No description available.

The linking of breeding and nonbreeding grounds of migratory birds is of great conservation and theoretical importance. In theory, connecting these geographically disparate areas allows for a more complete understanding of annual events, and a first step into identifying where in the annual cycle limitations to fitness may be occurring. <p>The Loggerhead Shrike (<i>Lanius ludovicianus</i>) is a Species at Risk in Canada, and its decline is attributed to habitat loss on both the breeding and wintering grounds. In the fall, Loggerhead Shrikes from breeding areas of prairie Canada (<i>L. l. excubitorides</i>), the focus of this study, move south along the Gulf States of the United States and Mexico to wintering areas that are already occupied year-round by resident shrikes. However, the habitat structure and variability for both migrants and resident Loggerhead Shrikes have not been studied well on the wintering grounds. Thus, it has been difficult to adequately evaluate the relative contribution of changes in wintering areas to the decline of Loggerhead Shrike populations. To identify the wintering grounds of Loggerhead Shrikes that breed in prairie Canada, I used stable hydrogen isotope (δD) analysis of feathers and claws and microsatellite DNA from feathers. In North America, δD measurements from feathers provide information on latitude of origin, while DNA can be related to an affiliation to a breeding population. Since several authors suggested that Loggerhead Shrike completed their preformative and formative molt on the breeding grounds prior to fall migrations, I reasoned that δD analysis of tertial feathers sampled on the wintering grounds would correspond to δD in precipitation from the breeding grounds. Similarly, I used DNA microsatellite markers and Bayesian clustering analysis to detect patterns of population genetic structure within the range of Western Loggerhead Shrikes (<i>L. l. excubitorides</i>) in Canada and consequently use these to infer breeding origin of shrikes sampled in Mexico. I based the categorization of resident and migrant Loggerhead Shrikes sampled in Mexico on δD analysis of feathers. Based on evaluation of observed and expected δD values of feathers, I determined that migrant shrikes used northeastern (63.8%) and south-central (73.7%) Mexico to winter. Microsatellite DNA and assignment tests, suggested that wintering migrant shrikes occupied north-central (18.6%) and northeastern (20.3%) Mexico. Differential habitat occupancy analyses, suggested that, in northeastern Mexico, wintering sites occupied by Loggerhead Shrike sites were structurally different from random unoccupied sites (MRPP, T = -8.04, P < 0.001, n = 354). An important difference was that, on average, occupied habitat contained shorter tall shrubs and huisache and fewer tall shrubs, mesquite and huisache. Similarly, residents shrikes occupied structurally different habitats (MRPP, T = -2.95, P = 0.01, n = 146) that had less percent cover of bare ground than those sites occupied by migrants. Based on these habitat results, I surmise that habitat availability may be a limiting factor for both resident and migratory shrike populations in northeastern Mexico.

The linking of breeding and nonbreeding grounds of migratory birds is of great conservation and theoretical importance. In theory, connecting these geographically disparate areas allows for a more complete understanding of annual events, and a first step into identifying where in the annual cycle limitations to fitness may be occurring. <p>The Loggerhead Shrike (<i>Lanius ludovicianus</i>) is a Species at Risk in Canada, and its decline is attributed to habitat loss on both the breeding and wintering grounds. In the fall, Loggerhead Shrikes from breeding areas of prairie Canada (<i>L. l. excubitorides</i>), the focus of this study, move south along the Gulf States of the United States and Mexico to wintering areas that are already occupied year-round by resident shrikes. However, the habitat structure and variability for both migrants and resident Loggerhead Shrikes have not been studied well on the wintering grounds. Thus, it has been difficult to adequately evaluate the relative contribution of changes in wintering areas to the decline of Loggerhead Shrike populations. To identify the wintering grounds of Loggerhead Shrikes that breed in prairie Canada, I used stable hydrogen isotope (δD) analysis of feathers and claws and microsatellite DNA from feathers. In North America, δD measurements from feathers provide information on latitude of origin, while DNA can be related to an affiliation to a breeding population. Since several authors suggested that Loggerhead Shrike completed their preformative and formative molt on the breeding grounds prior to fall migrations, I reasoned that δD analysis of tertial feathers sampled on the wintering grounds would correspond to δD in precipitation from the breeding grounds. Similarly, I used DNA microsatellite markers and Bayesian clustering analysis to detect patterns of population genetic structure within the range of Western Loggerhead Shrikes (<i>L. l. excubitorides</i>) in Canada and consequently use these to infer breeding origin of shrikes sampled in Mexico. I based the categorization of resident and migrant Loggerhead Shrikes sampled in Mexico on δD analysis of feathers. Based on evaluation of observed and expected δD values of feathers, I determined that migrant shrikes used northeastern (63.8%) and south-central (73.7%) Mexico to winter. Microsatellite DNA and assignment tests, suggested that wintering migrant shrikes occupied north-central (18.6%) and northeastern (20.3%) Mexico. Differential habitat occupancy analyses, suggested that, in northeastern Mexico, wintering sites occupied by Loggerhead Shrike sites were structurally different from random unoccupied sites (MRPP, T = -8.04, P < 0.001, n = 354). An important difference was that, on average, occupied habitat contained shorter tall shrubs and huisache and fewer tall shrubs, mesquite and huisache. Similarly, residents shrikes occupied structurally different habitats (MRPP, T = -2.95, P = 0.01, n = 146) that had less percent cover of bare ground than those sites occupied by migrants. Based on these habitat results, I surmise that habitat availability may be a limiting factor for both resident and migratory shrike populations in northeastern Mexico.

1. This thesis presents the results of a population ecology study of the Dipper Cinclus cinclus in the western Ochil Hills, Tayside and Central Regions, Scotland between April 1985 and May 1988. 2. Particular attention was given to factors affecting juvenile survival between fledging and recruitment to the breeding population. These included investigation of the variation and significance of body size, plumage colour. dispersal distance, home range acquisition, dominance status and autumn body condition. 3. Overwinter survival was higher in adults than juveniles. Juvenile females had a greater overwinter survival and recruitment rate than juvenile males. Few body size measures were consistently associated with overwinter survival,though juvenile females with longer wings and tarsi tended to survive better. 4. Males had higher plumage brightness scores than females and, within sexes, adults were brighter than juveniles. Overall, survival overwinter and recruitment were not related to plumage brightness. 5. A laboratory test arena was developed for assessing dominance relations in small groups of temporarily captive birds. Social status between age and sex classes was correlated with plumage brightness. Within age classes, plumage brightness was a significant predictor of status in adults, but body size was more important in juveniles. 6. Females settled farther from their natal sites than males; most of this dispersal was completed soon after independence. The relationship between dispersal and dominance is discussed and a model developed. 7. Autumn population density was manipulated locally in a series of experimental juvenile introductions. Numbers rapidly returned to initial levels, though earlier released individuals persisted for longer. About 20% of introduced birds recruited, mainly higher status males. 8. Body composition of a small sample of birds collected between September and April is described. Lipid stores were greatest in winter and least in spring. A method for measuring pectoralis muscle thickness was developed using an ultrasound-based technique. 9. Condition indices derived from "ultrasound" measurements on live birds were used to evaluate the importance of protein reserves in overwinter survival. Males in good condition in autumn were more likely to recruit but no trend was apparent in females. 10. Two periods of high juvenile losses were identified: post-independence and late autumn. Predation could only be implicated in the former. The agent of late autumn losses was not proven but probably involved territorial intolerance and the consequent exclusion of subordinates to fringe habitats. It is concluded that density-dependent changes in mortality, related to dominance and mediated via dispersal, caused Dipper numbers tobe matched to available resources, principally food and breeding territories.

<p>Hemosporidije&nbsp; kao&nbsp; krvno&nbsp; prenosivi&nbsp; paraziti, veoma su rasprostranjeni u populacijama ptica &scaron;irom&nbsp; planete.&nbsp; Izazivaju&nbsp; avijarnu&nbsp; malariju&nbsp; ili stanje&nbsp; slično&nbsp; njoj,&nbsp; a&nbsp; prenose&nbsp; se&nbsp; preko insekatskih&nbsp; vektora.&nbsp; Hemosporidije&nbsp; su&nbsp; veoma dobro&nbsp; proučene&nbsp; u&nbsp; severnoj&nbsp; i&nbsp; zapanoj&nbsp; Evropi&nbsp; i Severnoj&nbsp; Americi.&nbsp; S&nbsp; obzirom&nbsp; da&nbsp; su hemosporidije&nbsp; slabije&nbsp; izučavane&nbsp; u Palearktičkom&nbsp; migratornom&nbsp; sistemu&nbsp; zapadnog Balkana, osnovni cilj bio je da se istraži koje su vrste&nbsp; tri&nbsp; ispitivana&nbsp; roda&nbsp; hemosporidija <em>Plasmodium</em>,&nbsp; <em>Haemoproteus&nbsp;</em> i<em>&nbsp; Leucocytozoon</em> zastupljene&nbsp; kod&nbsp; različitih&nbsp; migratornih&nbsp; grupa ptica&nbsp; pevačica&nbsp; u&nbsp; Srbiji.&nbsp; Rasprostranjenje,prevalenca&nbsp; i&nbsp; parazitemija&nbsp; ustanovljene&nbsp; su&nbsp; na dva načina: pregledanjem krvnih razmaza ptica i&nbsp; pomoću&nbsp; molekularne&nbsp; (PCR)&nbsp; metode. Sakupljeno&nbsp; je&nbsp; 202&nbsp; uzorka&nbsp; krvi&nbsp; sa&nbsp; sedam lokaliteta.&nbsp; Zaraza&nbsp; rodovima <em>Plasmodium,Haemoproteus</em>&nbsp; i&nbsp; <em>Leucocytozoon</em>&nbsp; ustanovljena je kod&nbsp; 66&nbsp; jedinki,&nbsp; sa&nbsp; ukupnom&nbsp; prevalencom&nbsp; od 32,7%.&nbsp; Najče&scaron;ći&nbsp; rod&nbsp; hemosporidija&nbsp; bilo&nbsp; je <em>Haemoproteus</em>&nbsp; sa&nbsp; prevalencom&nbsp; od&nbsp; 26,1%.&nbsp; Sve zaražene&nbsp; ptice&nbsp; bile&nbsp; su&nbsp; adultne.&nbsp; Samo&nbsp; je&nbsp; jedna ptica&nbsp; imala&nbsp; ko-infekciju.&nbsp; Ustanovljena&nbsp; je&nbsp; 31 loza,&nbsp; od&nbsp; čega&nbsp; su&nbsp; dve&nbsp; potpuno&nbsp; nove&nbsp; i neotkrivene&nbsp; do&nbsp; sada.&nbsp; Loza&nbsp; CCF25&nbsp; iz&nbsp; roda <em>Plasmodium,</em>&nbsp; izolovana&nbsp; je&nbsp; kod&nbsp; obične&nbsp; zebe (<em>Fringilla&nbsp; coelebs)</em>,&nbsp; a&nbsp; dok&nbsp; ORIORI04&nbsp; pripada rodu&nbsp; <em>Leucocytozoon</em>&nbsp; i&nbsp; izolovana&nbsp; je&nbsp; kod vuge(<em>Oriolus&nbsp; oriolus</em>).&nbsp; Loza&nbsp; GRW06<br />(<em>Plasmodium&nbsp; elongatum)&nbsp;</em> izolovana&nbsp; je&nbsp; po&nbsp; prvi put&nbsp; kod&nbsp; obične&nbsp; zebe,&nbsp; dok&nbsp; su&nbsp; loze&nbsp; PARUS20&nbsp; i PARUS25&nbsp; (<em>Leucocytozoon&nbsp; sp</em>.)&nbsp; po&nbsp; prvi&nbsp; put zabeležene&nbsp; kod&nbsp; planinske&nbsp; sive&nbsp; (<em>Poecile montanus)</em>&nbsp; i&nbsp; ćubaste&nbsp; senice&nbsp; (<em>Lophophanes cristatus)</em>.&nbsp; Većina&nbsp; ptica&nbsp; (29)&nbsp; imala&nbsp; je&nbsp; srednji nivo&nbsp; parazitemije.&nbsp; Ustanovljena&nbsp; je&nbsp; značajna razlika&nbsp; u&nbsp; prevalenci&nbsp; između&nbsp; stanarica&nbsp; i delimičnih&nbsp; selica.&nbsp; Razlika&nbsp; u&nbsp; srednjoj parazitemiji bila&nbsp; je&nbsp; značajna&nbsp; takođe&nbsp; između stanarica i delimičnih selica.</p> / <p>Avian&nbsp; haemosporidians&nbsp; are&nbsp; vector-transmitted blood&nbsp; parasites&nbsp; distributed&nbsp; worldwide,&nbsp; abundant in&nbsp; many&nbsp; bird&nbsp; families&nbsp; and&nbsp; well-studied&nbsp; across Europe and&nbsp; North&nbsp; America.&nbsp; Since&nbsp; avian&nbsp; hemosporidians&nbsp; were&nbsp; poorly&nbsp; examined&nbsp; in&nbsp; the Palearctic&nbsp; migratory&nbsp; flyways&nbsp; of&nbsp; the&nbsp; Western Balkans, the goal of this study was to&nbsp; investigate what&nbsp; species&nbsp; of&nbsp; three&nbsp; haemosporidian&nbsp; genera<em> Plasmodium,</em>&nbsp; <em>Haemoproteus</em>&nbsp; and&nbsp;<em> Leucocytozoon</em> infect&nbsp; both&nbsp; resident&nbsp; and&nbsp; migratory&nbsp; passerine birds in Serbia. The&nbsp; prevalence, distribution and parasitemia&nbsp; of&nbsp; avian&nbsp;&nbsp; haemosporidian&nbsp; infections were&nbsp; screened&nbsp; using&nbsp; both&nbsp; nested&nbsp; PCR&nbsp; method and microscopy observation. Out of 202 sampled birds&nbsp; at&nbsp; seven&nbsp; localities,&nbsp; 66&nbsp; were&nbsp; positive&nbsp; for haemosporidians.&nbsp; Total&nbsp; prevalence&nbsp; was&nbsp; 32.7%. Great majority of infected birds (29 individuals) had&nbsp; moderate&nbsp; level&nbsp; of&nbsp; parasitemia.&nbsp; The&nbsp; most abundant&nbsp; haemosporidian&nbsp; genus&nbsp; was Haemoproteus&nbsp; with&nbsp; prevalence&nbsp; of&nbsp; 26.1%.&nbsp;&nbsp;&nbsp; All infected&nbsp; birds&nbsp; were&nbsp; adults,&nbsp; whereas&nbsp; none&nbsp; of tested&nbsp; juveniles&nbsp; were&nbsp; infected.&nbsp; Mixed&nbsp; infection was recorded only in one bird. We identified 31 genetic&nbsp; lineages&nbsp; of&nbsp; haemosporidian&nbsp; parasites. Two new cytochrome&nbsp; b&nbsp; lineages of&nbsp; <em>Plasmodium</em> and&nbsp;<em> Leucocytozoon</em>&nbsp; were identified and found in hosts Common Chaffinch (<em>Fringilla coelebs</em>) and Golden&nbsp; Oriole&nbsp; (<em>Oriolus&nbsp; oriolus)</em>.&nbsp; We&nbsp; identified three&nbsp; new&nbsp; host&nbsp; records&nbsp; for&nbsp; previously&nbsp; known lineages.&nbsp; The&nbsp; lineage&nbsp; GRW06&nbsp; (<em>Plasmodium elongatum</em>)&nbsp; occurred&nbsp; in&nbsp; Common&nbsp; Chaffinch, while&nbsp; the&nbsp; lineages&nbsp; PARUS20&nbsp; and&nbsp; PARUS25 (<em>Leucocytozoon sp</em>.) were recorded in Willow Tit (<em>Poecile&nbsp;</em> <em>montanus</em>)&nbsp; and&nbsp; Crested&nbsp; Tit (<em>Lophophanes cristatus)</em>,&nbsp; respectively. We found statistically&nbsp; significant&nbsp; differences&nbsp; in&nbsp; the prevalence&nbsp; of&nbsp; three&nbsp; haemosporidian&nbsp; genera among resident and partial migratory birds.&nbsp; The difference&nbsp; in&nbsp; mean&nbsp; parasitemia&nbsp; was&nbsp; significant only between resident and partial migrants.</p>

1. Cost constraints in models of territory size are based on time/activity/laboratory estimates that predict birds using larger territories will incur higher energy costs. The predicted form of the cost constraint may be linear, accelerating or decelerating depending on assumptions inherent in the models. The aim of this study was to assess the reality and form of the cost constraint by making direct measurements of the energy costs of territory use in birds that occupy territories of different size and shape; polygonal territories represented by the robin Erithacus rubecula, and linear by the dipper Cinclus cinclus. Free-living energy expenditure was measured using the doubly-labelled water technique, whilst simultaneously recording patterns of territory use by radio-tracking. 2. Territorial robins concentrated their activity in one or more foraging patches located in bushes. Range polygons containing all the foraging patches used by an individual provided estimates of territory area, and were generally of high eccentricity. A small proportion of robins was classified as non-territorial based on range polygon areas. Furthermore, while territorial robins showed high fidelity to ranges over the short term (days), non-territorial individuals were nomadic. Over the longer term (months), however, some territorial robins showed range drift. Dippers similarly used preferred core regions within ranges, although there was no selection for particular habitat features. 3. Because robins occupied territory polygons which varied from polygonal to highly linear, work was focused on this species to allow intra-specific comparison. Robins tended to commute between foraging patches by flying. It was appropriate, therefore, to describe territories in terms of a number of patches linked by a network of flight paths. This generated two further measures of territory size; the number of patches used and the total flight distance between patches. 4. The robins exploited a renewing food supply. Predictions were tested concerning the temporal scheduling of visits to foraging patches within territories. Patches tended to be separated by flight paths of similar lengths, and were visited in a regular sequence. Although the number of foraging patches used varied, all territories had similar total core areas. Robins using many small foraging patches commuted between patches more often and covered a larger total flight distance during each foraging circuit of the territory. The configurations of foraging patches were used in a highly linear manner. This was true even if the territory containing them was of low eccentricity. 5. Changes in structure and pattern of use varied predictably with territory size, and could be described mathematically. Based on this and published time/activity budgets, a suite of models was developed to predict how energy costs would vary with number of patches used and total flight distance between patches. Models were tested by directly measuring the energy expenditure of robins using different territories. The number of patches used and total flight distance between patches were both significantly correlated with energy expenditure, while territory area was not. One of the models showed a significant fit to the observed data, and suggested that the form of the energy cost constraint on territory size was linear. The effect of territory shape on energy costs was minimal. The implications of these results for models of territory size are discussed. 6. The slope and elevation of the energy cost constraint varied with the morphology of territory occupants. Based on this, an association of morphology with territory size was predicted; robins of lower mass and wing-loading using larger territories. The observed data supported these predictions, and suggested a possible genetic predisposition to particular patterns of territory occupancy in the robin.

The roles of phylogeny and body size in avian heat stress physiology, and how they interact to set the upper limits to heat dissipation capacity, are largely unexplored. Determining thermal end points and maximum capacity for evaporative heat dissipation in species from diverse ecological guilds and evolutionary clades is vital for understanding species-specific vulnerability to future climatic scenarios. I measured evaporative water loss (EWL), resting metabolic rate (RMR) and body temperature (Tb) in three arid-zone passerines and three columbids of varying mass, namely the scaly-feathered weaver (Sporopipes squamifrons, ~11 g, SFW), sociable weaver (Philetairus socius, ~26 g, SW), white-browed sparrow weaver (Plocepasser mahali, ~40 g, WBW), Namaqua dove (Oena capensis, ~37 g, ND), laughing dove (Spilopelia senegalensis, ~89 g, LD) and Cape turtle dove (Streptopelia capicola, ~148 g, CTD) at maximum air temperatures (Ta) of 48–60°C. I found that evaporative water loss increased approximately linearly in all six species above a Ta of ~ 40 °C, which resulted in SFW, SW, WBW, ND, LD and CTD dissipating a maximum of 140, 220, 190, 498, 218 and 231 % of metabolic heat loads at the highest Tas respectively. All six species used facultative hyperthermia at high Tas and were able to regulate Tb up to and just beyond Tb = 45 °C. At the highest Tas experienced, passerines exhibited uncontrolled increases in Tb above 45 °C, resulting in 57, 100 and 100 % of SFW, SW and WBW respectively, reaching thermal limits at Ta = 48, 52 and 54 °C. Very few doves exhibited uncontrolled hyperthermia or reached thermal limits at their highest respective test Tas (Ta = 56, 68 and 60 °C in CTD, LD and ND respectively), suggesting that these birds could potentially survive higher Tas, and that lethal Tb was marginally higher than my conservative estimations. A conventional analysis found significant differences between doves and passerines in the slopes of EWL as well as the magnitude of the change in RMR, EWL and Tb between Ta = 35 and 48 °C. However, once phylogeny was controlled for, these differences were shown to be a result of phylogenetic inertia. Both a conventional analysis and a phylogenetic independent contrast (PIC) found a significant effect of body mass on slope of EWL, change in EWL (PIC only) and change in Tb between Ta = 35 and 48 °C. From the results of this study, I argue that by utilizing high ratios of cutaneous EWL to respiratory EWL, doves generate much less metabolic heat at high Tas than passerines. I suggest that larger passerines are better able to tolerate heat than smaller passerines, whereas the opposite is the case in doves. The lack of data from small doves obscured this finding in the conventional and PIC analyses. Further studies on the upper limits to the avian capacity for evaporative cooling and heat tolerance are critical for larger-scale mechanistic modeling of vulnerability to extreme heat events under current and future climate scenarios. / Dissertation (MSc)--University of Pretoria, 2014. / DST/NRF Centre of Excellence at the Percy FitzPatrick Institute (University of Cape Town) / University of New Mexico / Zoology and Entomology / MSc / Unrestricted

No description available.

Atualmente muitas espécies nativas de pássaros são consideradas raras no Brasil, pois são capturadas de forma indiscriminada por traficantes de animais e são então comercializadas, fazendo com que sejam encontradas cada vez mais em menor quantidade em seus habitats naturais. Animais confiscados do tráfico têm sido submetidos a programas de soltura ou relocação, atentando-se para que os mesmos não representem risco à população nativa. Passeriformes silvestres, saudáveis ou doentes, podem carrear uma grande diversidade de microorganismos e, portanto, o conhecimento sobre o status sanitário de animais apreendidos do tráfico que serão submetidos a programas de soltura, permite uma avaliação quanto à possibilidade destes animais atuarem como portadores de agentes patogênicos bem como atua como elemento esclarecedor da epidemiologia de doenças transmissíveis, aspecto fundamental para a preservação da saúde animal e também humana. O presente estudo procurou avaliar a ocorrência e frequência de bactérias aeróbias e anaeróbias facultativas bem como de fungos em suabes obtidos de cloacas de passeriformes silvestres apreendidos do tráfico e que serão submetidos a programas de soltura. Foram realizados testes de suscetibilidade in vitro dos isolados de E. coli frente a diferentes antimicrobianos utilizando-se o método de disco difusão, bem como a pesquisa de diversos genes codificadores de fatores de virulência nos mesmos através reação em cadeia da polimerase. A maior parte dos passeriformes (62,5%) avaliados apresentou uma microbiota cloacal constituída por bactérias aeróbias e/ou anaeróbias facultativas e/ou fungos, sendo que os microorganismos mais frequentemente isolados foram Staphylococcus spp. (15,0%), Micrococcus spp. (11,5%), Escherichia coli (10,7%) e Klebsiella spp. (10,7%). Observou-se uma maior ocorrência de bactérias Gram positivas seguidas por bactérias Gram negativas e fungos. A frequência de bactérias Gram negativas (28,4% do total de amostras coletadas) foi bastante representativa. Foram isolados 14 gêneros de bactérias, 03 gêneros de leveduras e 04 de fungos filamentosos. As 27 estirpes de E.coli isoladas apresentaram multirresistência aos antimicrobianos, sendo que ampiclina e amoxicilina+ácido clavulânico foram os antimicrobianos frente os quais observou-se maior índice de resistência (100%) por parte dos isolados, enquanto que cloranfenicol foi o antimicrobiano frente o qual observou-se maior índice de sensibilidade (100%). Somente um dos isolados de E.coli foi positivo para presença do gene codificador de fímbria S (sfa), podendo ser compatível com perfil de E. coli patogênica aviária (APEC) ou E. coli uropatogênica (UPEC). Nenhum dos isolados apresentou características condizentes com E.coli enteropatogênica (EPEC). Considerando-se a reduzida ocorrência dos genes codificadores de fatores de virulência estudados pode-se concluir que os passeriformes apreendidos do tráfico representam baixo risco potencial no tocante à transmissão de estirpes de EPECs, APECs e UPECs para outros animais ou mesmo para o ser humano. Por outro lado deve-se considerar o risco potencial de transmissão intra ou interespécies de E. coli multirresistentes aos antimicrobianos bem como a introdução destes micro-organismos no ambiente. Os riscos de disseminação de Salmonella spp., Cryptococcus spp e Candida spp. são pouco prováveis quando considerados programas de soltura. / Currently, many native bird species are considered rare in Brazil, once they are indiscriminately captured by animal traffickers and then are sold, which makes them increasingly found in smaller quantities in their natural habitats. Confiscated animals have been submitted to relocation programs attempting to ensure that they do not pose a risk to the native population. Wild passerines, healthy or sick, may carry a wide variety of microorganisms and therefore, knowledge on health status of confiscated animals which will be relocated, allows an assessment as to whether these animals act as carriers of pathogens to native populations as well as clarifies the epidemiology of diseases, which is fundamental to the preservation of animal and human health. This study aimed to investigate the occurrence and frequency of aerobic and facultative anaerobic bacteria and fungi in cloacal swabs of wild confiscated passerines which will be submitted to relocation programs. In vitro susceptibility testing of E. coli strains to differet antimicrobials as well as an investigation of the presence of virulence genes in these isolates using the polymerase chain reaction were performed. Most of the animals investigated (62.5%) presented a cloacal microbiota composed by aerobic and/or facultative anaerobic bacteria and/or fungi. The microorganisms most frequently isolated were: Staphylococcus spp. (15.0%), Micrococcus spp. (11.5%), Escherichia coli (10.7%) and Klebsiella spp. (10.7%). The frequencies of isolations of Gram positives bacteria were higher (P <0.05) than those of Gram negatives and also higher (P <0.05) than fungi. The frequencies of isolations of Gram negatives bacteria (28.4% from the total of samples) were very representative. Fourteen genera of bacteria, 03 genera of yeasts and 04 of filamentous fungi were isolated. The occurrence of multidrug resistance was observed for 100% of the E. coli isolates. All ,E. coli strains were resistant to ampicillin and amoxicillin plus clavulanic acid and were sensitive to chloramphenicol. One E.coli isolate was positive for the presence of the gene encoding S fimbriae (sfa), may be a strain profile compatible with UPEC or APEC. None of the E. coli isolates resembled EPEC. Considering the reduced occurrence of genes encoding virulence factors it was concluded that confiscated passerines represent low potential risk regarding the transmission of EPECs, APECs or UPECs strains to other animals or even humans. Furthermore, the potential risk of intra or interspecies transmission of E. coli multiresistant to antimicrobials must be considered as well as the introduction of these micro-organisms in the environment. The risks regarding dissemination of Salmonella spp., Cryptococcus spp and Candida spp. are unlikely when relocation programs are considered.

Habitat selection research has focused on the role of vegetative and geologic habitat characteristics or antagonistic behavioral interactions. Conspecifics can confer information about habitat quality and provide positive density-dependent effects that may result in improved fitness, resulting in positive behavioral responses to conspecifics as a habitat selection strategy. I conducted 3 replicated, manipulative experiments to investigate use of conspecific cues in habitat selection for the golden-cheeked warbler (Dendroica chrysoparia) using simulated conspecific vocalizations during pre-settlement and post-breeding periods, across a range of woodland canopy cover. I measured territory density, pairing, and fledging success in paired treatment and control units. Territory density was >2 times higher in treatment units across the range of canopy (P = 0.02). Pairing success was positively correlated with territory density (P = 0.008). Territory density response was higher for pre-settlement than post-breeding treatment (P = 0.004). I found pre-settlement and post-breeding conspecific cues influence golden-cheeked warbler habitat selection, inducing settlement in previously unoccupied areas, and producing aggregations within areas of similar vegetative characteristics. Better understanding of social information use in habitat selection can improve our understanding of species distributions, yielding more accurate predictive distribution models; improve our ability to predict impacts of habitat changes on habitat use, survival, reproduction, and ultimately fitness; and provide a potential tool for attracting individuals to restored or managed sites.