Mining citizen science data to explore stopover sites and spatiotemporal variation in migration patterns of the red-footed falcon

Citizen science data have already been used to effectively address questions regarding migration, a fundamental stage in the life history of birds. In this study, we use data from eBird and from 3 additional regional citizen science databases to describe the migration routes and timing of the red-footed falcon Falco vespertinus in the Mediterranean region across 8 years (2010–2017). We further examine the seasonal and yearly variation in migration patterns and explore sites used during the species migration. Our results suggest that the autumn passage is spatially less variable and temporally more consistent among years than in spring and that birds migrate faster in spring than in autumn. The species seems to be more prevalent along the Central Mediterranean during spring migration, probably as a result of the clockwise loop migration that red-footed falcons perform. There was a high variation in annual median migration dates for both seasons as well as in migration routes across years and seasons. Higher variation was exhibited in the longitudinal component thus indicating flexibility in migration routes. In addition, our results showed the species’ preference for lowlands covered with cropland and mosaics of cropland and natural vegetation as stopover sites during migration. Stopover areas predicted from our distribution modeling highlight the importance of the Mediterranean islands as stopover sites for sea-crossing raptors, such as the red-footed falcon. This study is the first to provide a broad-scale spatiotemporal perspective on the species migration across seasons, years and flyways and demonstrates how citizen science data can inform future monitoring and conservation strategies.     

Movement patterns of the White-tailed Sea Eagle (Haliaeetus albicilla): post-fledging behaviour,natal dispersal onset and the role of the natal environment

Exploratory movements and natal dispersal form essential processes during early life history stages of raptors, but identifying the factors shaping individual movement decisions is challenging. Global positioning system (GPS) telemetry thereby provides a promising technique to study movement patterns on adequate spatio-temporal scales. We analysed data of juvenile White-tailed Sea Eagles Haliaeetus albicilla (WTSE) in north-east Germany (n = 24) derived from GPS tracking to extensively analyse movements between fledging and emigration from the natal territory. Our goal was to determine the time point of fledging, characterize pre-emigration movements and the onset of natal dispersal while investigating the influence of the natal environment. WTSE fledged at an average age of 72 days and showed strong excursive behaviour during the post-fledging period regarding the number, distance and duration of excursions, yet with high individual variability. Excursive behaviour did not differ between sexes. On average, WTSE left the parental territory 93 days after fledging. The quantity of excursive behaviour delayed the timing of emigration and WTSE tended to postpone their emigration when foraging water was accessible within the boundaries of their parental territory. The overall results suggest that young WTSE assess the quality of the natal environment via pre-emigration movements and stay in their territory of origin for as long as internal and external conditions allow for it. Our study is one of the first to characterize post-fledging and natal dispersal movements of young WTSE to such an extent and applies modern techniques to understand related movements in relation to the natal environment. The results emphasize the urgent necessity for the extension of currently existing nest protection periods and guaranteeing sustainable management of potential breeding and foraging grounds for WTSE. Ultimately, the results are relevant for all large raptor species sensitive to human-related disturbance, as they support the increasing importance of regulations with spatio-temporal specifications for breeding populations of large raptors in densely human-inhabited areas with increasing alteration of land.     

Do parents play a role in the timing and process of fledging by nestling Mountain Bluebirds?

What causes young birds to leave nests remains unclear for almost all altricial species. For many years, the assumption was that parents often controlled the time of fledging by coaxing young from nests, e.g., by holding food within view, but out of reach, of nestlings. This assumption, though, was based solely on scattered anecdotal reports of such behavior. We used continuous video‐recording of nests to assess the role of parents, if any, in the timing and process of fledging of cavity‐nesting Mountain Bluebirds (Sialis currucoides). We placed perches ~50 cm in front of nest‐box entrances to give parents ample opportunity to display food to nestlings. We found no evidence that parents routinely initiated the fledging process. On the day of fledging, parents did not perch on supplemental perches with food more often, or for longer periods of time, than on the day before fledging. Also, after going to nest‐box entrances, parents never held food away from a nestling reaching for the food. Parents were usually absent (16 of 19 cases) when the first nestling fledged. In the remaining three cases, a parent perched with food in view of a nestling for 8, 15 and 65 s, respectively, just before that nestling fledged. Although these might have appeared to be attempts at coaxing, in each case, the parent was encountering, for the first time, a nestling partially emerging from the nest entrance. Parents may simply have hesitated to approach nests because the nestling's position prevented parents from delivering food in the normal manner. Finally, the rate at which parents fed nestlings on the day of fledging did not differ from the rate the day before, suggesting that parents do not try to use hunger to induce fledging. Our results are consistent with previous research suggesting that, in Mountain Bluebirds, it is a nestling that initiates fledging, typically when it reaches some threshold state of development.     

The role of parent–offspring interactions during and after fledging in the Black-legged Kittiwake

Most bird species endure a high mortality at fledging, and selection should favour parental behaviour diminishing these costs. Post-fledging parental care varies greatly among species and is often linked to parent–offspring recognition. In the Black-legged Kittiwake (Rissa tridactyla), fledglings need to return to the natal nest to be fed by their parents until independence. Rejections of fledglings by non-parent adults may be fairly violent, and parents are expected to recognize and help their chicks at the time of first return. However, previous cross-fostering experiments pointed out that parents are not able to recognize their chicks up to 15 days before fledging. In this paper, we study the behaviour of both parents and juveniles at fledging. We found that parents answered significantly more to their fledgling's calls than to those of others. Compared to silent juveniles, juveniles that called before landing were more likely to be accepted by their parents. No such pattern was observed with foreign juveniles, indicating that fledglings’ voice may carry individual identity. Furthermore, fledglings found their way back to the natal nest faster when parents attended the natal nest and reacted to their offspring's calls than when they were absent or inactive. Such interactions may therefore diminish juvenile mortality at fledging.     

Heart rate increase and inappropriate sinus tachycardia after cryoballoon pulmonary vein isolation for atrial fibrillation

BackgroundCryoballoon pulmonary vein isolation (PVI) is a common therapy for atrial fibrillation (AF). While moderately increased sinus rhythm heart rate (HR) after PVI has been observed, inappropriate sinus tachycardia (IST) is a rare phenomenon. We aimed to investigate the prevalence and natural history of an abnormal sinus HR response after cryoballoon PVI.MethodsWe included 169/646 (26.2%) patients with AF undergoing PVI with available Holter recordings before and 3, 6 and 12 months after the procedure. Patients with AF on Holter monitoring were excluded. Mean HR increase ≥ 20 bpm or an IST-like pattern (mean HR > 90 bpm or > 80 bpm when beta-blocking agents were used) following PVI was categorised as abnormal sinus HR response.ResultsFollowing PVI, mean HR ± standard deviation increased in the entire group from 63.5 ± 8.4 to 69.1 ± 9.9 bpm at 3 months (p < 0.001), and to 71.9 ± 9.4 bpm at 6 months (p < 0.001). At 12 months, mean HR was 71.2 ± 10.1 bpm (p < 0.001). Only 7/169 patients (4.1%) met criteria for abnormal sinus HR response: mean HR was 61.9 ± 10.6 bpm (pre-ablation), 84.6 ± 9.8 bpm (3 months), 80.1 ± 6.5 bpm (6 months) and 76.3 ± 10.1 bpm (12 months). Even at 12 months, mean HR was significantly different from that pre-ablation in this group (p = 0.033). However, in patients meeting IST-like pattern criteria, mean HR at 12 months was no longer significantly different from that pre-ablation.ConclusionFew patients had an abnormal sinus HR response after PVI. Peak HR was observed 3 months after PVI, but HR was still significantly increased 12 months post-ablation compared with pre-ablation. An IST-like pattern was rarely observed. In these patients, HR decreased to pre-ablation values within a year.     

Inter-Annual Variability of Fledgling Sex Ratio in King Penguins

As the number of breeding pairs depends on the adult sex ratio in a monogamous species with biparental care, investigating sex-ratio variability in natural populations is essential to understand population dynamics. Using 10 years of data (2000–2009) in a seasonally monogamous seabird, the king penguin (Aptenodytes patagonicus), we investigated the annual sex ratio at fledging, and the potential environmental causes for its variation. Over more than 4000 birds, the annual sex ratio at fledging was highly variable (ranging from 44.4% to 58.3% of males), and on average slightly biased towards males (51.6%). Yearly variation in sex-ratio bias was neither related to density within the colony, nor to global or local oceanographic conditions known to affect both the productivity and accessibility of penguin foraging areas. However, rising sea surface temperature coincided with an increase in fledging sex-ratio variability. Fledging sex ratio was also correlated with difference in body condition between male and female fledglings. When more males were produced in a given year, their body condition was higher (and reciprocally), suggesting that parents might adopt a sex-biased allocation strategy depending on yearly environmental conditions and/or that the effect of environmental parameters on chick condition and survival may be sex-dependent. The initial bias in sex ratio observed at the juvenile stage tended to return to 1∶1 equilibrium upon first breeding attempts, as would be expected from Fisher’s classic theory of offspring sex-ratio variation.     

THE SELECTION OF TITS PARUS SPP. BY SPARROWHAWKS ACCIPITER NISUS

Selection of the Wytham Wood population of tits by Sparrowhawks during the tit post-fledging period was studied over three years. Within three weeks of the median date of tit fledging, juvenile Blue Tits were selected more frequently than juvenile Great Tits but thereafter juvenile Great Tits were selected more frequently; it is suggested that the former was due to greater vulnerability of Blue Tits in the two to three weeks after fledging, and the latter due to changes in availability due to immigration/emigration of juvenile tits. When juvenile tits killed by hawks were compared on the basis of brood and physical characteristics with their cohorts in the entire population and in those surviving to the following year, only one factor, fledging date, was found to have affected selection by hawks. It is believed that this was because hawks selected late fledged young still in family parties in preference to early fledged young which had already become independent of their parents and were foraging in the better cover of the forest canopy. When adults killed by hawks were compared with all adults available for selection on the basis of species, sex, timing of nesting and whether or not they had been born in the wood, the only selection trend found was that male Great Tits were taken more often than females due, possibly, to greater risk of exposure for males while foraging or during territorial behaviour. When compared with availability, juveniles were selected more frequently than adults in only one year, possibly a result of yearly differences in the number of prey available per hawk, the rate of non-predator related juvenile mortality or unknown hawk hunting strategies. The overall finding of relative non-selectivity by hawks was attributed to the surprise factor associated with the hunting methods used by Sparrowhawks in woodland.     

Cooperative breeding shapes post‐fledging survival in an Afrotropical forest bird

For avian group living to be evolutionary stable, multiple fitness benefits are expected. Yet, the difficulty of tracking fledglings, and thus estimating their survival rates, limits our knowledge on how such benefits may manifest postfledging. We radio‐tagged breeding females of the Afrotropical cooperatively breeding Placid greenbul (Phyllastrephus placidus) during nesting. Tracking these females after fledging permitted us to locate juvenile birds, their parents, and any helpers present and to build individual fledgling resighting datasets without incurring mortality costs or causing premature fledging due to handling or transmitter effects. A Bayesian framework was used to infer age‐specific mortality rates in relation to group size, fledging date, maternal condition, and nestling condition. Postfledging survival was positively related to group size, with fledglings raised in groups with four helpers showing nearly 30% higher survival until independence compared with pair‐only offspring, independent of fledging date, maternal condition or nestling condition. Our results demonstrate the importance of studying the early dependency period just after fledging when assessing presumed benefits of cooperative breeding. While studying small, mobile organisms after they leave the nest remains highly challenging, we argue that the telemetric approach proposed here may be a broadly applicable method to obtain unbiased estimates of postfledging survival.     

Brood division and transition to independence in Blackbirds Turdus merula

Blackbirds Turdus merula rearing young in the Botanic Garden, Oxford, were observed over three summers (1979–81). Between 0 and 10 days after fledging the young were divided between the parents so that each fed only certain fledglings and refused to feed others. This division was temporally stable. In broods where another nesting attempt followed, the male usually took responsibility for all the young, but in final broods they were divided fairly evenly. The probability of a fledgling surviving to independence declined as the number of young a parent fed increased; thus division should be favoured. However, if the female fed some young the inter-nest interval increased and the potential number of young that could be raised in that season was curtailed. This trade-off is examined by means of a model. After fledging the young improved in their ability to capture prey successfully and increased the size of the prey taken. At 15–24 days after fledging, self-feeding became more profitable than parental feeding and the young became fully independent. The timing of this transition is influenced by the parents, and it is suggested that by dividing the brood, parental feeding can be more carefully regulated so that finer control over the timing of independence is achieved.     

Protective effect of aldehyde dehydrogenase 2 against rat corneal dysfunction caused by streptozotocin-induced type I diabetes

Aldehyde dehydrogenase 2 plays a pivotal role in detoxifying aldehydes, and our previous study revealed that aldehyde dehydrogenase 2 could alleviate diabetic retinopathy-associated damage. We aimed to characterize the potential role of aldehyde dehydrogenase 2 in diabetic keratopathy. Twenty-four rats with streptozotocin-induced (60 mg/kg, single intraperitoneal injection) type 1 diabetes mellitus (T1DM) were divided the T1DM group and the T1DM + Alda1 (an activator of aldehyde dehydrogenase 2) group (5 mg/kg/d, intraperitoneal injection, 1/2/3 months), while an additional 12 healthy rats served as the control group. Corneal morphology was examined in vivo and in vitro at one, two, and three months after T1DM induction. Additionally, serum inflammatory factors were measured by ELISA, and the expression of corneal vascular endothelial growth factor A (VEGF-A) and aldehyde dehydrogenase 2 was measured by immunofluorescence staining. Corneal cell death was evaluated by terminal-deoxynucleotidyl transferase-mediated nick end labeling (TUNEL) staining. Slit lamp analysis showed that the area of corneal epithelial cell injury in the T1DM + Alda1 group was significantly smaller than that in the T1DM group at one and two months after T1DM induction (all P < 0.05). OCT analysis and HE staining showed that the central corneal thickness (indication of corneal edema) and the epithelial keratinization level in the T1DM + Alda1 group was evidently decreased compared with those in the T1DM group (all P < 0.05). The serum inflammatory factors interleukin-1 and interleukin-6 were significantly upregulated in the T1DM group compared with the T1DM + Alda1 group at three months after T1DM induction (all P < 0.05), while there were no differences in SOD or TNF-α levels among all groups. Furthermore, corneal VEGF-A expression and corneal cell death in the T1DM + Alda1 group were dramatically reduced compared to those in the T1DM group (all P < 0.05). In conclusion, the aldehyde dehydrogenase 2 agonist Alda1 attenuated rat corneal dysfunction induced by T1DM by alleviating corneal edema, decreasing corneal cell death, and downregulating corneal VEGF-A expression.     

Post‐fledging survival of Little Owls Athene noctua in relation to nestling food supply

Among the range of determinants of post‐fledging survival in altricial birds, the energy supply to the growing juveniles is likely to play a central role. However, the exact mechanisms shaping post‐fledging survival are poorly understood. Using a food supplementation experiment, we determined the effect of variation in food supply on the survival of juvenile Little Owls Athene noctua from hatching to 2 months post‐fledging. Experimental broods were food‐supplemented for 36 days during the nestling and the early post‐fledging period. The fate of 307 juveniles (95 of them provided with extra food) was determined by nest monitoring and radiotelemetry. In unsupplemented birds, the rates of survival measured at 5‐day intervals were lowest during the nestling stage, remained low during the early post‐fledging stage and steadily increased after about 2 weeks post‐fledging. Food supplementation substantially increased nestling survival, but we detected no direct treatment effect on post‐fledging survival. Instead, we found a strong indirect effect of food supplementation, in that fledglings of good physical condition had markedly higher chances of surviving the post‐fledging period compared with those in poor condition. Experimental food supplementation increased survival over the first 3 months from 45% to 64.6%. This suggests that energy reserves built up during the nestling stage influence post‐fledging survival and ultimately parental reproductive output. The low nestling and post‐fledging survival shows that the early life‐history stages constitute a crucial bottleneck of reproductive ecology in Little Owls. The strong treatment effects on the number of independent offspring indicate that natural variation in food supply is an important determinant of spatio‐temporal patterns in Little Owl demography.     

Bone mass and quality in patients with juvenile idiopathic arthritis: longitudinal evaluation of bone-mass determinants by using dual-energy x-ray absorptiometry,peripheral quantitative computed tomography,and quantitative ultrasonography

Introduction

Our objective was to evaluate longitudinally the main bone-mass and quality predictors in young juvenile idiopathic arthritis (JIA) patients by using lumbar spine dual-energy X-ray absorptiometry (DXA) scan, radius peripheral quantitative computed tomography (pQCT), and phalangeal quantitative ultrasonography (QUS) at the same time.

Methods

In total, 245 patients (172 females, 73 males; median age, 15.6 years: 148 oligoarticular, 55 polyarticular, 20 systemic, and 22 enthesitis-related-arthritis (ERA) onset) entered the study. Of these, 166 patients were evaluated longitudinally. Data were compared with two age- and sex-matched control groups.

Results

In comparison with controls, JIA patients, but not with ERA, had a reduced spine bone-mineral apparent density (BMAD) standard deviation score (P < 0.001) and musculoskeletal deficits, with significantly lower levels of trabecular bone mineral density (TrabBMD) (P < 0.0001), muscle cross-sectional area (CSA) (P < 0.005), and density-weighted polar section modulus (SSIp) (P < 0.05). In contrast, JIA showed fat CSA significantly higher than controls (P < 0.0001). Finally, JIA patients had a significant reduced amplitude-dependent speed of sound (AD-SoS) (P < 0.001), and QUS z score (P < 0.005).Longitudinally, we did not find any difference in all JIA patients in comparison with baseline, except for the SSIp value that normalized. Analyzing the treatments, a significant negative correlation among spine BMAD values, TrabBMD, AD-SoS, and systemic and/or intraarticular corticosteroids, and a positive correlation among TNF-α-blocking agents and spine BMAD, TrabBMD, and AD-SoS were observed.

Conclusions

JIA patients have a low bone mass that, after a first increase due to the therapy, does not reach the normal condition over time. The pronounced bone deficits in JIA are greater than would be expected because of reduction in muscle cross-sectional area. Thus, bone alterations in JIA likely represent a mixed defect of bone accrual and lower muscle forces.     

Maxent modeling for predicting the spatial distribution of three raptors in the Sanjiangyuan National Park,China

Upland buzzard (Buteo hemilasius), Saker falcon (Falco cherrug), and Himalayan vulture (Gyps himalayensis) are three common large raptors in the Sanjiangyuan National Park (SNP), China's first national park. Among them, Upland buzzard and Saker falcon play a significant role in controlling plateau rodent populations and reducing the transmission of pathogens carried by rodents. The Himalayan vulture can provide services for the redistribution and recycling of nutrients in the ecosystem, and play an irreplaceable role in the celestial burial culture of Tibetans in China. Exploring their habitat suitability is important for the protection of the three raptors. Our research was based on the current distribution of Upland buzzard, Saker falcon, and Himalayan vulture that we had extensively surveyed in the Sanjiangyuan National Park from 2016 to 2017. Combined with the correlation analysis of environmental variables, we utilized maximum entropy model (MaxEnt) to evaluate and compare the habitat suitability of the three species in the Sanjiangyuan National Park. Elevation, climate, and human disturbance factors, which had direct or indirect effects on species survival and reproduction, were all included in the model. Among them, elevation was the most important environmental variables affecting the suitability of habitats of three species. Temperature‐related factor was another important predictor. The high (>60%) suitable habitat areas for Upland buzzard, Saker falcon, and Himalayan vulture were 73,017.63, 40,732.78, and 61,654.33 km², respectively, accounted for 59.32%, 33.09%, and 50.08% of the Sanjiangyuan National Park and their total suitable area (i.e., the sum area of high and moderate habitats) reached 96.07%, 60.59%, and 93.70%, respectively. Besides, the three species have overlapping areas for the suitable habitats, which means that overlapping areas should be highly valued and protected. Therefore, understanding the distribution of suitable habitats of the three raptors can provide useful information and reasonable reference for us to put forward suggestions for their protection and regional management.     

Stabilizing selection on blue tit fledgling mass in the presence of sparrowhawks

Like British great tits, Belgian blue tits have a lower winter body mass when sparrowhawks are present. Since body mass affects manoeuvrability in small birds, tits may balance the risks of starvation and the risk of hawk predation by varying the amount of extra fat carried during winter. Predation pressure by sparrowhawks on young and inexperienced fledglings is at least as intense as that on the adults during winter. We therefore expected that tit fledgling body mass could also be reduced in the presence of sparrowhawks. In the years after one pair of sparrowhawks settled in a study plot, the mean body mass of blue tit fledglings was lower compared with that in years when there were no sparrowhawks. Furthermore, the shape of the curve relating juvenile survival to fledging mass changed, because the survival of the heaviest fledglings was reduced, which altered the selection differential of juvenile survival as a function of body mass from directional to stabilizing. Of seven published studies on the fledgling body mass–survival relation in tits, all three of the studies conducted in the absence of sparrowhawks showed the highest survival rates for the heaviest young, whereas in all four studies with sparrowhawks present this was no longer the case.     

Comparison of remission criteria in a tumour necrosis factor inhibitor treated rheumatoid arthritis longitudinal cohort: patient global health is a confounder

Introduction

Our objectives were to assess the frequency and sustainability of American College of Rheumatology (ACR)/European League against Rheumatism (EULAR) and Disease Activity Score (DAS)28(4v)–C-reactive protein (CRP) remission 12 months after the initiation of tumour necrosis factor inhibitor (TNFi) therapy in a rheumatoid arthritis (RA) cohort.

Methods

Data were collected of 273 biologic naive RA patients at baseline, then 3, 6 and 12 months post-TNFi therapy. Remission status was calculated using DAS28(4v)-CRP <2.6 and ACR/EULAR Boolean criteria. Response was scored using EULAR criteria.

Results

Mean (range) patient age was 59.9 (7.2-85.4) years with disease duration of 13.4 (1.0-52.0) years. Responder status maintained from 3–12 months (86%, 82.4%), laboratory/clinical parameters (erythrocyte sedimentation rate (ESR), CRP, patient global health (PGH), DAS28(4v)-CRP) also showed sustained improvement (P < 0.05). DAS28 remission was reached by 102 subjects at 1 year, 27 patients were in Boolean remission, but 75 missed it from the DAS28 remission group. Patients in remission were younger (P = 0.041) with lower baseline tender joint count (TJC)28 and PGH than those not in remission (P = 0.001, P = 0.047). DAS28 remission patients were older (P = 0.026) with higher 12 months PGH and subsequently higher DAS28 than Boolean remission patients (P < 0.0001). Patients not achieving Boolean remission due to missing one subcriteria most frequently missed PGH ≤1 criteria (79.8%).

Conclusions

Only 10% of this TNFi treated cohort achieved remission according to the new ACR/EULAR criteria, which requires lower disease activity. More stringent criteria may ensure further resolution of disease activity and better longterm radiographic outcome, which supports earlier intervention with biologic therapy in RA.     

Sex,growth rate,rank order after brood reduction,and hatching date affect first‐year survival of long‐lived Herring Gulls

Among most species of birds, survival from hatching throughout the first year of life is generally lower than subsequent survival rates. Survival of young birds during their first year may depend on a combination of selection, learning, unpredictable resources, and environmental events (i.e., post‐fledging factors). However, knowledge about post‐fledging development in long‐lived species is usually limited due to a lengthy immature stage when individuals are generally unobservable. Therefore, pre‐fledging characteristics are often used to predict the survival of young birds. We assessed effects of nestling growth rates, hatching date, hatching asynchrony, brood size and rank order after brood reduction, and sex on first‐year survival of 137 fledglings using a mark‐resighting analysis. We found that the survival probability (Φ_1yr = 0.39) of first‐year Herring Gulls (Larus argentatus) in our study colony located at the outer port of Zeebrugge (Belgium) was lower than that of older individuals (Φ_>1yr = 0.75). All 10 models best supported by our data included nestling growth rate, suggesting that variability in first‐year survival may be linked primarily to individual variation in growth. First‐year survival was negatively correlated with hatching date and rank order after brood reduction. Hence, carry‐over effects of breeding season events such as timing of breeding, early development, and social status had an influence on survival of Herring Gulls after fledging. Furthermore, we found sex‐biased mortality in first‐year Herring Gulls, with females (Φ_1yr = 0.45) surviving better than males (Φ_1yr = 0.38). Although adult survival is generally regarded as the key parameter driving population trajectories in long‐lived species, juvenile survival has recently been acknowledged as an important source of variability in population growth rates. Thus, increasing our knowledge of factors affecting age‐specific survival rates is necessary to improve our understanding of population dynamics and ultimately life‐history variation.     

Follistatin Protein Enhances Satellite Cell Counts in Reinnervated Muscle

Background Muscle recovery following peripheral nerve repair is sup-optimal. Follistatin (FST), a potent muscle stimulant, enhances muscle size and satellite cell counts following reinnervation when administered as recombinant FST DNA via viral vectors. Local administration of recombinant FST protein, if effective, would be more clinically translatable but has yet to be investigated following muscle reinnervation. Objective  The aim of this study is to assess the effect of direct delivery of recombinant FST protein on muscle recovery following muscle reinnervation. Materials and Methods  In total, 72 Sprague-Dawley rats underwent temporary (3 or 6 months) denervation or sham denervation. After reinnervation, rats received FST protein (isoform FS-288) or sham treatment via a subcutaneous osmotic pump delivery system. Outcome measures included muscle force, muscle histomorphology, and FST protein quantification. Results  Follistatin treatment resulted in smaller muscles after 3 months denervation ( p  = 0.019) and reduced force after 3 months sham denervation ( p  < 0.001). Conversely, after 6 months of denervation, FST treatment trended toward increased force output ( p  = 0.066). Follistatin increased satellite cell counts after denervation ( p  < 0.001) but reduced satellite cell counts after sham denervation ( p  = 0.037). Conclusion  Follistatin had mixed effects on muscle weight and force. Direct FST protein delivery enhanced satellite cell counts following reinnervation. The positive effect on the satellite cell population is intriguing and warrants further investigation.     

Postfledging Survival and Development of Juvenile Lilac-Crowned Parrots

Abstract: We fitted radiotransmitters to 68 lilac-crowned parrot (Amazona finschi) fledglings from 1996 to 2003 to determine the survival and development of juveniles during their first year after leaving the nest. Overall, first-year survival was 73% (CI = 53–94%) and all mortalities occurred within 5 weeks of fledging, with highest mortality in the first week postfledging. Survival varied between years, influencing recruitment of independent young in the population. Nesting lilac-crowned parrots produced 0.70 independent young per egg-laying pair during 1996–2003. Lowest productivity of 0.25 independent young per pair occurred in 2003, with 40% postfledging survival. Juvenile development after fledging was characterized by variations in mobility, distance from the nest, and separation distance between siblings. Mobility and distance of young birds from the nest increased linearly with months postfledging. The first 2–3 weeks after fledging were characterized by low mobility and survival of young parrots, making this the most critical phase postfledging. The dependency period for young parrots extended to 4–5 months postfledging and was characterized by increased mobility and low separation between siblings, as juveniles traveled in family groups. Independence occurred in month 5 and was marked by a significant increase in mobility and separation between siblings, indicating the break-up of family groups. The first weeks after leaving the nest were crucial for survival and highlight the need for secure habitats where fledglings can improve flight and locomotory skills. The 4–5-month dependency of young parrots may be a key period for development, enhancing survival, and establishment in the breeding population. Release programs need to replicate learning and development acquired during the postfledging dependency phase to enhance survival of captive-reared psittacines. Researchers should conduct surveys of parrot group sizes during the dependency period 1–4 months after the end of nesting to provide reliable demographic data on annual recruitment of wild populations.     

Covariation between bill colouration and fitness components in a nocturnal bird

Vividly coloured chromatic signals play a key role in social and sexual signalling in diurnal birds, but their role is considered negligible in favour of achromatic (i.e. white, pure grey and black colourations) signals in nocturnal species. Here we studied colour variation and potential signalling of the yellow bill – a trait functioning as sexual signal in diurnal raptors during the breeding season in females of a truly nocturnal raptor, the little owl Athene noctua. We found that yellow‐red chroma of the bill was highly variable between individuals and positively correlated with female fitness prospects (i.e. brood size at fledging). In addition, we found that females with brighter bills were larger in size and produced owlets with a higher mass at fledging. This study suggests that yellow bill colouration in female little owls may potentially play a role in sexual signalling and may constitute the first evidence of chromatic colour signalling in a nocturnal bird.     

The contribution of flight capability to the post‐fledging dependence period of golden eagles

The period prior to an individual emigrating from its natal site and initiating dispersal is important for developing the skills that are ultimately required for surviving natal dispersal. Using a novel method to quantify the early movements of 35 juvenile golden eagles fitted with satellite transmitters, we hypothesised that variation in golden eagles’ post‐fledging dependence period (PFDP) was determined by variation in how quickly movement skills were acquired in order to become independent and disperse. Twenty nine young eagles exhibited an initial increase in mobility (‘ontogenic phase’) levelling off after a median of 68 d, followed by a period of maintained mobility (‘maintained phase’) that lasted a median of 99 d (range 24–176). Eagles that developed their mobility more quickly during the ontogenic phase had a correspondingly shorter ontogenic phase. Despite this, most of the inter‐individual variation in the length of the PFDP resulted from variation in the length of the ‘maintained phase’. In general, females (the larger sex) developed more slowly and had a longer ontogenic phase. Males exhibited dispersal strategies around two modes with some dispersing early (mode 1: 89.5 d) and others late (mode 2: 220 d). In contrast females dispersed around a unimodal distribution of timing (mode 167.5 d). Apart from six individuals (mostly males) which dispersed with no discernible maintained phase, most offspring remained in the parental home range after they were fully mobile, even those that developed mobility quickly, suggesting that the PFDP in golden eagles is not simply a function of physical capacity for independence, but also a period when young eagles decide to remain, and are tolerated by parents, in their parental home range before dispersing. We suggest that delaying dispersal may be a beneficial strategy for young raptors facing a competitive environment after PFDP.