Therefore, if we don't know the lay date and miss the hatch date, we can't determine the age of the chick. The trade-off is that murres and their auk relatives live a long time, perhaps 30 years or more. Unlike ourselves, female murres lay eggs up until the day that they die. A chick a year can add up to a lot over a lifetime of reproduction. A display of murre eggshells from Tatoosh Island.
Murres are monogamous, mainly because it takes two full-time parents to rear one chick.
Studies of other murre colonies have shown that individuals return to the same locales to greet their mates year after year. In fact, most murres return to the colony of their birth to pair off and begin adult life. Migrating Atlantic eels and Pacific salmon share the same behavior. Murres show several other forms of predictable behavior. For one thing, they're highly synchronous.