk.²

Fig. 1 The Celestial Emu seen in the dark bands of the Milky Way. Image: Ray Norris, Barnaby Norris.

The Celestial Emu (called Gawarrgrgy in the Kamilaroi and Euahlayi languages) links to the breeding cycle of the terrestrial emu (called Dinawan). When it rises in the sky at dusk in April and May (Fig. 2A), it signals the start of the emu breeding season. At this time, the celestial emu is perceived as a female running as she chases a male to mate. Once they mate, the male sits on the nest and incubates the eggs. This is the best time to harvest emu eggs for food.

In June and July, the Celestial Emu begins to shift so it appears horizontal high in the sky at dusk. By June, most eggs have chick embryos in them, so the people stop collecting them for food. At this time, the Celestial Emu is seen as a male sitting on the nest. Come August and September, the emu in the Milky Way is vertical to the horizon at dusk, with the emu’s head pointing downward. The people now see the male emu getting up from the nest as the chicks hatch, which the males then rear and care for. Later in the year, the Celestial Emu shifts around, and is seen sitting in waterholes in the sky.

Fig. 2 The changing perspective of the Celestial Emu through the year, each connected to a particular aspect of an overall dreaming narrative connected to the lifecycle of the terrestrial emu and its link to ceremony. (A) April-May, when the female terrestrial emu chase males and pairing up for mating. (B) June-July, when the male emus are sitting on the nest. (C) August, when the chicks begin hatching. (D) Oct-Nov, when it is seen ‘sitting in the billabong’ encouraging the summer rains. Image: Ghillar Michael Anderson and Robert Fuller (Journal of Astronomical History and Heritage), reproduced with permission.

Emu eggs

Emus (Dromaiusnovaehollandiae) lay about 10-15 eggs per year, and incubation lasts ~55 days³. About half of the clutch leads to fully fledged chicks. During nesting, males sit on the nest 24/7 and aggressively defends it. Because of this, Aboriginal people use teamwork to collect the eggs. The people use an Emu Caller, a special device that looks like a miniature didgeridoo and mimics the sound of an emu⁴. People hide, and one person taps the device with the palm of their hand, making the emu-like sound⁵. This draws the male away from the nest, as he seeks to find and fight-off the phantom emu. Another person then runs to collect a few of the eggs, leaving enough behind so as to ensure a sustainable population.

Emu eggs are highly nutritious. They are rich in both monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA)⁶. An emu egg is quite large, weighing between 400 and 650 grams. This is roughly equivalent to a dozen chicken eggs. They contain about 30% saturated and 70% unsaturated fats (totalling ~360 calories/1506 kJ) and contain all eight essential amino acids. They are high in protein (~24 g), equalling 96 calories (402 kJ). They are comparatively low in carbohydrates, having only ~4 g of carbs, totalling 16 calories (67 kJ). Therefore, an entire emu egg contains approximately 475 calories (1987 kJ).

Classroom activity - Health and Physical Education Years 5 and 6

In these classroom activities students will explore the times of the year emu eggs are available for collecting and eating based on the position of the Milky Way at dusk. Students will examine the nutritional value of emu eggs and estimate how many people a single emu egg can feed, and how this relates to nutritional standards of The Australian Guide to Healthy Eating.

Curriculum connections

This resource addresses the following content description from the Australian Curriculum:

• Investigate the role of preventive health in promoting and maintaining health, safety and wellbeing for individuals and their communities (ACPPS058)

This resource addresses the following excerpts from the achievement standard for Years 5 and 6 in Health and Physical Education:

• describe their own and others’ contributions to health, physical activity, safety and wellbeing
• examine how physical activity, celebrating diversity and connecting to the environment support community wellbeing and cultural understanding

Inquiry-based learning questions

• How important are emu eggs as food to Aboriginal people?
• How do Aboriginal and Torres Strait Islander people observe the positions of stars to tell them about seasonal change?
• What is the nutritional value of emu eggs?
• How to they contribute to healthy eating?

Activity 1 – Examining the role of star positions and seasonal change

Suggested timing for activity: 30-45 minutes, including class discussion

Required resources: computer, paper, notebook.

Students can use the free computer software program Stellarium⁷ to explore the positions of the celestial emu in the sky when it rises at sunset throughout the year, and how this relates to the behaviour patterns of emus on the land.

1. Watch the short video on the Emu in the Sky by Ben Flick⁸: https://www.youtube.com/watch?v=LzFYFutiwoA
2. Download and open the Stellarium program: https://stellarium.org
3. Set the date to the beginning of March, and move the time to just after sunset.
4. Find the Emu in the Sky.
5. Gradually move the date forward, keeping the time to just after sunset. How is the celestial emu changing over time?
6. What does the emu look like in April? June? August?
7. Discuss how can this signal the behaviour patterns of the terrestrial emu?

Activity 2 – Estimating nutritional value of emu eggs

Suggested timing for activity: 30-45 minutes, including class discussion

Required resources: Computer, handout, calculator, pen and paper.

Students should examine the nutritional value of emu eggs collected during a hunt, and estimate how many people they could feed based on their caloric value, and the values of fat, carbohydrates, and other nutrients.

1. Students should go online to research how many eggs an emu will lay in a single clutch. Recommended website: https://australianmuseum.net.au/learn/animals/birds/emu/
2. From this, students can take a guess at how many eggs can be collected from a single hunt (keeping in mind that some should be left in place to ensure a sustainable population, and that not all eggs will hatch viable chicks).
3. With their guess, students can then estimate the total number of calories from the combined eggs.
4. Calculate the number of people this can feed, using the guidelines from The Australian Guide to Healthy Eating for a single meal⁹
5. Examine how the nutritional value of the eggs used for healthy eating by Aboriginal people might differ from those specified in the Guidelines, and discuss reasons for this.