Egg embryo is adequately developed it hatches, i.e. breaks out of the egg's shell. Some embryos have a temporary egg tooth they use to crack, pip, or break the eggshell or covering. The largest recorded egg is from a whale shark, and was in size. Whale shark eggs typically hatch within the mother. At and up to , the ostrich egg is the largest egg of any living bird, though the extinct elephant bird and some dinosaurs laid larger eggs. The bee hummingbird produces the smallest known bird egg, which weighs half of a gram (around 0.02 oz). Some eggs laid
White-collared swift White-collared swift The white-collared swift ("Streptoprocne zonaris") is a resident breeding bird from central Mexico, the Greater Antilles and Trinidad south to Peru, northern Argentina and southeastern Brazil. This very large swift builds a saucer nest of mud, moss and chitin on a ledge in a cave, usually behind a waterfall, and lays two white eggs between March and July. It breeds in the mountains and foothills, but forages over a much larger area, including lowlands. White-collared swift is a massive and powerful species, long, and weighing . It is the largest species of swift in its range except in