Editing Common loon (section)

== Longevity and terminal investment ==
Considerable information on longevity and survival rates has been collected in the past two decades, owing to the implementation of an efficient capture protocol that permits marking and monitoring of large study populations.<ref>{{Cite book|title=A replicable capture method for adult and juvenile common loons on their nesting lakes. In: 1992 Conference on the Loon and Its Ecosystem|last=Evers|first=David|publisher=North American Loon Fund|year=1993|location=Meredith, NH, USA}}</ref> A rough preliminary analysis showed that common loons of both sexes survive at an annual rate of over 90% until they reach their mid-20s,<ref name=":11" /> but show a survival rate of only about 75% thereafter. However, a second, finer-scaled analysis made clear that male loons begin to show higher mortality, increased territory loss and lower body condition starting at age 15.<ref name=piper2018/> Perhaps in response to their physical decline, males 15 and older show increased rates of both territorial aggression and territorial vocalization. This age-related shift in behaviour is interpreted as terminal investment, a "go for broke" strategy seen in senescing animals that are attempting to eke out another year or two of breeding before they die.<ref name=piper2018/>