When the ostrich falls over, its egg is clearly visible at its feet. The shot then cuts to Mickey but when it cuts back to the ostrich getting up, the egg is missing.
Ostriches are African, not Australian. The Emu is a large, leggy, flightless bird, sometimes confused with the Ostrich, and Emus ARE Australian. But the cartoon clearly depicts an Ostrich, same as in Donald's Ostrich (1937). And BOTH birds live on grassy, treeless plains/Savanah, not in the jungle, as shown.
Despite being released in 1948, the opening title card shows a copyright date of 1941 (MCMXLI)