Space Use and Movements of Adult Reddish Egrets (<i>Egretta rufescens</i>) During Winter

Koczur, Lianne M.; Kent, Gina M.; Ballard, Bart M.; Meyer, Kenneth D.; Green, M. Clay

doi:10.1675/063.041.0102

Cited by 11 publications

(17 citation statements)

References 29 publications

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“…For example, most of the samples from Louisiana were collected from a small colony on an island, which did not have documented nesting Reddish Egrets until recently (Selman & Davis, 2015). Therefore, the unique genetic deme in Louisiana, which also included some individuals from Florida (Figure 1d) (Geary et al, 2015;Koczur et al, 2018;Lamb et al, 2017), we found little evidence to support that immigrants breed at high frequencies with TA B L E 3 Analysis of Molecular Variation (AMOVA) tests for four different management unit (MU) models ( Figure 1a) Regarding dispersal, Geary et al (2015) found only one female out of four dispersed greater than 120 km from their natal colony, whereas 13 out of 21 males dispersed greater than 120 km.…”

Section: Discussionmentioning

confidence: 99%

“…This hypothesis is supported by well-defined demes for Baja California, Chiapas, and the Bahamas (Figure 1d Florida has two haplotypes in total. One of them is Haplotype 3, which is expected given the short-distance movements by female's between Florida and the Bahamas inferred from banding and telemetry data (Geary et al, 2015;Koczur et al, 2018;Lamb et al, 2017).…”

Section: Discussionmentioning

confidence: 99%

“…The second objective was to confirm the presence of sex-biased dispersal, which was previously detected through banding and telemetry data (Geary et al, 2015;Koczur et al, 2018). This is important to conservation because differences between the philopatric sex and dispersing sex may require different management strategies (Tucker et al, 2017).…”

Section: Introductionmentioning

confidence: 95%

“…Color banding studies have revealed movements between the Western and Central MUs (e.g., Baja California birds to Chiapas, Mexico) and between the Central and Eastern populations (e.g., Yucatan, Mexico birds to Florida, U.S.A.) (Green & Palacios unpublished data). Dispersing juveniles are predominantly male whereas adult males and females exhibit annual migratory behavior (Geary et al., 2015; Koczur et al., 2018). These data suggest differences in movement behavior between males and females despite relatively small sample sizes.…”

Section: Introductionmentioning

confidence: 99%

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A re‐evaluation of management units based on gene flow of a rare waterbird in the Americas

et al. 2020

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The maintenance of gene flow in species that have experienced population contractions and are geographically fragmented is important to the maintenance of genetic variation and evolutionary potential; thus, gene flow is also important to conservation and management of these species. For example, the Reddish Egret (Egretta rufescens) has recovered after severe population reductions during the 19th and 20th centuries, but population numbers remain below historical levels. In this study, we characterized gene flow among management units of the Reddish Egret by using ten nuclear microsatellite markers and part of the mitochondrial (mtDNA) control region from 176 nestlings captured at eight localities in Mexico (Baja California, Chiapas, Tamaulipas, and Yucatan), the USA (Texas, Louisiana, and Florida), and the Bahamas. We found evidence of population structure and that males disperse more often and across longer distances compared with females, which is congruent with previous banding and telemetry data. The maternally inherited mtDNA and biparentally inherited microsatellite data supported slightly different MU models; however, when interpreted together, a four MU model that considered population structure and geographic proximity was most optimal. Namely, MU 1 (Baja California); MU 2 (Chiapas); MU 3 (Yucatan, Tamaulipas, Texas, and Louisiana); and MU 4 (Florida and the Bahamas). Regions outside our sampled localities (e.g., the Greater Antilles and South America) require additional sampling to fully understand gene flow and movement of individuals across the species' entire range. However, the four MUs we have defined group nesting localities into genetically similar subpopulations, which can guide future management plans.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

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A re‐evaluation of management units based on gene flow of a rare waterbird in the Americas

et al. 2020

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“…Advanced tracking methods (e.g., ARGOS or GPS tracking) gather real-time data with accurate location information that traditional bird surveys cannot provide. The resolution of these data can account for variation in movement and habitat use ( Koczur et al, 2018 ; Takano & Haig, 2004 ), thereby enhancing our ability to evaluate the habitat quality for birds and yield data to guide habitat management and conservation (e.g., El-Hacen et al, 2013 ; Mitchell et al, 2016 ).…”

Section: Introductionmentioning

confidence: 99%

Spatial ecology of little egret (Egretta garzetta) in Hong Kong uncovers preference for commercial fishponds

Pang

Sung²,

Chung³

et al. 2020

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Many natural wetlands have been converted to human-influenced wetlands. In some instances, human-influenced wetlands could provide complementary habitats for waterbirds, compensating for the loss of natural wetlands. Inner Deep Bay in Hong Kong is composed of both natural and human-influenced wetlands and is under immense development pressure. From an ecology perspective, we need to understand if different wetland types play the same ecological role. To achieve this, we tracked nine little egrets (Egretta garzetta) using GPS loggers for 14 months to study their spatial ecology, home range, movement and habitat use. We found that over 88% of the home range of all individuals comprised of wetlands (commercial fishponds, mangrove, gei wai, channel, and intertidal mudflat). Among these wetland types, nearly all (seven of nine) individuals preferred commercial fishponds over other habitats in all seasons. Little egrets exhibited seasonal movement and habitat use among seasons, with largest home range, greatest movement, and most frequent visits to commercial fishponds in winter compared to spring and autumn. Our results highlight the significant role of commercial fishponds, providing a feeding ground for little egrets. However, other wetland types cannot be ignored, as they were also used considerably. These findings underscore the importance of maintaining a diversity of wetland types as alternative foraging and breeding habitats.

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Space use and site fidelity of wintering whooping cranes on the Texas Gulf Coast

et al. 2022

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The Aransas‐Wood Buffalo population (the only non‐reintroduced, migratory population) of endangered whooping cranes (Grus americana) overwinters along the Texas Gulf Coast, USA. Understanding whooping crane space use on the wintering grounds reveals essential aspects of this species' ecology, which subsequently assists with conservation. Using global positioning system telemetry data from marked whooping cranes during 2009–2017, we fit continuous‐time stochastic process models to describe movement and home range using autocorrelated kernel density estimation (AKDE) and explored variation in home range size in relation to age, sex, reproductive status, and drought conditions. We used the Bhattacharyya coefficient of overlap and distance between home range centroids to quantify site fidelity. We examined the effects of time between winter home ranges and the sex of the crane on site fidelity using Bayesian mixed‐effects beta regression. Winter whooping crane 95% AKDE home range size averaged 30.1 ± 45.2 (SD) km2 (median = 14.3, range = 1.1–308.6). Home ranges of sub‐adult females were approximately 2 times larger than those of sub‐adult males or families. As drought worsened, home ranges typically expanded. Between consecutive years, the home ranges of an adult crane exhibited 68 ± 31% overlap (site fidelity), but fidelity to winter sites declined in subsequent winters. The overlap of adult home ranges with the nearest unrelated family averaged 33 ± 28%. As a whooping crane aged, overlap with its winter home range as a juvenile declined, regardless of sex. By 4 years of age, a whooping crane had approximately 14 ± 28% overlap with its juvenile winter home range. Limited evidence suggested male whooping cranes return to within 2 km of their juvenile home range by their fifth winter. Previous data obtained from aerial surveys led ecologists to assume that whooping crane families normally used small areas (~2 km2) and expressed persistent site fidelity. Our analyses showed <8% of families had home ranges ≤2 km2, with the average area 15 times greater, and waning site fidelity over time. Our work represents an analysis of whooping crane home ranges for this population, identifying past misconceptions of winter space use and resulting in better estimates of space requirements for future conservation efforts.

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Space Use and Movements of Adult Reddish Egrets (Egretta rufescens) During Winter

Abstract: BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.

Cited by 11 publications

References 29 publications

A re‐evaluation of management units based on gene flow of a rare waterbird in the Americas

A re‐evaluation of management units based on gene flow of a rare waterbird in the Americas

Spatial ecology of little egret (Egretta garzetta) in Hong Kong uncovers preference for commercial fishponds

Space use and site fidelity of wintering whooping cranes on the Texas Gulf Coast

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