Parents continue to keep close watch on their chicks for about a month and the chicks leave the nest after about two months. This can take much longer, however, if the parents have not been able to supply them with enough food. Going to sea is the most hazardous time of a fledgling's life - only about half the birds that go out for the first time return home. At this stage they remain at sea for many months and only return home for their first moult. Young penguins continue to stay out at sea for long periods, sometimes travelling great distances. Only in their 3rd to 4th years do they come back to their homes to mate for the first time.