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Dryad

Results of Common Loon territory monitoring (1979–2009) and of chick monitoring surveys (2004–2006) at Voyageurs National Park

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Jul 24, 2023 version files 59.09 KB

Abstract

Recovering species are not returning to the same environments or communities from which they disappeared. Conservation researchers and practitioners are thus faced with additional challenges in ensuring species resilience in these rapidly changing ecosystems. Assessing the resilience of species in these novel systems can still be guided by species’ ecology, including knowledge of their population size, life history traits, and behavioral adaptations, as well as the type, strength, and number of ways that they interact with other species in the community. We summarized broad trends of Common Loons (Gavia immer) breeding at Voyageurs National Park during 1973–2009 and evaluated the effects of increased risk from recovering Bald Eagles (Haliaeetus leucocephalus) on chick survival during 2004–2006. Adult Common Loons appear to have increased over time. Using Bayesian survival models that accounted for imperfect detection of unmarked individuals, we determined that chick survival of Common Loons was high from year to year and was unrelated to predation risk from Bald Eagles as chicks in territories closer to active nests did not experience greater mortality than those further away. We suggest that Common Loon chicks were unaffected by the recovery of this top predator during the three years of sampling. Previous research indicates that Bald Eagles and other predators are an important source of egg losses, but Common Loons can compensate by re–nesting. Despite current uncertainties from anthropogenic threats, knowledge of a species’ ecology remains instrumental in determining their resilience during recovery.