Migratory shorebirds are the most threatened avian species due to the effects of human activities and climate change. Physiological parameters are useful to evaluate the health status of free-living animals. Here we investigated lymphocytes, heterophils, heterophils/lymphocytes, and glucose for female and male Two-banded Plovers (Charadrius falklandicus Latham, 1790) during nonbreeding (body moult) and breeding (incubation) seasons in coastal areas of northern Patagonia, Argentina. We also measured corticosterone for the first time for this species during the breeding season. Nonbreeding Two-banded Plovers were more likely to have higher physiological measurements that were not dependent on body moult nor body condition, being similar between sexes. Differences found in glucose are likely related to recent feeding in nonbreeding birds compared with fasting during incubation. The gregarious nonbreeding behaviour in comparison with the isolated breeding pairs would increase the risk of acquiring parasites and (or) pathogens inducing a response of the immune system reflected in higher values of lymphocytes. Baseline corticosterone during breeding was similar between sexes and were lower compared with other values reported for breeding plovers. Two-banded Plovers undergo energetically demanding physiological changes during the nonbreeding stage, strengthening the idea that conservation of the environmental resources at these locations may be more important than previously thought.

El Nino Southern Oscillation events (ENSO) and the subsequent opposite weather patterns in the following months and years (La Nina) have major climatic impacts, especially on oceanic habitats, affecting breeding success of both land and sea birds. We assessed corticosterone concentrations from blood samples during standardized protocols of capture, handling and restraint to simulate acute stress from 12 species of Galapagos Island birds during the ENSO year of 1998 and a La Nina year of 1999. Plasma levels of corticosterone were measured in samples collected at capture (to represent non-stressed baseline) and subsequently up to 1 h post-capture to give maximum corticosterone following acute stress, and total amount of corticosterone that the individual was exposed to during the test period (integrated corticosterone). Seabird species that feed largely offshore conformed to the brood value hypothesis whereas inshore feeding species showed less significant changes. Land birds mostly revealed no differences in the adrenocortical responses to acute stress from year to year with the exception of two small species (<18 g) that had an increase in baseline and stress responses in the ENSO year - contrary to predictions. We suggest that a number of additional variables, including body size and breeding stage may have to be considered as explanations for why patterns in some species deviated from our predictions. Nevertheless, comparative studies like ours are important for improving our understanding of the hormonal and reproductive responses of vertebrates to large scale weather patterns and global climate change in general. (C) 2018 Elsevier Inc. All rights reserved.

Abstract ∙ We observed several individuals of a tropical fruiting tree, Topobea multiflora (Melastomataceae), to determine the diversity and prevalence of bird species that use this plant as a food source. Conducted on the south Pacific slope of Costa Rica, these observations are of interest because T. multiflora, though it grows in early successional habitat, attracts many bird species typically associated with mature forest. Most of these species are potential candidates for dispersing the small seeds of mature forest species as they leave the forest to feed on the fruit of T. multiflora. In this study, we recorded 477 observations of 24 species belonging to seven families feeding on T. multiflora fruit during ten count periods of observation. The family Thraupidae (tanagers) had both the highest proportion of feeding observations (65.8%) and the greatest diversity of all visiting taxa (13 species). The five species with the highest overall prevalence (prevalence >5%) were Silver‐throated Tanager (Tangara icterocephala), Cherrie’s Tanager (Ramphocelus costaricensis), Thick‐billed Euphonia (Euphonia laniirostris), Common Bush‐tanager (Chlorospingus ophthalmicus), and Bay‐headed Tanager (Tangara gyrola). Our results suggest that several species of Neotropical frugivores, because of their relationship to T. multiflora, may be considered indicator species of ongoing forest regeneration in southwestern Costa Rica. Resumen ∙ Observaciones de especies de aves alimentándose de frutos de Topobea multiflora en el sudoeste de Costa Rica Observamos varios ejemplares de árboles con frutos de la especie Topobea multiflora (Melastomataceae) para determinar la diversidad y prevalencia de las especies de aves que se alimentan de esta planta. Estas observaciones, realizadas en la pendiente sud‐Pacifica de Costa Rica, son de interés ya que T. multiflora, si bien crece en hábitats con disturbio o en regeneración, atrae muchas especies generalmente asociadas a bosques maduros. La mayoría de estas especies son candidatos potenciales para la dispersión de semillas de especies de plantas de bosques maduros cuando se alejan del bosque para alimentarse de los frutos de T. multiflora. En este estudio, registramos 477 observaciones de alimentación de frutos de T. multiflora, correspondientes a 24 especies pertenecientes a siete familias. La familia Thraupidae (tangaras) presento la mayor abundancia (341 observaciones) y la mayor riqueza de especies (13 especies). Las cinco especies con mayor prevalencia (> 5%) fueron: Tangara goliplateada (Tangara icterocephala), Tangara costarricense (Ramphocelus costaricensis), Eufonia piquigruesa (Euphonia laniirostris), Clorospingo común (Chlorospingus ophthalmicus) y Tangara cabecibaya (Tangara gyrola). Nuestros resultados sugieren que varias especies de aves frugívoras Neotropicales, debido a que frecuentan plantas de T. multiflora, podrían ser consideradas especies indicadoras de procesos de regeneración de bosques.

In the coevolutionary dynamic of avian brood parasites and their hosts, maternal (or transgenerational) effects have rarely been investigated. We examined the potential role of elevated yolk testosterone in eggs of the principal brood parasite in North America, the brown-headed cowbird, and three of its frequent host species. Elevated maternal androgens in eggs are a common maternal effect observed in many avian species when breeding conditions are unfavorable. These steroids accelerate embryo development, shorten incubation period, increase nestling growth rate, and enhance begging vigor, all traits that can increase the survival of offspring. We hypothesized that elevated maternal androgens in host eggs are a defense against brood parasitism. Our second hypothesis was that elevated maternal androgens in cowbird eggs are a defense against intra-specific competition. For host species, we found that elevated yolk testosterone was correlated with parasitized nests of small species, those whose nest success is most reduced by cowbird parasitism. For cowbirds, we found that elevated yolk testosterone was correlated with eggs in multiply-parasitized nests, which indicate intra-specific competition for nests due to high cowbird density. We propose experimental work to further examine the use of maternal effects by cowbirds and their hosts.

ABSTRACTArctic weather in spring is unpredictable and can also be extreme, so Arctic‐breeding birds must be flexible in their breeding to deal with such variability. Unpredictability in weather conditions will only intensify with climate change and this in turn could affect reproductive capability of migratory birds. Adjustments to coping strategies are therefore crucial, so here we examined the plasticity of the adrenocorticotropic stress response in two Arctic songbird species—the snow bunting (Plectrophenax nivalis) and Lapland longspur (Calcarius lapponicus)—breeding in northwest Greenland. Across the breeding season, the stress response was strongest at arrival and least robust during molt in male snow buntings. Snow bunting females had higher baseline but similar stress‐induced corticosterone levels compared to males. Modification of the stress response was not due to adrenal insensitivity, but likely regulated at the anterior pituitary gland. Compared to independent nestlings and adult snow buntings, parental‐dependent chicks had a more robust stress response. For Lapland longspurs, baseline corticosterone was highest at arrival in both male and females, and arriving males displayed a higher stress response compared to arriving females. Comparison of male corticosterone profiles collected at arrival in Greenland (76°N) and Alaska (67–71°N;) reveal that both species have higher stress responses at the more northern location. Flexibility in the stress response may be typical for birds nesting at the leading edges of their range and this ability will become more relevant as global climate change results in major shifts of breeding habitat and phenology for migratory birds. J. Exp. Zool. 323A: 266–275, 2015. © 2015 The Authors. J. Exp. Zool. published by Wiley Periodicals, Inc.

The 2013 Minamata Convention seeks to reduce anthropogenic emissions of mercury (Hg) and enhance public awareness of Hg exposure and impacts. The treaty also requires countries to increase monitoring of Hg in the environment in order to reduce human exposure and examine the efficacy of the treaty over time. Campos dos Goytacazes, Brazil, is located in a watershed with a history of significant Hg deposition from gold mining and sugarcane farming. This study provides previously unpublished data on the presence of Hg in certain fish in Campos and the awareness of mercury contamination among the local population. We analyzed Hg concentrations in five commonly consumed fish species by the residents of Campos and found concentrations to be elevated in some species, to vary significantly among species, and to correlate with trophic levels likely due to biomagnification. A sample survey of people in Campos found that education levels negatively correlated with knowledge of the presence of Hg in fish and the negative health effects of both Hg and heavy metal contamination in general. These findings have potential importance for understanding Hg levels in the environment, underscore the necessity for public awareness and education efforts regarding Hg contamination (as called for in the new Convention), and provide baseline measures for the presence of Hg in fish in Campos and public awareness related to this presence. These data can be compared to future studies to examine the efficacy of the Convention and other efforts to reduce Hg emissions and exposure to Hg in this part of Brazil.

Penguin colonies are highly visited worldwide. Although several studies have addressed how penguins behaviorally respond to tourist visitation at a point in time, nothing is known about their response across the entire breeding season. Furthermore, behavioral responses are driven by complex physiological processes and the basal physiological state of the individual might affect the way it responds to stimuli. To test the hypothesis that annual changes in corticosterone result from animals having different requirements for expressing (or not) the glucocorticoid-mediated behaviors at different times of the year in the context of tourist visitation, we examined circulating and stress-induced corticosterone in Magellanic penguins (Spheniscus magellanicus) from non-visited areas from the San Lorenzo colony, Peninsula Valdes, Argentina across the breeding season. We also examined the behavioral responses of penguins to a pedestrian approach in tourist-visited and non-visited areas of the colony across the season. Our results showed that circulating levels of corticosterone did not vary across the season; however, stress-induced corticosterone was lowest during molt. Our behavioral results showed that penguins displayed different behavior responses at varying distances depending on the area (visited or non-visited) and stage in the season. Penguins in the tourist area were more tolerant to a human approach than penguins in the non-tourist area. During settlement and molt, penguins showed higher occurrence of behaviors related to self-survival (such as standing, moving farther into the nest, and fleeing), whereas during incubation and chick rearing, penguins displayed mostly a behavior associated with defense and vigilance (such as alternate head turns). Furthermore, penguins allowed a closer approach during incubation, but elicited a subsequent behavior quicker than in the rest of the stages, suggesting that they would be particularly sensitive in this stage. Overall, our results suggest that corticosterone release across the season is more associated with penguins' survival in an extreme environment than with behavioral regulation. From a conservation perspective, we identified that penguins were more sensitive to human approach during incubation, but also molt should be considered as a vulnerable stage because corticosterone secretion is suppressed. (c) 2014 The Wildlife Society.

Increasing ecotourism activity in Argentine Patagonia has led to concerns about the effects of ecotourism on wildlife populations. Penguin breeding colonies are popular tourist destinations. While some species of penguins habituate to human visits, others exhibit negative effects due to disturbance. We studied the effects of tourism on Magellanic Penguins ( Spheniscus magellanicus ) at San Lorenzo colony located on the Peninsula Valdes, Chubut, Argentina. We measured behavioural, physiological, and reproductive parameters in birds nesting in tourist-visited and non-visited areas. San Lorenzo has 11 years of visitation history and a low intensity of visitors (~10,000 annually). After 15 min of a simulated tourist visit, penguins in the tourist area showed fewer alternate head turns and lower plasma levels of the stress hormone corticosterone than penguins in a non-visited area. However, penguins showed similar baseline levels of corticosterone between areas as well as similar levels of integrated corticosterone expressed after an acute stressor. Penguin breeding success and chick growth were similar between areas. We compared these findings to results previously published from Punta Tombo, a colony with a longer history (+50 years) and high intensity of annual visitors (>120,000 people). Many (reproductive and behavioural parameters), but not all (physiological parameters), of our findings are similar. That a physiological difference exists may suggest that the previous history of human visitation plays an important role in the response of the birds. Thus, the continuous monitoring of tourist activity is important, as a history of visitation disturbance seems to have an effect on how birds respond to tourists.

Using microsatellite markers and mitochondrial DNA (mtDNA) sequences (cytochrome oxidase 1 gene), we estimated levels of genetic structuring among nine Magellanic Penguin (Spheniscus magellanicus) colonies distributed throughout three major reproductive regions of the South Atlantic Ocean. Overall, breeding colonies showed relatively high levels of genetic diversity at both nuclear and mtDNA markers (mean heteorzygosity: H-e = 0.598; mean allelic diversity: A = 7.11; mtDNA haplotype diversity: h = 0.812). A hierarchical analysis of molecular variance based on microsatellite data showed limited genetic structuring of breeding colonies, with 99% of the variation explained by differences among individuals and 0.7-1.0% attributed to differences among the three regions. The mtDNA analysis revealed higher levels of genetic structuring, with 3.43% of the variation explained by regions and 2.24% explained by colonies within the regions. Furthermore, a Mantel test revealed a significant association between geographic and genetic distances among colonies. The limited genetic structuring we detected is likely a result of (1) population intermixing through natal dispersal and (2) the large effective sizes of the reproductive colonies, both of which prevent genetic differentiation at neutral markers, balanced with (3) the regional association of breeding colonies to distinct feeding grounds and (4) a recent expansion of the population. Our results suggest that the demographic dynamics of breeding colonies of Magellanic Penguins may be framed under a metapopulation model, in which colonies with large numbers of breeding pairs could be considered "source" populations for maintaining the overall abundance of this species in the Atlantic Ocean. Received 9 July 2007, accepted 11 November 2008.

How human activities affect the breeding and survival of avian populations. is of concern to wildlife biologists. While behavior and abundance studies can document change, it is also important to determine what physiological mechanisms drive the patterns of demographic change observed in bird populations affected by human activities. Here we review studies examining how the endocrine stress physiology of adult and chick Magellanic Penguins (Spheniscus magellanicus) is modified by tourist visitation. In a colony that shows few obvious negative behavioral or other population-level effects due to human disturbances, we describe some potentially significant physiological modifications that may occur because of visitation. While the long-term consequences of these physiological modifications remain unknown, they raise concerns that there may be negative impacts due to tourist visitation.

The neuromodulator serotonin is an important regulator of aggressive behavior in vertebrates. Experimentally increasing synaptic levels of serotonin with fluoxetine, a selective serotonin reuptake inhibitor, has been shown to reliably decrease the expression of aggressive behavior. Here, we describe a method by which fluoxetine can be noninvasively administered to male Betta splendens (an attractive model for the study of aggressive behavior) and describe a simple laboratory exercise that allows students to experimentally investigate the physiological mechanisms of aggressive behavior. We demonstrate that relatively short-term exposure (3 h) of male bettas to as little as 3 microg/ml of fluoxetine-treated aquarium water is sufficient to reduce the expression of specific aggressive behaviors. We emphasize the physiological concepts that can be addressed with this exercise, including the role of the serotonergic system in regulating aggression, and the interplay of environmental contaminants and physiology in regulating the expression of behavior. We also highlight important aspects of experimental design. This exercise can be flexibly altered to accommodate one or several laboratory periods. It is also low cost, is low impact to the animals, and requires minimal preparation time for instructors.

Ecotourism is increasing worldwide; hence, it is important to know how wildlife are affected behaviorally and physiologically by human visitation. We studied the effects of human visitation on the Magellanic Penguins (Spheniscus magellanicus) at Punta Tombo, Argentina, by monitoring changes in defensive head turns and plasma corticosterone (a hormone secreted in response to stress) for penguins with and without a history of tourist visitation. Habituation to human visitation was rapid. In penguins with no previous exposure to tourists, the number of defensive head turns and level of plasma corticosterone decreased significantly within 5 days of one 15-minute visit/day. Penguins living in tourist-visited and undisturbed areas secreted more corticosterone when captured and restrained than penguins visited by a person. Penguins in tourist areas, however did not show as strong a corticosterone response to capture and restraint as did penguins in areas without tourists. This difference was due to a decreased capability of the adrenocortical tissue to secrete corticosterone in tourist-visited birds. Although our data show no direct negative effects of tourism on Magellanic Penguins at Punta Tombo, consequences of a modification of physiological capabilities (e.g., adrenocortical function) may not become apparent until much later in life. The physiological differences between tourist-visited and undisturbed groups of Magellanic Penguins emphasize the importance of monitoring the effects of anthropogenic disturbances on wildlife at multiple levels.

We examined how the glucocortical stress response in free-living Magellanic penguin (Spheniscus magellanicus) chicks changes with age and whether adrenocortical function of chicks within a brood varies in relation to food provisioned by adults. Chicks showed little corticosterone response to capture stress shortly after hatching, an intermediate response around 45-d posthatch, and a robust stress response near fledging. However, in response to an adrenocorticotropic hormone (ACTH) challenge, hatchlings were capable of secreting corticosterone at adult-like levels. The larger sibling in broods of two showed a similar gradual stress-response development pattern. In contrast, by day 45, when differences in body condition were well established between siblings, the smaller, food-deprived chicks significantly increased baseline levels of corticosterone but showed normal stress-induced levels. Near fledging, baseline levels had returned to normal, but stress-induced levels were lower than expected. Similar to altricial species, normally developing semialtricial Magellanic penguin chicks do not express a robust corticosterone stress response until near fledging. Chronic stressors such as food deprivation cause corticosterone use to be up-regulated earlier than expected. However, in cases of extended chronic stress, down-regulation may ensue, thus avoiding the negative effects of chronically elevated levels of corticosterone.

Abstract:  Studies examining anthropogenic effects on wildlife typically focus on adults and on behavioral responses rather than the physiological consequences of human disturbances. Here we examined how Magellanic Penguin ( Spheniscus magellanicus) chicks living in either tourist‐visited or undisturbed areas of a breeding colony were affected by human visitation by comparing the baseline and stress‐induced levels of corticosterone during three periods of the breeding season. Newly hatched chicks in visited areas had higher corticosterone stress responses than newly hatched chicks in undisturbed areas (p =0.007), but baseline levels were similar (p =0.61). By 40–50 days of age and around fledging time, both visited and undisturbed chicks showed a robust corticosterone stress response to capture. Tourist‐visited chicks did not flee when approached by humans, however, whereas undisturbed chicks fled significantly sooner (i.e., when approached no closer than 9 m; p < 0.0001). Although it is unknown whether Magellanic Penguin chicks raised in visited areas suffer negative consequences from the elevation of the corticosterone stress response at hatching, they do exhibit behavioral habituation to human contact by the time they are ready to fledge. Unlike adults living in tourist areas, however, fledging chicks in visited areas do not have a decreased stress response to capture and restraint. Our results show that the coupling of behavioral and physiological habituation in Magellanic Penguins is complex and life‐history context may greatly affect the ability of wildlife to adapt to anthropogenic disturbances.

Field endocrinology techniques allow the collection of samples (i.e., blood, urine, feces, tissues) from free-living animals for analysis of hormones, receptors, enzymes, etc. These data reveal mechanisms by which individuals respond to environmental challenges, breed, migrate and regulate all aspects of their life cycles. Field endocrinology techniques can also be used to address many issues in conservation biology. We briefly review past and current ways in which endocrine methods are used to monitor threatened species, identify potential stressors and record responses to environmental disturbance. We then focus on one important aspect of conservation: how free-living populations respond to human disturbance, particularly in relation to ecotourism. Breeding adult Magellanic penguins, Spheniscus magellanicus, appear to habituate well to tourists, and breed in an area where about 70,000 people visit during the season. Baseline levels of corticosterone return to normal after exposure of naïve birds to humans. However, penguin chicks appear to show a heightened adrenocortical response to handling stress in nests exposed to tourists, compared to chicks living in areas isolated from human intrusions. Given that developmental exposure to stress can have profound influences on how individuals cope with stress as adults, this potential effect of tourists on chicks could have long-term consequences. This field endocrine approach identified a stressor not observed through monitoring behavior alone.