DOI: 10.5061/dryad.j6f4858
title: Data from: Top-down effects of repatriating bald eagles hinder jointly recovering competitors

description: 1. The recovery of piscivorous birds around the world is touted as one of
 the great conservation successes of the 21st century, but for some
 species, this success was short-lived. Bald eagles, ospreys, and great
 blue herons began repatriating Voyageurs National Park, USA, in the
 mid-20th century. However, after 1990, only eagles continued their
 recovery, while osprey and heron recovery failed for unknown reasons. 2.
 We aimed to evaluate whether top-down effects of bald eagles, and
 bottom-up effects of inclement weather, habitat quality, and fish
 resources contributed to the failed recovery of ospreys and herons in a
 protected area. 3. We quantified the relative influence of top-down and
 bottom-up factors on nest colonization, persistence (i.e., nest reuse) and
 success for ospreys, and occurrence and size of heronries using 26 years
 (1986-2012) of spatially-explicit monitoring data coupled with
 multi-response hierarchical models and Bayesian variable selection
 approaches. 4. Bald eagles were previously shown to recover faster due to
 intensive nest protection and management. Increased numbers of eagles were
 associated with a reduction in the numbers of osprey nests, their nesting
 success, and heronry size; while higher local densities of nesting eagles
 deterred heronries nearby. We found little evidence of bottom-up
 limitations on the failed recovery of herons and ospreys. 5. We present a
 conservation conundrum: bald eagles are top predators and a flagship
 species of conservation that have benefited from intensive protection, but
 this likely hindered the recovery of ospreys and herons. Returning top
 predators, or rewilding, is widely promoted as a conservation strategy for
 top-down ecosystem recovery, but managing top predators in isolation of
 jointly recovering species can halt or reverse ecosystem recovery.
 Previous studies warn of the potential consequences of ignoring biotic
 interactions amongst recovering species, but we go further by quantifying
 how these interactions contributed to failed recoveries via impacts on the
 nesting demography of jointly recovering species. Multi-species management
 is paramount to realizing the ecosystem benefits of top predator recovery.
description: Observed nest occupancy,
 success and number of fledged young for osprey during
 1973-2012Nest occupancy, success
 and number of fledged young for osprey in Voyageurs National Park observed
 during 1973-2012 from aerial surveys. Predictors associated with each nest
 include descriptors for weather, ice-out dates, nest and foraging habitat,
 fish resources and various measures of potential intraguild predation and
 competition from bald eagles.OspreyData_JAE.xlsxHeronry occupancy and number of nests of great blue herons observed during 1973-2012Heronry occupancy and number of nests of great blue herons in Voyageurs National Park observed during 1973-2012 from aerial surveys. Predictors associated with each heronry include descriptors for nesting and foraging habitat, fish resources and various measures of potential intraguild predation and competition from bald eagles and osprey.HeronData_JAE.xlsx