Great Blue Heron (Ardea herodias)

Vennesland, Ross G.; Butler, Robert W.

doi:10.2173/bna.grbher3.02

Cited by 13 publications

(16 citation statements)

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“…Like most wading birds, the Little Blue Heron is constrained by its total leg length (22.52 AE 0.95 cm [mean AE SD]; N = 8; measurements provided from specimens at the Louisiana State University Museum of Natural Science) to feed in a narrow range of water depths (Rodgers and Smith 2012). The Great White Heron feeds on a variety of prey from small birds to frogs and fish, but it mostly feeds in shallow water when it is available (Vennesland and Butler 2011). It feeds in a range of water depths with a total average leg-length of 39 AE 2.1 cm (based on study skins at the University of Miami [Powell 1987]).…”

Section: Study Speciesmentioning

confidence: 99%

Time‐integrated habitat availability is a resource attribute that informs patterns of use in intertidal areas

Calle

Green

Strong

et al. 2018

Ecological Monographs

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In dynamic environments, resource availability may change by several orders of magnitude, over hours to months, but the duration of resource availability is not often included as a characteristic attribute of resources even though temporal resource dynamics might limit patterns of use. In our study of wading birds foraging in intertidal areas, tides cause large changes in the areal extent of shallow‐water foraging habitat (i.e., the resource), but tides also constrain the duration of availability, which is often overlooked. We hypothesized that temporal constraints on habitat availability from tides would be reflected in patterns of habitat use by foraging birds. We estimated the time‐integrated habitat availability and compared it to traditional habitat attributes (seagrass cover, substrate type, instantaneous water depth, and proximity to mangrove islands or deep water) that have strong evidential support for influencing patterns of use. To evaluate our hypotheses, we quantified habitat attributes at intertidal areas in the Florida Keys, USA, where wading birds were observed foraging (Little Blue Heron, Egretta caerulea: N = 183; Great White Heron, Ardea herodias occidentalis: N = 162). We tested for nonrandom use by sampling habitat attributes at two spatial scales around the observed feeding locations and we analyzed the data using a conditional logistic regression model. There was no evidence that seagrass cover or substrate explained patterns of use. The proximity of foraging locations relative to mangroves and to deep water were important at both spatial scales but had lower effect sizes (odds ratios) than time‐integrated habitat availability and water depth, and the latter may only serve as a physical constraint on access. We found support that time‐integrated habitat availability was a distinct resource attribute, had the greatest effect size (four‐ to eightfold change in relative probability of use), and best explained patterns of habitat use at the largest spatial scale. In studies of resource use where changes in resource availability are nonlinear or when strong constraints on access are imposed by behavior, incorporating time‐integrated estimates of resource availability into analyses can improve insights into spatiotemporal patterns of resource use.

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Section: Study Speciesmentioning

confidence: 99%

Time‐integrated habitat availability is a resource attribute that informs patterns of use in intertidal areas

Calle

Green

Strong

et al. 2018

Ecological Monographs

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“…The early success of osprey and herons, however, was short-lived at Voyageurs, and both species declined again in the early 1990s ( Figure 1). Eagles, ospreys and herons share similar life-history strategies, generally nesting in close proximity to large water bodies and often relying on fish as their main diets (Bierregaard, Poole, Martell, Pyle, & Patten, 2016;Buehler, 2000;Vennesland & Butler, 2011). However, ospreys and herons are more sensitive to inclement weather, frozen lakes and low fish abundance.…”

Section: Introductionmentioning

confidence: 99%

“…However, ospreys and herons are more sensitive to inclement weather, frozen lakes and low fish abundance. Adverse weather such as late ice-out dates, cold temperatures and high rainfall can reduce osprey and heron reproduction (Bierregaard et al, 2016;Vennesland & Butler, 2011). Ospreys and herons are also sensitive to changes in nesting habitat (Poole, 1989;Vennesland & Butler, 2011).…”

Section: Introductionmentioning

confidence: 99%

“…Adverse weather such as late ice-out dates, cold temperatures and high rainfall can reduce osprey and heron reproduction (Bierregaard et al, 2016;Vennesland & Butler, 2011). Ospreys and herons are also sensitive to changes in nesting habitat (Poole, 1989;Vennesland & Butler, 2011). Eagles, herons and ospreys nest in close proximity to ponds, lakes and rivers, but in Voyageurs, ospreys and herons nest predominantly on dead, standing trees within beaver ponds (Windels, 2017).…”

Section: Introductionmentioning

confidence: 99%

“…Eagles are dominant competitors and intraguild predators of ospreys and herons and, as such, may have important top-down effects on their behaviour and population recovery. Eagles are almost twice the size of ospreys and herons (Buehler, 2000), prey on eggs, chicks and adults of both species (Bierregaard et al, 2016;Vennesland & Butler, 2011) and steal food from ospreys (i.e., kleptoparasitism, Prevost, 1977). In Voyageurs, eagles arrive about a month before ospreys and herons, and may also compete directly for optimal nest sites (Ogden, 1975).…”

Section: Introductionmentioning

confidence: 99%

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Top‐down effects of repatriating bald eagles hinder jointly recovering competitors

Cruz

Windels

Thogmartin

et al. 2019

Journal of Animal Ecology

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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. 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. 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. 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. 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.

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Defining alternative futures and projecting their effects on the spatial distribution of wildlife habitats

Wilhere

Linders

Cosentino

2007

Landscape and Urban Planning

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Great Blue Heron (Ardea herodias)

Cited by 13 publications

References 0 publications

Time‐integrated habitat availability is a resource attribute that informs patterns of use in intertidal areas

Time‐integrated habitat availability is a resource attribute that informs patterns of use in intertidal areas

Top‐down effects of repatriating bald eagles hinder jointly recovering competitors

Defining alternative futures and projecting their effects on the spatial distribution of wildlife habitats

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