Shallow water availability coupled with anthropogenic degradation of seagrass beds limits wading bird food resources in dynamic coastal ecosystems. Identifying prey species critical to wading bird reproductive success and the environmental drivers of key prey species abundance is important for understanding how environmental stressors influence prey and change the quality of foraging patches. Little Blue Herons (Egretta caerulea) are reportedly generalists eating insects, crustaceans, and fish; however, the proportions of prey items in the diet may shift spatially and temporally from freshwater to marine systems during breeding and non-breeding periods. I investigated prey selection by Little Blue Herons in Florida at the Great White Heron National Wildlife Refuge and the western Florida Bay, during 2016 and 2017 breeding seasons by investigating prey availability at low-tide locations along mudflats compared to stomach regurgitate samples collected from Little Blue Heron chicks 1 to 4 weeks old. Little Blue Herons selected Gulf toadfish (Opsanus beta) and prawns (Farfantepenaeus spp.) from the estuarine environment, but also consumed terrestrial prey (e.g. tree crabs) suggesting Little Blue Heron foraging habitat is not restricted to tidal flats. Additionally, these results support the characterization of Little Blue Herons as a generalist. After identifying important prey species, I modeled the associations of selected prey species with submerged aquatic vegetation density and abiotic variables to better understand habitat preferences and important habitat characteristics that drive prey density. Models support total seagrass density and algal density as having the greatest effect on prey selected by Little Blue Herons. Prawn density has a strong positive association with seagrass density. Gulf toadfish (Opsanus beta) and prawns (Farfantepenaeus spp.) had strong positive association with algae while pipefish (Syngnathidae) had a strong negative association with algae suggesting algae density in seagrass meadows should be considered when assessing the quality of seagrass meadows for Little Blue Heron prey and habitat suitability. My results varied from previous studies where prawns and gulf toadfish were associated with specific seagrass species. Therefore, some Little Blue Heron prey species in south Florida may not be affected by changes in submerged aquatic vegetation community composition if submerged aquatic vegetation densities remain constant. Studies are needed that clarify the complex interactions between prey and specific habitat metrics to validate the strength of landscape scale drivers of wading bird prey densities in dynamic coastal ecosystems and to determine how these communities will respond to anthropogenic environmental change. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection

Made available in DSpace on 2014-08-20T14:31:29Z (GMT). No. of bitstreams: 1 dissertacao_fabiana_fedatto_bernardon.pdf: 2564105 bytes, checksum: 3adada5c7a15fdd6272eae15d9df82e8 (MD5) Previous issue date: 2013-02-27 / The Ardeidae family is composed of more than 60 species, being one of the largest and most representative families of birds with characteristics adapted to wetlands. Rio Grande do Sul is characterized by presenting ecosystems which harbor a unique diversity of waders, where there is the record of 13 species of Ardeidae. Due to lack of information on the diversity of helminths in the Ardeidae family in Rio Grande do Sul, the work was developed with the goal of identifying the helminthfauna of nine species of Ardeidae and determine the parameters of prevalence, mean abundance and mean intensity. Were examined 30 birds of the Ardeidae family (Pelecaniformes), Ardea alba , Ardea cocoi, Butorides striata, Bubulcus ibis, Egretta thula, Ixobrychus involucris, Nycticorax nycticorax , Syrigma sibilatrix e Tigrisoma lineatum from the natural environment of the cities of Pelotas, Capão do Leão e Rio Grande, RS, Brazil. The birds were necropsied to collect helminths, prepared in accordance with the protocols used for each group and identified. As a result there was obtained species of Trematoda, Nematoda and Acanthocephala and their parasitological parameters as follow below: Trematoda: Digenea, Amphimerus interruptus (P=3,3%; AM=0,1; IM= 3,0), Apharyngostrigea ardearum (P=40%; AM=18,6; IM= 46,6), Ascocotyle sp. (P=33,3%; AM=88,4; IM= 265,3), Clinostomum complanatum (P=30%; AM=1,1; IM= 3,8), Episthmium proximum (P=23,3%; AM=1,0; IM=4,2), Ithyclinostomum dimorphum (P=6,6%; AM=0,1; IM=2,5), Nephrostomum limai (P=10%; AM= 0,3; IM=3,6), Ribeiroia insignis (P=10%; AM=2,8; IM=28,0 ) and Stomylotrema sp. (P=3,3%; AM=0,03; IM=1,0) belonging to eight families: Nematoda: Contracaecum microcephalum (P=80%; AM=15,1; IM=18,8), Desportesius invaginatus (P=43,3%; AM=2,76; IM=6,3), Desmidocercella ardeae (P=16,6%; AM=1,3; IM=8,0), Eustrongylides sp. (P=13,3%; AM=1,3; IM=10,2) and Baruscapillaria sp. (P=10%; AM=0,5; IM=5,0). Acanthocephala: Acanthocephalus sp. (Echinorhynchidae) (P=3,33%; AM=0,03; IM=1,0), Andracantha sp. (P=33,3%; AM=15,2; IM=45,8), Arhythmorhynchus sp. (P=6,66%; AM=0,16; IM=2,5) and Polymorphus sp. (Plagiorhynchidae) (P=13,3%; AM=1,3; IM=10,2). Tigrisoma lineatum was the only negative for all groups Ixobrychus involucris was negative for the presence of Trematoda and Bubulcus ibis negative for acanthocephalans. The Trematoda, Nematoda and Acanthocephala mentioned above are for the first time recorded in the Ardeidae family in Rio Grande do Sul in Brazil, some of the hosts and their helminth characterizes first occurrence. We have found insulated proglottids of cestodes in small and large intestine in some birds, but could not identify them. / A família Ardeidae é composta por mais de 60 espécies sendo uma das maiores e mais representativas famílias de aves com características adaptadas às áreas úmidas. O Rio Grande do Sul caracteriza-se por apresentar ecossistemas que abrigam uma diversidade ímpar de aves pernaltas onde há o registro de 13 espécies de ardeídeos. Devido a escassez de informações sobre a diversidade de helmintos em Ardeidae no Rio Grande do Sul, desenvolveu-se o trabalho com o objetivo de identificar a helmintofauna de nove espécies de ardeídeos e determinar a os parâmetros de prevalência, abundância e intensidade médias. Foram examinados 30 aves. Ardea alba, Ardea cocoi, Butorides striata, Bubulcus ibis, Egretta thula, Ixobrychus involucris, Nycticorax nycticorax, Syrigma sibilatrix e Tigrisoma lineatum, provenientes de ambiente natural dos municípios de Pelotas, Capão do Leão e Rio Grande RS, Brasil. As aves foram necropsiadas para a coleta dos helmintos, preparadas de acordo com os protocolos utilizados para cada grupo e identificadas. Como resultado obteve-se espécies de trematódeos, nematóides e acantocéfalos e seus parâmetros parasitológicos como seguem a seguir: Trematoda: Digenea, Amphimerus interruptus (P=3,3%; AM=0,1 ;IM=3,0), Apharyngostrigea ardearum (P=40%; AM=18,6; IM= 46,6), Ascocotyle sp. (P=33,3%; AM=88,4; IM= 265,3), Clinostomum complanatum (P=30%; AM=1,1; IM=3,8), Episthmium proximum (P=23,3%; AM=1,0; IM=4,2), Ithyclinostomum dimorphum (P=6,6%; AM=0,1; IM=2,5), Nephrostomum limai (P=10%; AM= 0,3; IM=3,6), Ribeiroia insignis (P=10%; AM=2,8; IM=28,0) e Stomylotrema sp. (P=3,3%; AM=0,03; IM=1,0) pertencentes a oito famílias; Nematoda: Contracaecum microcephalum (P=80%; AM=15,1;IM=18,8),Desportesius invaginatus(P=43,3%; AM=2,76; IM=6,3), Desmidocercella ardeae (P=16,6%; AM=1,3; IM=8,0), Eustrongylides sp. (P=13,3%; AM=1,3; IM=10,2) e Baruscapillaria sp. (P=10%; AM=0,5; IM=5,0). Acanthocephala: Acanthocephalus sp. (Echinorhynchidae) (P=3,33%; AM=0,03; IM=1,0), Andracantha sp. (P=33,3%; AM=15,2; IM=45,8), Arhythmorhynchus sp. (P=6,66%; AM=0,16; IM=2,5) e Polymorphus sp. (Plagiorhynchidae) (P=13,3%; AM=1,3; IM=10,2). Tigrisoma lineatum foi o único ardeídeo negativo para todos os grupos, enquanto que Ixobrychus involucris quanto à presença de trematódeos e Bubulcus ibis quanto à presença de acantocéfalos. Os trematódeos, nematóides e acantocéfalos citados anteriormente são pela primeira vez registrados em ardeídos no Rio Grande do Sul. No Brasil, alguns dos hospedeiros e respectivos helmintos constituem primeira ocorrência. Foram encontradas proglotes isoladas de cestóides no intestino delgado e grosso em algumas aves, porém não foi possível identificá-las.

Nests of the Black-crowned Night Heron and the Snowy Egret were examined in five central Utah colonies in 1973 to determine the spatial distribution within the colony. Nest locations of the 1085 nests of the two species were plotted to the nearest foot with an alidade and plane table. Tests of randomness, clump size, association, segregation, and T distribution were utilized. No differences between species were noted for the distance to the nearest and the next nearest nest. The Night Heron nested closer to other Night Herons and more often than did the Snowy Egret which non-significantly selected either species to nest closest. The Snowy Egret nests were 1.7 times higher than the Night Heron nests. Both species nests were aggregated within the colony. The association between the species within the habitat was positive but were segregated within the colony. Nest succession within a colony indicates that the Snowy Egret becomes more selective as time progresses but that the Night Heron remains selective throughout the entire season.

This study was conducted to augment the limited information available regarding the Snowy Egret in the Utah Lake area of Utah. Field observations included the following: nesting habits; egg and clutch sizes; sexual, defense, and feeding behaviors. Analysis was made of the distinguishing subspecies characteristics (culmen, tarsus, and wing length) of the Snowy Egrets and of the distribution of the birds. Field observations showed that growth measurements of the young varied from 16.75 g at hatching to 260.58 g after 17 days. Culmen and tarsus measurements were 15.41 mm and 14.12 mm to 53.18 mm and 62.18 mm, respectively, after 17 days. The average clutch size was 2.93 eggs per clutch. The average egg measured 43.85 mm by 32.44 mm. Hatching success was 50.85% in the two major periods of hatching noted. The lack of distinct lines of differentiation between existing subspecies leads the author to question the validity of the current subspecies designations.