Each parent feeds the single chick for 2–3 days and then leaves for up to three weeks in search of food. These foraging trips can cover a distance of 1,500 km (930 mi) and mean the chick may be left unattended for over a week. When the chicks fledge they weigh around 900 g (2 lb), and may be heavier than their parents. In Tasmania, and especially on the muttonbird islands of the
Furneaux Group, the chicks are harvested at this time for food and oil. The largest population in the world (2.8 million pairs - about 12% of the species) seems to be located on
Babel Island. Adult birds foraging for food on the open ocean mistake plastic debris for food and then feed it to their chicks. This ingested plastic, as well as other factors, likely contribute to contamination of chicks. Thousands of Short-tailed shearwater fledglings are attracted to artificial lights during their maiden flights from nests to the open ocean. Fledglings are vulnerable to injury or death by collisions with human infrastructure and once grounded, to predation or becoming road casualties. ==Migration==