Data from: Managing individual nests promotes population recovery of a top predator

Threatened species are managed using diverse conservation tactics
implemented at multiple scales ranging from protecting individuals, to
populations, to entire species. Individual protection strives to promote
recovery at the population- or species-level, although this is seldom
evaluated. After decades of widespread declines, bald eagles, Haliaeetus
leucocephalus, are recovering throughout their range due to legal
protection and pesticide bans. However, like other raptors, their recovery
remains threatened by human activities. Bald eagle nests are commonly
managed using buffer zones to minimize human disturbance, but the benefits
of this practice remain unquantified. Within Voyageurs National Park
(VNP), Minnesota, USA, managers have monitored bald eagle populations for
over 40 years, and since 1991, have protected at-risk nests from human
disturbance using buffer zones (200 and 400 m radius). We aimed to (1)
quantify the recovery of bald eagles in VNP (1973–2016), and (2) provide a
first-ever evaluation of the individual- and population-level effects of
managing individual nests. To do so, we developed Bayesian Integrated
Population Models combining observations of nest occupancy and
reproductive output (metrics commonly collected for raptors) to estimate
nest-level probabilities of occupancy, nest success, and high productivity
(producing ≥2 nestlings), as well as population-level estimates of
abundance and growth. The breeding population of bald eagles at VNP
increased steadily from <10 pairs in the late 1970s to 48 pairs by
2016. At the nest-level, management significantly improved occupancy and
success. At the population-level, management led to 8% and 13% increases
in nest success and productivity rates, respectively, resulting in a 37%
increase in breeding pair abundance. Synthesis and applications. There is
a clear need to evaluate how management approaches at multiple scales
assist in species recovery. Our study uses an Integrated Population Model
to reveal the population-level benefits of a widely used, individual-based
management action (protecting nests using buffer zones) on a recovering
raptor.