Although many penguin species migrate during the non‐breeding period, Gentoo Penguins Pygoscelis papua are year‐round residents. Despite being characterized as inshore feeders, the at‐sea spatial ...usage of Gentoo Penguins during the non‐breeding period, when central place foraging constraints are relaxed, is poorly understood. Here, we tracked the movements of Gentoo Penguins from five breeding colonies at the Falkland Islands, globally one of the largest Gentoo Penguin breeding populations. Gentoo Penguin movement patterns during the non‐breeding period were complex, which likely reflects a high degree of foraging plasticity. Specifically, considerable individual variation existed in foraging trip distance, duration and fidelity to deployment location. For example, maximum foraging trip distance for individual penguins ranged from 64 to 600 km from the colony location (or 480 km from the nearest point on land), and maximum foraging trip duration ranged from 5.7 to 24.8 days. Gentoo Penguin foraging trip distance and duration at the Falkland Islands far exceeded those reported at other locations during the non‐breeding period, and challenge the inshore, diurnal feeding stereotype. Gentoo Penguins also frequently moved between breeding colonies within the Falkland Islands archipelago, but typically returned to their respective colonies, although not necessarily on consecutive foraging trips. Extended movements highlight Gentoo Penguin breeding dispersal capability, which might play a crucial role in population dynamics and gene flow.
Human-produced noise, from transport, urbanization and industry, is widespread. Studies of noise pollution show a wide range of effects on birds, such as alterations in communication, parental ...behaviour, physiology and reproductive success. These human-induced changes are likely to have long-term impacts, such as altered nestling physiology and survival, as well as reduced local population size. Further experimental field studies that simultaneously investigate the effects of noise exposure on avian behaviour, physiology and reproductive success are needed. Here, we used an experimental field study to investigate impacts of short-term traffic noise exposure on parental behaviour (i.e. vigilance and feeding rate), nestling body size and oxidative stress (as measured by oxidative status) and nestling fledging success in tree swallows, Tachycineta bicolor. Our results show negative consequences of traffic noise exposure, despite a relatively modest playback regime (6h, every other day). Adults in noise-exposed territories were less vigilant earlier in the nestling period and fed at a higher rate later in the nestling period, compared to controls. However, increased feeding rate in noise-exposed nests did not compensate for noise impacts on nestlings: noise-exposed nestlings were smaller and had higher oxidative status, compared to control nestlings. Noise-exposed nestlings took longer to fledge, but we found no effect of noise on fledging success. These results highlight the potential long-term consequences of short-term noise exposure (decreased nestling size and increased oxidative status) and add to a growing body of literature, showing that noise pollution can negatively impact birds through both direct and indirect pathways.
•Tree swallow nestlings and adults were exposed to traffic noise during breeding.•Noise-exposed nestlings had decreased body size and increased oxidative stress.•Noise exposure caused delayed fledging, but no difference in nestling survival.•Negative nestling impacts are not explained by differences in parental behaviour.•Our results suggest direct noise effects on nestlings.
The current study investigated the correlation among sperm production (milt volume, spermatocrit and sperm count), sperm motility characters and biochemical composition of seminal plasma during ...different seasons to estimate the quality of semen in the Spotted scat (Scatophagus argus). The sperm of 120 males were collected over a period of 2 years seasonally viz., summer, pre-monsoon, monsoon and post-monsoon. During the collection period, it was observed that there were significant (p < 0.05) seasonal variations in the semen quality including sperm motility and production more in the summer season than other seasons. The osmolality of seminal plasma varied from 343.33 to 370.33 mOsm/kg. The pH of seminal plasma elevated from 7.37 to 7.63 during monsoon and summer seasons. The motility of S. argus sperms correlated with the concentration of biochemical compounds viz., Ca2+, Mg+ and Cl− during the summer season. Based on the present observation it could be highlighted that sodium and potassium were negatively correlated (p < 0.01 and p < 0.05) effect on total protein (r = −0.826; −0.956), glucose (r = −0.819; −0.717), cholesterol (r = −0.978; −0.849), AST (r = −0.853; −0.897), ALT (r = −0.970; −0.967), calcium (r = -0.850; −0.697), magnesium (r = −0.852; −0.843) and chloride (r = −0.906; −0.926). In conclusion, many physical and biochemical compositions of S. argus semen improved during that the summer and pre-monsoon season as compared to that of monsoon and post-monsoon. Fertility tests were performed to determine the ability of spermatozoa to fertilize an egg. Highest fertilization (79.92 ± 4.60%) and hatching (80.75 ± 3.89%) rates were observed during summer, while the rates were lowest during monsoon (40.50 ± 4.52%; 53.92 ± 7.38%). This work forms a compiled data for standard semen quality, which in turn will help to select good milters for hatchery production, cryopreservation and assisted breeding programs of this fish.
•Seasonal wise physical & biochemical composition of milt quality evaluated in Scatophagus argus.•Milt samples from 120 males were collected over a period of 2 years at four seasons.•The milt quality of S. argus were improved in summer and pre-monsoon as compared to monsoon and post-monsoon months.
In the last decades, the assumption that complex social life is cognitively challenging, and thus can drive mental evolution, has received much support from empirical studies in nonhuman primates. ...While extending the scope to other mammals and birds, different views have been adopted on what constitutes social complexity and which specific cognitive skills are selected for. Notably, many avian species form “open” groups as non-breeders (i.e., seasonally and before sexual maturity) that have been largely ignored as potential sources of social complexity. Reviewing 30 years of research on ravens, we illustrate the socio-ecological conditions faced by these birds as non-breeders and discuss how these relate to their socio-cognitive skills. We argue that the non-breeding period is key to understand raven social life and, to a larger extent, avian social life in general. We furthermore emphasize how the combination of the large-scale perspective (defining social system components: e.g., social organization, mating system) and the individual-scale perspective on social systems allows to better capture the complete set of social challenges experienced by individuals throughout their life, ultimately resulting on a more comprehensive understanding of species’ social complexity.
Migrating animals show remarkable diversity in migration strategies, even between individuals from the same population. Migrating longer distances is usually expected to be costlier in terms of time, ...energy expenditure and risks with potential repercussions for subsequent stages within the annual cycle. Such costs are expected to be balanced by increased survival, for example due to higher quality wintering areas or lower energy expenditure at lower latitudes. We compared reproductive parameters and apparent survival of lesser black-backed gulls (
) breeding in The Netherlands, whose winter range extends from the UK to West Africa, resulting in one-way migration distances that differ by more than 4500 km. Individuals migrating furthest arrived later in the colony than shorter distance migrants, but still laid in synchrony with the colony and consequently had a shorter pre-laying period. This shorter pre-laying period affected neither egg volumes nor hatching success. We found no relationship between migration distance and apparent survival probability, corresponding with previous research showing that annual energy expenditure and distance travelled throughout the year is similar across migration strategies. Combined, our results indicate an equal fitness payoff across migration strategies, suggesting there is no strong selective pressure acting on migration strategy within this population.
Most studies focusing on Rock Sparrow populations concern their breeding biology. With this study, we aim to investigate the wintering habitat and social behaviour outside the breeding period. In the ...study area the species is present all year long, and, outside the breeding period, birds frequently gather together on flocks of different size (3-150 individuals), which are larger in the coldest months. The habitat types most used by the species were cereal fields with crops in their first stage of development (17.71% ± 4.72 Standard Deviation) and arable stubbles, both of them with bushes and trees on their boundaries (82.4%), which likely provide shelters from predators. The bird species most frequently associated with Rock Sparrow flocks were Tree Sparrow, Starling and Crested Lark. Holes in the roof tiles of the same abandoned buildings used for breeding were also used as night shelters. The average hours of leaving and returning to the shelters was strictly related to the photoperiod (rs = -0.9405; 0.8810).
Yellow Warblers (Setophaga petechia) are abundant breeding birds in North America, but their migratory and non-breeding biology remain poorly understood. Studies where genetic and isotopic techniques ...were used identified parallel migration systems and longitudinal segregation among eastern- and western-breeding populations of Yellow Warblers in North America, but these techniques have low spatial resolution. During the 2015 breeding season, we tagged male Yellow Warblers breeding in Maine (N = 10) and Wisconsin (N = 10) with light-level geolocators to elucidate fine-scale migratory connectivity within the eastern haplotype of this species and determine fall migration timing, routes, and wintering locations. We recovered seven of 20 geolocators (35%), including four in Maine and three in Wisconsin. The mean duration of fall migration was 49 d with departure from breeding areas in late August and early September and arrival in wintering areas in mid-October. Most individuals crossed the Gulf of Mexico to Central America before completing the final eastward leg of their migration to northern South America. Yellow Warblers breeding in Maine wintered in north-central Colombia, west of those breeding in Wisconsin that wintered in Venezuela and the border region between Brazil, Colombia, and Venezuela. Our results provide an example of crosswise migration, where the more easterly breeding population wintered farther west than the more westerly breeding population (and vice versa), a seldom-documented phenomenon in birds. Our results confirm earlier work demonstrating that the eastern haplotype of northern Yellow Warblers winters in northern South America, and provide novel information about migratory strategies, timing, and wintering locations of birds from two different populations. Setophaga petechia es un ave abundanteque se reproduce en América del Norte, pero su biología durante la migración y epoca reproductiva sigue siendo poco conocida. Los estudios en los que se utilizaron técnicas genéticas e isotópicas identificaron sistemas de migración paralelos y segregación longitudinal entre las poblaciones de S. petechia que se reproducen en el oriente y occidente en América del Norte, pero estas técnicas tienen baja resolución espacial. Durante la temporada reproductiva del 2015, colocamos geolocalizadores de nivel de luz en machos de S. petechia en Maine (N — 10) y Wisconsin (N = 10) para dilucidar la conectividad migratoria a escala fina dentro del haplotipo oriental de esta especie y determinar el momento de migración durante el otoño, rutas y lugares donde pasan el invierno. Recuperamos siete de 20 geolocalizadores (35%), incluidos cuatro en Maine y tres en Wisconsin. La duración media de la migración de otoño fue de 49 días. Con salida de las áreas de repducción a finales de agosto y principios de septiembre y llegada a las zonas de invierno a mediados de octubre. La mayoría de los individuos cruzaron el Golfo de México a América Central antes de completar la etapa final hacia el este de su migración al norte de América del Sur. Los individuos de S. petechia que se reproducen en Maine pasaron el invierno en el centro-norte de Colombia, al oeste de los que se reproducen en Wisconsin y que en invieno estuvieron en Venezuela y en la región fronteriza entre Brasil, Colombia y Venezuela. Nuestros resultados proveen un ejemplo de migración cruzada, donde la población reproductiva más oriental paso el invierno más hacia el oeste que la población reproductiva más occidental (y viceversa), fenómeno que rara vez se documenta en las aves. Nuestros resultados confirman los trabajos anteriores que demuestra que el haplotipo oriental de S. petechia del norte pasa el invierno en el norte de América del Sur, y proporciona información novedosa sobre las estrategias migratorias, tiempos y ubicaciones en invierno de las aves de las dos poblaciones.
Diet during the non‐breeding period influences condition and subsequent reproduction. Physiological mechanisms underlying such carry‐over effects are poorly understood but could be clarified by ...studying physiological responses to variation in diet during non‐breeding. The hormone corticosterone provides a functional link between diet and survival and reproduction, but methodological limitations have prevented previous studies from testing the hypothesis that, on an individual level, avian corticosterone levels during the non‐breeding period reflect broader patterns in feeding ecology during that time. Using museum specimens (1859–2002) and live birds (2012), we found that corticosterone from feathers (CORTf) is negatively related to trophic position (TP) inferred from feather stable‐nitrogen isotope values (δ¹⁵N) in Leach's Storm‐petrels Oceanodroma leucorhoa. CORTfwas not related to stable‐carbon isotope values (δ¹³C). We detected no temporal trends in CORTfor δ¹⁵N, and neither was related to a large‐scale index of winter climate, suggesting a general ecological phenomenon rather than a reflection of historical environmental changes. However, we detected a temporal trend in feather δ¹³C, and δ¹³C was related to δ¹⁵N. Our findings suggest a physiological benefit of feeding at higher TPs, either through increased nutritional value or reduced foraging costs associated with higher TP prey, and future research should aim to distinguish between these two explanations. Nevertheless, ours is the first evidence of a correlation between individual endocrine levels and foraging ecology, and demonstrates non‐lethal variation in a physiological mediator in turn related to variation in resource use.
•Minimum landing size is above maturity size.•A female of S. arctus can spawn up to three consecutive times a year.•S. arctus has a long, continued reproductive and breeding period in the NE ...Atlantic.•The prohibition to fish ovigerous females leads to a bias towards capturing males.
This work addresses the study of a population of the slipper lobster S. arctus in the Galician coast (NE Atlantic), where a decrease in the exploited stock has been observed in the last decades, as has occurred in other populations of this species throughout its geographical distribution range. In spite of this fact and of its high commercial value, the management of its fishery relies on poor knowledge of relevant biological aspects such as its reproductive biology. For this purpose, monthly sampling has been carried out between February 2008 and June 2009 to characterize the reproductive cycle, breeding cycle, and sexual maturity size of S. arctus in the study area. The obtained results are particularly interesting to attempt to improve fishery management. On one hand, the current regional minimum landing size (90 mm total length; 30 mm cephalothorax length, CL) has been demonstrated to allow newly sexually mature individuals—regardless of which sexual maturity criterion is applied (females: 16.3–25.7 mm CL; males: 16.3–25.8 mm CL)—to reproduce at least once. On the other hand, the long breeding cycle observed in the area, with presence of ovigerous females throughout the whole year except for October and with values over 50% for 7 months a year (between February–August), along with the prohibition to catch ovigerous females, makes the fishery highly biased towards males, and the reproductive potential of the stock could therefore be affected.
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