Breeding dispersal movements of Dupont’s Lark Chersophilus duponti in fragmented landscape

Summary Understanding patterns of dispersal behaviour of threatened species is important in conservation biology and population ecology, especially in fragmented landscapes. Dupont’s Lark Chersophilusduponti is a threatened passerine whose European population has declined by around 40% in the last decade. To study natal and breeding dispersal of the species, we used a long-term mark-recapture dataset (2011–2019) and analysed the records of 32 males (39 dispersal movements) and five females (five dispersal movements) captured during the breeding season at Rincón de Ademuz (Valencia, eastern Spain). Adult birds had a median breeding dispersal of 154 m (Q25-Q75 = 70.0–300.3). Among these captures, two adult males dispersed to a new patch of habitat separated by more than 5,800 m. Only one out of 26 nestlings ringed was trapped as an adult bird, which occurred at a site different from the natal territory (4,500 m). Our results show a low breeding dispersal for the species and are, in essence, in agreement with previous studies carried out in the Ebro Valley metapopulation, one of the core areas for the species in Europe. Nonetheless, unlike in the Ebro Valley, we detected movements of adult birds between habitat patches. The low recovery rate of young birds suggests that they left their natal sites and moved outside the study area or that their survival rate was very low. Future studies focused on the post-fledging survival rate and natal dispersal movements are essential to determine effective conservation measures for the species. Habitat management actions in occupied and potential sites should be carried out close to the areas inhabited by the species to increase the success rate of the interventions and the effective dispersal and therefore population connectivity.

Carryover effects of long-distance avian migration are weaker than effects of breeding environment in a partially migratory bird

Migration may expose individuals to a wide range of increasing anthropogenic threats. In addition to direct mortality effects, this exposure may influence post-migratory reproductive fitness. Partial migration—where a population comprises migrants and residents—represents a powerful opportunity to explore carryover effects of migration. Studies of partial migration in birds typically examine short-distance systems; here we studied an unusual system where residents breed in mixed colonies alongside long-distance trans-Saharan migrants (lesser kestrels (Falco naumanni) in Spain). Combining geolocator data, stable isotope analysis and resighting data, we examined the effects of this stark difference in migratory strategy on body condition, breeding phenology and breeding success. We monitored four colonies in two regions of southern Spain for five consecutive years (2014–2018), yielding 1962 captures, determining migratory strategy for 141 adult bird-years. Despite a 3000-km difference in distance travelled, we find no effect of strategy on breeding parameters. We find weak evidence for a short-term negative carryover effect of migration on body condition, but this was only apparent in the breeding region with lower primary productivity. Our results indicate that carryover effects of even highly divergent migratory strategies may be minimal relative to effects of conditions experienced on breeding grounds.

Age dynamics of the stomach and intestines’ anatomical parameters of the budgerigar (Melopsittacus undulatus)

The object of research was the morphofunctional organization of the stomach and intestinal of the budgerigar (Melopsittacus undulatus) in the postnatal period of ontogenesis. The aim of the work was to determine the age topography and anatomical structure characteristics of the stomach and intestines from the budgerigar (Melopsittacus undulatus). The material for morphological studies was selected from budgerigars of 9 groups: 1-, 3-, 7-, 14-, 21-day-old, 1-, 2-, 6-month-old and 1-year-old (n = 5). The absolute bodyweight of parrots and their organs was determined using a ВЛКТ-500 balance and a «Techniprot Waga Torsyjna-WT 500» torsion balance. Linear indicators of organs were determined using a ruler (GOST 17485-72) and a calliper (GOST 166-89). According to the research results, it was found that the increase in body weight of parrots during the first year of life was uneven. In the first month, it was increased by 15.3 times, in the second month – by 1.1 times. During the first month, it was increased most intensively in the first week. Parrots reached the mass of an adult bird at the age of 2 months. During the first year of life, the greatest body weight was established at the age of 6 months, and the greatest absolute weight, linear indicators of the glandular and muscular parts of the stomach, as well as the intestines – at the age of 21 days. The glandular stomach of the budgerigar reached the highest relative weight indicators at the age of 3 days, and the muscular part of the stomach and intestines – at the age of 7 days. The length of the intestine increased most intensively in the first week of life. During the first year of life, the relative length of the budgerigars small intestine gradually decreased. The greatest indicators of the duodenal absolute length were established at the age of 60 days, lean – 60 days, ileum – 21 days. The greatest indicators of the duodenal relative length were established at the age of 30 days, jejunum – 7 days, ileum – 14 and 21 days. High linear indices, as well as indices of the stomach and intestines mass of budgerigars, indicated their key importance in providing the body with nutrients and biologically active substances during intensive growth.

Osprey observed when drowned by its prey

An Osprey Pandion haliaetus was observed by eight people as it was dragged under water by a fish and drowned. Several unsuccessful attempts to leave the water surface caused the Osprey gradually to sink in the water until it disappeared. The area was searched by boat, but the fish and Osprey were gone, and it was confirmed that there were no fishing nets in the area. This is a rare event, and sometimes rejected by scientists. The good view by eight persons, and detailed descriptions I received from two independent observers make the observation credible. The Osprey was an adult bird. In addition to traditional explanations that claws can become fastened to scales, bones or flesh of the fish, I propose that muscle spasm may be a reason why the osprey was not able to release its grip. Cover illustration: Fishing Osprey. Photo: Jørn Bøhmer Olsen.

Seasonal rainfall in subtropical montane cloud forests drives demographic fluctuations in a Green-backed Tit population

Montane birds are vulnerable to climate change. However, the mechanisms by which weather drives demographic processes in montane birds have seldom been investigated. We conducted a long-term study (2009–2019) on the Green-backed Tit (Parus monticolus), an insectivorous passerine, in the montane cloud forest of subtropical Taiwan. We explored the effects of weather variability on the productivity and survival of adult Green-backed Tits. Nest survival was negatively associated with seasonal rainfall during the breeding season (April–July) and was lower in early clutches than in late clutches. Higher typhoon-induced precipitation during the postbreeding period (July–September) was related to reduced adult survival, but neither summer temperature nor winter weather conditions were found to be related to adult bird survival. We developed a stochastic simulation model for Green-backed Tit population dynamics based on empirical data. We compared the simulated time-series and observed population growth rates (λ) and found that 80% (8/10 yr) of the observed λ fell within the 5th and 95th percentiles of the simulated data over the 10-yr period. Moreover, the simulated average (± standard deviation) of the geometric mean of λ over 10 yr (1.05 ± 0.07) was close to that observed from 2009 to 2019 (0.99), which provided confidence that the model effectively simulated the population growth rate of the Green-backed Tit. We conducted a sensitivity analysis for λ and found that juvenile and adult survival influenced by typhoon-induced rainfall were the greatest contributors to the variance in the growth rate of the Green-backed Tit population. With the onset of intensified seasonal precipitation associated with global warming, the population growth and density of Green-backed Tits will decline substantially. Our results suggest that under scenarios of high emissions of greenhouse gas, this local population of Green-backed Tits will not persist in the near future.

Efficiency of using SNP markers in the MSTN gene in the selection of the Pushkin breed chickens

In the poultry industry, indicators reflecting the growth rate of young stock and the exterior characteristics of chickens are important benchmarks for breeding. Traditional selection based on phenotypic evaluation is characterized by low efficiency with a low character inheritance ratio and is difficult to apply in small groups of animals and birds bred in bioresource collections. The use of molecular genetic markers associated with economically important traits makes it possible to carry out early selection of birds. This entails an increase in the profitability of the poultry industry. Recently, single nucleotide polymorphisms (SNPs) have served as convenient markers for selection purposes. For five generations (P1–P5), an experimental selection of hens of the Pushkin breed was carried out for live weight. It was based on selection for single nucleotide polymorphism rs313744840 in the MSTN gene. As a result, a significant increase in the frequency of allele A in this gene, from 0.11 to 0.50, took place. The association of SNP markers with meat qualities in the experimental group led to changes in the exterior profile of an adult bird at 330 days of age. The individuals with the AA and AG genotypes had the greatest live weight and longest body. As a result of selection, the bird on average became larger due to an increase in the number of heterozygous individuals with long bodies and large chest girths. The depth of the chest and the width of the pelvis increased due to an increase in the frequency of allele A in the experimental population. A tendency towards an increase in these indicators with the substitution of G with A in the genotype was found. Saturation of the population with desirable alleles led to an increase in the average live weight of the chickens. Analysis of the exterior parameters of adult birds showed that this growth is achieved by increasing the depth and volume of the bird body, and not by increasing the length of the limbs. Thus, marker selection carried out for five generations in the experimental population of Pushkin breed chickens to increase body weight has reliably (p < 0.001) changed the exterior profile of adult birds.

Age features of topography and number of intestinal endocrinocytes in domestic duck

The aim of the study was to determine the features of the topography and the number of the total population of endocrinocytes and enterochromaffin cells in the intestines of ducks during the first year of the postnatal period of ontogenesis. The experiments were performed on domestic ducks (Anas platyrhynchos domesticus) of black white-breasted breed (n = 5) 9 groups: 1-, 3-, 7-, 14-, 21-days-old, 1-, 2-, 6-month-old and 1-year-old. Determination of the total population of endocrine cells (argyrophilic) and enterochromaffin (argentaffin) was performed on histological specimens made from cross-sections of the middle section of the duodenum, jejunum, ileum, cecum and rectum, stained by Masson and Grimelius. The endocrine cells of 1- and 3-days-old ducks had a «superficial» location due to insufficient formation of crypts and villi. In older birds, in the duodenum, jejunum, and ileum, both argyrophilic and argentaffin APUD cells were localized mainly in crypts, and in the cecum and rectum, they were also in the epithelial layer of the villi. During the entire observation period, the highest content of both argyrophilic and argentaffin endocrinocytes in all intestines were found in 21-days-old ducks. Already at 3-days-old age, the total number of endocrine cells in various intestines corresponded to those of an adult bird. The highest number of argyrophilic and argentaffin endocrinocytes was found in the ileum and cecum, less in the rectum and jejunum, and the smallest number was in the duodenum. Enterochromaffin cells are the most common type of endocrinocytes in the ducks’ intestines, their relative content ranged from 40.1 to 97.5%. The highest relative content of argentaffin cells at 1-, 3- and 7-day-old was observed in the duodenum, at 14-day-old – in the duodenum and colon, at 21-day-old – in the rectum, at 1- and 2-month-old in jejunum, at the age of 6 month – in the duodenum, jejunum and caecum, and at the age of 1-year-old – in the ileum and cecum. In addition to argyrophilic endocrinocytes, which were located in the epithelium, other cells were found in the loose connective tissue of the villi base, the cytoplasm of which was also intensively impregnated with silver nitrate. Such cells were smaller and mostly oval in shape. Their cytoplasm was impregnated almost evenly around the nucleus and had no polarity in the location of the granules. Probably those were mast cells, which also contain bioamines, and, as well as enteroendocrinocytes, are found in the argyrophilic reaction.

How Birds and Other Adults Get Their Color Back

Lorenz's Kinderchenschema can lead to genetic repurposing (pleiotropy) as mutations that help infants survive are later used for adult mating. Around 2014 it was discovered that blue eyes and blond hair appeared first among human infants. Color attracts, essential for infant mammal survival. Pleiotroptic regulators were selected to enable these attribute to be retained in adults, as attraction capacity also increases mating success.Nestlings birds have beaks with internal membranes called gapes, frequently colorful and/or patterned. Beaks conserve vital genetic information, useful over 30 million years of radiation. Colorful gapes are present in monochromatic as well as species with colorful plumage. Gapes and the beak's cere are the only colored part of many raptors, a broad group related to ancestors of many landbirds. Gapes are bird Kinderchenschema, an infant display feature that compels parent behavior.Birds move in extradimensional space, with bifurcated visual systems that lets one side control flight in the face of distraction. Bright, bold displays aid navigation. Ecological psychology, developed for pilot training, established motion perception as the core of direct perception. Bird gapes serve as landing pads.Mammalian Kinderchenschema is dominated by superficial features of the head, such as eye and forehead size, to transact emotion that encourages protection and feeding. Atricial bird kinderchenschema also promotes protection and feeding. When nestlings are vulnerable to predation, internal mouth color remains hidden, protecting them. When nestling parents approach, the internal mouth color is exposed, enabling feeding.For a nestling color to be repurposed in plumage, it may trigger a conditioned response that aids selection. Nestling displays trigger adult bird neurotransmitters. Color can be disassociated from underlying structure and transferred, along with hormone release.There's a strong correlation between gape and plumage color. Adaptionist explanations of gape and feather colors emphasize nutrient conditions, but these increase saturation, not brilliance. It is color's attention-grabbing aspect that makes it so important for nestlings, and transferable for mating. Given changing environments, that require birds to evolve different color displays, the conserved resource of gape color is important.

What have we recently learned about song learning and social interactions?

Vocal learning in birds is a complex animal behavior with several parallels to vocal learning in humans. Early experiments in the 70s showing that juvenile birds could learn their species’ normal song presented only through loudspeakers led to the general notion that social interactions are unnecessary for song learning. These views were soon challenged, and after decades of research we know that different social factors influence song learning. Here, I discuss recent research that is getting us closer to understanding how. Juvenile birds in the wild are exposed to both direct and indirect interactions with singing adults, which can be relevant to different aspects of the learning process. The exposure to a potential living tutor may trigger or enhance the learning process, but direct interaction with a tutor producing the song type that is finally learned or incorporated to the repertoire is not required. Social interactions that the learner witnesses may be more important in determining which songs are included in the final repertoire of an adult bird. Further research is also required to better understand the role of interactions with females, not by providing a model song to imitate but by exhibiting responses contingent to juveniles practicing their songs.

Mass fluctuation in breeding females, males, and helpers of the Florida scrub-jay Aphelocoma coerulescens

Much evidence suggests that birds actively regulate their body mass reserves relative to their energy needs. Energy requirements during reproduction may differ in relation to sex-specific behavioural roles or, in the case of cooperative breeders, breeders relative to helpers. We measured body mass of free-living Florida scrub-jays throughout the nesting season by training them to land on an electronic balance. Jays exhibited a pattern of diurnal linear mass gain, from morning to afternoon. Day-to-day mass fluctuations, defined as the difference between mass on two consecutive days, were small (>80% were within 2 g, less than 3% of the mass of an adult bird) for all classes of jays: female breeders, male breeders and prebreeding helpers. The jays, which live in subtropical south-central Florida, did not exhibit changes in day-to-day mass fluctuation relative to weather or climate variables or calendar date. Day-to-day mass fluctuations influenced mass fluctuation between the following third and fourth days. These changes were usually compensatory, indicating that jays are able to regulate their body mass on a short-term basis, despite strong differences in their roles in reproduction. During reproduction, jays have a relatively predictable and abundant food supply, thus the appropriate strategy may be to maintain a stable body mass that balances some energy reserves against maintaining a low body mass for efficient flight, as required during reproduction.