move and find suitable wetland environments. Information from tracked grey teal reveals that some flight movements were due to distant thunderstorms occurring. These thunderstorms were hundreds of kilometres away; however, due to their production of low-frequency sound, grey teal could detect this occurrence and move towards the source. Due to Australia being close to the equator, it can become very dry and hot in most places. Therefore, the use of these cues is essential for grey teal to find wetland habitats aiding their survival. Survival rates and life expectancy From a study completed by J.A. Mills on the morality and status of grey teal in New Zealand, approximate survival rates were established. To establish the rate of survival, the birds were banded. It was recorded that 68% of juveniles die within the first year of life, 77% by their first two years of life and then 85% by the end of their fourth year. Thus resulting in approximately 0.96 years of expected life for juveniles after they have been banded (age of 2–4 months). For grey teal that survive to one year of age, they are expected to have a further 2.9 years of life. For adults, the mean average was 50% of deaths annually, whereas for juveniles it was 68%. Similar results were shown in an Australian study where the mean average of deaths for adults was 52%, and for juveniles 66%. Therefore from the data collected, it can be assumed that the grey teal has an approximate life expectancy of between 2–4 years old. However, some exceptions occurred since the oldest adult recorded in the wild in New Zealand was 9 years old. It was 21 years old in Australia. Diet and foraging The grey teal has a diet mostly consisting of invertebrates from their habitat; these include larva of midges, water beetles, mosquitoes and caddisflies, as well as seeds from aquatic plants present in their habitat. Diet changes according to the locality and time of the year. Thus, in Australia grey teal feed mostly on plant material and especially seeds. It constitutes 87-97% of their diet. Although insects are eaten throughout the year, their part in the diet increases in spring. Similarly, molluscs and crustaceans are important in the diet only during spring and autumn. In Australia, the youngest ducklings feed only on insects but the relative amount decreases to only 30% when they are four weeks