Bill Length Research Articles

Machine Learning Predictive Models Analysis on Telecommunications Service Churn Rate

Customer churn frequently occurs in the telecommunications industry, which provides services and can be detrimental to companies. A predictive model can be useful in determining and analyzing the causes of churn actions taken by customers. This paper aims to analyze and implement machine learning models to predict churn actions using Kaggle data on customer churn. The models considered for this research include the XG Boost Classifier algorithm, Bernoulli Naïve Bayes, and Decision Tree algorithms. The research covers the steps of data preparation, cleaning, and transformation, exploratory data analysis (EDA), prediction model design, and analysis of accuracy, F1 Score, receiver operating characteristic (ROC) curve, and area under the ROC curve (AUC) score. The EDA results indicate that the contract type, length of tenure, monthly invoice, and total bill are the most influential features affecting churn actions. Among the models considered, the XG Boost Classifier algorithm achieved the highest accuracy and F1 score of 81.59% and 74.76%, respectively. However, in terms of efficiency, the Bernoulli Naïve Bayes and Decision Tree algorithms outperformed XG Boost, with AUC scores of 0.7469 and 0.7468, respectively.

Morphology and niche evolution influence hummingbird speciation rates.

How traits affect speciation is a long-standing question in evolution. We investigate whether speciation rates are affected by the traits themselves or by the rates of their evolution, in hummingbirds, a clade with great variation in speciation rates, morphology and ecological niches. Further, we test two opposing hypotheses, postulating that speciation rates are promoted by trait conservatism or, alternatively, by trait divergence. To address these questions, we analyse morphological (body mass and bill length) and niche traits (temperature and precipitation position and breadth, and mid-elevation), using a variety of methods to estimate speciation rates and correlate them with traits and their evolutionary rates. When it comes to the traits, we find faster speciation in smaller hummingbirds with shorter bills, living at higher elevations and experiencing greater temperature ranges. As for the trait evolutionary rates, we find that speciation increases with rates of divergence in the niche traits, but not in the morphological traits. Together, these results reveal the interplay of mechanisms through which different traits and their evolutionary rates (conservatism or divergence) influence the origination of hummingbird diversity.

Female-dependent factors affect sex allocation in Lesser Kestrels Falco naumanni

Abstract The sex ratio of nestlings is a crucial population determinant in rare and/or endangered species. We investigated the role of female body condition and female-related traits in Lesser Kestrel (Falco naumanni) nestling sex allocation at a nest-box colony in central Greece. We used the total clutch volume and size, female weight, hatching dates, body length, wing length, tail length, tarsometatarsus, and bill length as explanatory variables of the number of male nestlings (the response variable) using CART model analysis. This analysis showed that the reproduction output was biased towards male nestlings when female parents were shorter in body length and clutch size and volume were smaller. The skewed sex ratio favoring females, 1:2.35, suggests that when female parents are in good condition, they invest most in good-quality female nestlings, providing a reproductive advantage and increased long-term fitness.

Long-term decline in fledging body condition of Flesh-footed Shearwaters (Ardenna carneipes)

Abstract Marine systems are under increasing pressure from anthropogenic activities. In recent decades, the deteriorating condition of the world’s seabird populations suggests these pressures have reached a tipping point. For young birds, body mass can significantly influence survival in the critical period between nest departure and recruitment to the breeding population. On Lord Howe Island, we measured Flesh-footed Shearwater (Ardenna carneipes) fledglings in the colony and adjacent beaches to determine how body condition changed during 2010–2022. Overall, we found chick body mass as well as wing, culmen, and head + bill length declined over time with larger declines observed in beach-washed birds. Culmen and head + bill length declined by 0.17 and 0.23 mm/year, respectively, and body mass by 16.1 g/year. The number of chicks fledging at <400 g has increased sharply in recent years, meaning significant numbers of birds are unlikely to survive after departing the island. Our results point to a deepening of the division in the shearwater population: adult birds who can successfully provision sufficient nutrient reserves so their chick fledges successfully, and those who cannot. In this latter group, failure at the fledging stage (beached birds) is resulting in birds in increasingly poor condition, the likes of which were seldom documented 13 years ago.

Morphological Covariance and Onset of Foot Prehensility as Indicators of Integrated Evolutionary Dynamics in the Herons (Ardeidae).

The ultimate form an organism attains is based, in part, on the rate and timing of developmental trajectories and on compensatory relationships between morphological traits. For example, there is often an inverse correlation between the relative size of an organism's head and the length of its legs. Avian examples with a disproportionately small head and long legs include ostriches (Struthionidae), flamingos (Phoenicopteridae), cranes (Gruidae), and stilts (Recurvirostridae). To determine whether a possible compensatory relationship exists between relative head size and hind-limb length in a typically long-legged family of birds-the Ardeidae-we measured and analyzed skull dimensions (length, width, and height of cranium, and bill length) and skeletal hind-limb dimensions (femur, tibiotarsus, and tarsometatarsus) of the 12 North American species (north of Mexico) and of 12 additional taxa, including the morphologically divergent Agamia and Cochlearius. We found that Ardea species exhibit the smallest relative head sizes associated with the longest legs, while Butorides, Nycticorax, Nyctanassa, and Cochlearius have among the largest heads relative to hind-limb length. Furthermore, both positive and negative allometries occur in paired comparisons between the three hind-limb bones, expressed in tall morphotypes having disproportionately short femurs while short-legged morphotypes exhibit disproportionately long femurs; we show that this relationship has implications for foraging behavior. Moreover, the nestlings of short-legged herons exhibit functional precociality of the hind limbs through an early onset of prehensile ability of the feet to grasp branches, which is later expressed in adult foraging mode. This developmentally accelerated prehensile function in small-bodied species may be attributed, in part, to selection for predator avoidance in the early nestling stage.

Aviary measurements of dominance and affiliation between members of mixed-species birds flocks in southern China

In mutualistic interactions, all parties are usually considered to benefit; yet there may be asymmetries in mutualisms where some partners/individuals benefit more than others. Such is thought to be the case in mixed-species flocks of birds, where following species are thought to benefit more than leading species, and leading species may not be able to escape the association if they are subordinate to other species. We measured dominance and affiliation patterns of a mixed-species flock system of southern China in an aviary where these variables could be measured in a standardized way. In eight wild-caught flocks, the leading species, David's Fulvetta (Alcippe davidi), was usually among the more subordinate flock members (ranking 9 of 13 species, with the the most dominant species ranked number one, and dominance measured by normalized David's scores). Dominance was strongly influenced by body mass, and not by bill length or the number of individuals. Female fulvettas in particular tended to be among the most subordinate individuals in the flock. There was evidence of a negative relationship between a species pair's affiliation, measured as the percentage of all observations in which these two species were found perching together, and their difference in ranking in the dominance hierarchy, particularly when some ground species, which are not likely to remain in flocks long term, were removed from the analysis. Species pairs that had more pronounced differences in their dominance rankings were less likely to be affiliated, which is consistent with the idea that subordinate species may avoid dominants. David's Fulvetta is a strong information provider, so other species are likely benefitted in this relationship. Our data suggest one reason that fulvettas stay in flocks is that they may be subordinate and therefore have little control over who associates with them.

Consumption of arthropods by hummingbirds in the Sierra Madre de Chiapas, Mexico

An organism's morphological features can determine the type of prey they consume due to adaptive advantages in capturing them, for example, the shape and length of the bill in birds. Hummingbirds have been considered specialists in nectar consumption. However, they have been documented to also be important insectivores in ecosystems. In this study, we evaluated arthropod consumption by hummingbirds in relation to their bill and capture strategies. We theorized that hummingbirds with short-medium bills (9-11 bill length to body mass cube root ratio) capture a higher proportion of non-flying arthropods, as they have a lower linear speed of closure of the bill tip relative to the base, while species with long bills (13-14) capture mainly flying arthropods. The study was conducted in El Triunfo Biosphere Reserve, Chiapas, southeastern Mexico from 2015 to 2016, where seven hummingbird species that captured arthropods, their strategies of capture, and the type of prey consumed were recorded. We also analyzed the stomach contents (n = 72 stomachs) collected in the Sierra Madre de Chiapas. We calculated the frequency of occurrence of arthropods and their diversity, as well as the breadth of the feeding niche and the bill-prey relationship of 15 hummingbird species. The Green-throated Mountain-gem ( Lampornis viridipallens) and Rivoli's Hummingbird ( Eugenes fulgens) presented the highest richness of arthropod consumption. Arthropod prey belonged to eight orders, where Hymenoptera and Diptera were the most frequent. The most recorded capture strategies were on the substrate in sustained flight (37.5%) and hovering in sustained flight (33.3%). A positive association was found between the type of arthropods consumed and the morphological traits of the hummingbirds, non-flying arthropods were captured by hummingbirds with short-medium bills, while hummingbirds with long bills captured flying arthropods. Morphological adaptations for food resource use are a trait that determines food selection, capture, and handling success.

물까치(Cyanopica cyanus)의 형태학적 측정에 의한 성 판별

Most sexually monomorphic species, including the family Corvidae, are visually indistinguishing in field investigations. We investigated intersexaul morphological differences of the Azure-winged magpie (Cyanopica cyanus). We caught 86 adults (67 males, 14 females, and 5 unidentified), measured their morphological characteristics (head-bill length, bill length, maximum and minimum wing length, tarsus length, body length, tail length, and weight), and collected blood samples. Sex was determined by PCR amplification using the previously used P2/P8 (Griffiths et al. 1998) primers. Statistical analysis was used to compare morphological differences between sexes. Males were longer in body length and maximum wing length, and discriminant function analysis using the two variables showed the sex was distinguished with an accuracy of 71.7%. We discussed the significance of the two variables in the monomorphic Azure-winged magpies.

Test of Ecogeographical Rules on Sparrows (Passer spp.) along the Elevation Gradient of the Himalaya in Central Nepal

Animals inhabiting colder climates have a larger body size (Bergmann’s rule) and smaller body extremities (Allen’s rule), which help homeothermic animals to retain heat. Such ecogeographical phenomena have frequently been observed in animals along the latitudinal gradient and have occasionally been tested along the elevational gradient. This study tested whether these ecogeographic rules hold true for the morphology of sparrows (Passer spp.) along the elevational gradient offered by the Himalaya in central Nepal. Seventy house sparrows and twenty-eight tree sparrows were captured from 22 different localities of central Nepal between 100 and 3400 m asl, and morphological traits such as body size (body mass, tarsus length, wing length and tail length) and body extremities (bill length and bill width) were measured. Linear regression analysis was used to test the association of morphological measurements with elevation and climatic variables. House sparrows (Passer domesticus) had a wider elevational distribution range and exhibited significantly larger body sizes than the Eurasian tree sparrows (P. montanus). House sparrows had larger body sizes and smaller bills at higher elevations in adherence to Bergmann’s rule and Allen’s rule. Bill length in house sparrows showed a positive association with the temperature following the proposition of Allen’s rule. However, the morphological measurements in Eurasian tree sparrows did not show a distinct pattern with elevation and climatic variables. Therefore, this study concludes that ecogeographical phenomena such as Bergmann’s rule and Allen’s rule could be species-specific based on their biological and ecological characteristics.

Importance of species traits on individual-based seed dispersal networks and dispersal distance for endangered trees in a fragmented forest.

Although mutualistic network analyses have sparked a renewed interest in the patterns and drivers of network structures within communities, few studies have explored structural patterns within populations. In an endangered tree species population, plant individuals share their bird seed dispersers; however, the factors affecting individual interaction patterns are poorly understood. In this study, four individual-based networks were built for the endangered Chinese yew, Taxus chinensis, in a fragmented forest based on bird foraging type (swallowing and pecking networks) and habitat type (networks in a bamboo patch and an evergreen broad-leaved forest patch). Species-level network metrics (species degree and specialization, d’) were used to evaluate the effects of species traits (bird and plant traits) on species-level networks and dispersal distance for T. chinensis. It was revealed that the interaction networks between T. chinensis individuals and their bird partners were influenced by foraging type and the habitat of plant distribution. Compared to the other two networks, bird swallowing and bird–fruit networks in the evergreen broad-leaved patch habitat had higher nestedness and connectance but lower modules and specialization. Bird (body weight and wing and bill lengths) and plant traits (height, crop size, and cover) significantly affected species-level network metrics such as degree and specialization. Furthermore, seed dispersal distance was influenced by species traits and the species-level metrics of fruit–bird interaction networks. These results provide new insights into individual-based seed dispersal mutualistic networks of endangered plant species under habitat fragmentation. Moreover, these findings have relevant implications for conserving and managing individual endangered trees in increasingly disturbed ecosystems.

Morphometric measurements, productive and reproductive performance of Deshi black and Deshi white duck

At the Central Duck Breeding Farm Hajiganj in Narayanganj, Bangladesh, morphometrics, productive, and reproductive performances of Deshi black and Deshi white ducks were measured under intensive conditions. Body length, head length, bill length, neck length, feather length, and shank length of mature male and female Deshi black and Deshi white ducks measured 59.56 ± 0.87 cm and 61.87 ± 0.48 cm, 2.25 ± 0.12 cm, and 3.4 ± 0.06 cm, 5.86 ± 0.12 cm, and 6.23 ± 0.06 cm, 19.21 ± 0.47 cm and 21.08 ± 0.26 cm, 21.85 ± 0.53 cm and 26.71 ± 0.29 cm, 9.93 ± 0.29 cm and 10.81 ± 0.16 cm, respectively. Morphometric features were significantly (p < 0.01, p < 0.05) higher in females than males. But no significant differences (p > 0.05) were detected between the two types of ducks except for the body, head, and feather length (p < 0.01, p < 0.05). At a day old, 4th week, 8th week, and 12th week of age, the body weights (LSMean ± SE) of male and female Deshi black and Deshi white ducks were 42.65 ± 0.35 gm and 43.40 ± 0.35 gm, 318.00 ± 9.13 gm and 319.04 ± 9.13 gm, 835.85 ± 8.94 gm and 794.20 ± 8.94 gm, 1345.80 ± 2.67 gm and 1347.90 ± 2.67 gm, respectively (gm = gram). Females were substantially heavier than males at 8 weeks of age (p < 0.01), but there was no significant difference in body weights between the two types of ducks (p > 0.05) until the 12th week of age (p < 0.01). Deshi black and Deshi white ducks reached sexual maturity at 136.0 ± 0.52 and 139.0 ± 0.52 days, respectively, and had 67.62 ± 0.83% and 63.18 ± 0.83%, 63.63 ± 0.56%, and 59.42 ± 0.56% fertility. Deshi black ducks had a substantially higher age at sexual maturity, fertility, and hatchability percentage (%) than Deshi white ducks (p < 0.01). For Deshi black and Deshi white, the egg weight, female weight at 1st lay, and egg weight at 1st lay were 66.69 ± 0.49 gm and 66.78 ± 0.49 gm, 1439.55 ± 6.98 gm and 1422.0 ± 6.98 gm, 48.90 ± 0.18 gm and 47.12 ± 0.18 gm, respectively. Deshi black duck egg weight was considerably (p < 0.01) higher than Deshi white duck egg weight at first lay. Deshi black and Deshi white ducks produced 214.65 and 211.402.65 eggs per year, respectively (p > 0.05). The study's findings gave some baseline information on Bangladesh's Deshi black and Deshi white ducks, which could benefit conservation and future enhancement efforts.

Evaluation of Correlations and Cluster Analysis of Genetic Variants, Heritability, and Genetic Advances Using Mutagens Driven Ten Variants of Brassica Campestris

The review was taken up to appraise genotypic and phenotypic changeability, heritability with hereditary development, relationship, and bunch examination on development and yield boundaries in 10 variations of assortment T-9 of Brassica campestris (toria). These variations were acquired through mutagenesis. Examination of change uncovers that there are profoundly massive contrasts among every one of the characteristics considered. Completely, phenotypic coefficients of fluctuation were higher than their separate genotypic coefficients of change for every one of the characteristics. High GCV was noticed for cases plant-1, snout length, and seed yield plant-1 while most noteworthy PCV was displayed for auxiliary branches plant-1. Expansive sense heritability went from most reduced 16.41 for auxiliary branches per plant to most noteworthy 72.35 for plant level. Units plant-1, plant level, mouth length, case length, and seed yield plant-1 showed high hereditary development over mean percent. The consequences of connection uncovered that seed yield plant-1 showed an exceptionally huge positive relationship with stem border, optional branches, cases on a fundamental raceme, unit plant-1, and 100 seed weight, albeit critical negative connection with bill length. The attributes which showed a positive connection with seed yield were the fundamental supporter of high seed yield plant-1. All genotypes were assembled into two groups at 3% linkage. Bunch I contains variations with a most extreme mean incentive for plant level, raceme length, and case length though group II genotypes showed high mean incentive for unit plant-1, 100 seed weight, and seed yield plant-1. The consequence of hereditary uniqueness in variations shows that it is useful in the choice of prevalent yield credits in the rearing system of oilseed Brassicas.

Behavioural and morphological traits influence sex-specific floral resource use by hummingbirds.

Research on resource partitioning in plant-pollinator mutualistic systems is mainly concentrated at the levels of species and communities, whereas differences between males and females are typically ignored. Nevertheless, pollinators often show large sexual differences in behaviour and morphology, which may lead to sex-specific patterns of resource use with the potential to differentially affect plant reproduction and diversification. We investigated variation in behavioural and morphological traits between sexes of hummingbird species as potential mechanisms underlying sex-specific flower resource use in ecological communities. To do so, we compiled a dataset of plant-hummingbird interactions based on pollen loads for 31 hummingbird species from 13 localities across the Americas, complemented by data on territorial behaviour (territorial or non-territorial) and morphological traits (bill length, bill curvature, wing length and body mass). We assessed the extent of intersexual differences in niche breadth and niche overlap in floral resource use across hummingbird species. Then, we tested whether floral niche breadth and overlap between sexes are associated with sexual dimorphism in behavioural or morphological traits of hummingbird species while accounting for evolutionary relatedness among the species. We found striking differences in patterns of floral resource use between sex. Females had a broader floral niche breadth and were more dissimilar in the plant species visited with respect to males of the same species, resulting in a high level of resource partitioning between sexes. We found that both territoriality and morphological traits were related to sex-specific resource use by hummingbird species. Notably, niche overlap between sexes was greater for territorial than non-territorial species, and moreover, niche overlap was negatively associated with sexual dimorphism in bill curvature across hummingbird species. These results reveal the importance of behavioural and morphological traits of hummingbird species in sex-specific resource use and that resource partitioning by sex is likely to be an important mechanism to reduce intersexual competition in hummingbirds. These findings highlight the need for better understanding the putative role of intersexual variation in shaping patterns of interactions and plant reproduction in ecological communities.

Habitat-linked genetic variation supports microgeographic adaptive divergence in an island-endemic bird species.

We investigated the potential mechanisms driving habitat‐linked genetic divergence within a bird species endemic to a single 250‐km2 island. The island scrub‐jay (Aphelocoma insularis) exhibits microgeographic divergence in bill morphology across pine–oak ecotones on Santa Cruz Island, California (USA), similar to adaptive differences described in mainland congeners over much larger geographic scales. To test whether individuals exhibit genetic differentiation related to habitat type and divergence in bill length, we genotyped over 3000 single nucleotide polymorphisms in 123 adult island scrub‐jay males from across Santa Cruz Island using restriction site‐associated DNA sequencing. Neutral landscape genomic analyses revealed that genome‐wide genetic differentiation was primarily related to geographic distance and differences in habitat composition. We also found 168 putatively adaptive loci associated with habitat type using multivariate redundancy analysis while controlling for spatial effects. Finally, two genome‐wide association analyses revealed a polygenic basis to variation in bill length with multiple loci detected in or near genes known to affect bill morphology in other birds. Our findings support the hypothesis that divergent selection at microgeographic scales can cause adaptive divergence in the presence of ongoing gene flow.

Sociality and morphology differentiate niches of 13 sympatric Amazonian woodcreepers (Dendrocolaptinae)

Abstract Woodcreepers (Dendrocolaptinae) represent a remarkably uniform group of brownish birds that move by hitching up tree trunks as they forage for arthropod prey. Despite these superficial similarities, we were able to uniquely differentiate the niches of all 13 species north of Manaus by integrating morphological traits (e.g., mass and bill size) with behavioral traits (e.g., sociality, stratum use, and foraging maneuvers). The 5 ant-following (myrmecophilous) species, with their larger bodies and heavier bills, were morphologically distinct from the 7 species that join mixed-species flocks. A combination of vertical stratum, mass, and bill length further distinguished among mixed-flocking species. Two canopy species—the solitary Dendrexetastes rufigula and the mixed-flocking Lepidocolaptes albolineatus—consistently foraged at higher strata than other species. For the remaining mixed-flocking species, the largest 3 species differed significantly by mass, whereas the smallest 3 species, which overlapped broadly in mass, were uniquely distinguished by bill length. The 5 ant-following species differed in their degree of specialization on ant swarms, from facultative (Hylexetastes perrotii) to obligate (Dendrocincla merula). The ant-followers also showed nearly discrete mass distributions that essentially differed by Hutchinsonian 1:1.3 ratios, which likely allows them to maintain interspecific dominance hierarchies at the front of raiding army ant swarms. The behaviors we quantified (sociality, vertical strata, and myrmecophily), together with morphology (mass and bill size), separated all 13 species. We speculate that niche partitioning and competitive exclusion allow each woodcreeper to uniquely access invertebrate prey, permitting coexistence and contributing to high alpha diversity at our study site.

The evolution, ecology, and conservation of hummingbirds and their interactions with flowering plants.

The ecological co-dependency between plants and hummingbirds is a classic example of a mutualistic interaction: hummingbirds rely on floral nectar to fuel their rapid metabolisms, and more than 7000 plant species rely on hummingbirds for pollination. However, threats to hummingbirds are mounting, with 10% of 366 species considered globally threatened and 60% in decline. Despite the important ecological implications of these population declines, no recent review has examined plant-hummingbird interactions in the wider context of their evolution, ecology, and conservation. To provide this overview, we (i) assess the extent to which plants and hummingbirds have coevolved over millions of years, (ii) examine the mechanisms underlying plant-hummingbird interaction frequencies and hummingbird specialization, (iii) explore the factors driving the decline of hummingbird populations, and (iv) map out directions for future research and conservation. We find that, despite close associations between plants and hummingbirds, acquiring evidence for coevolution (versus one-sided adaptation) is difficult because data on fitness outcomes for both partners are required. Thus, linking plant-hummingbird interactions to plant reproduction is not only a major avenue for future coevolutionary work, but also for studies of interaction networks, which rarely incorporate pollinator effectiveness. Nevertheless, over the past decade, a growing body of literature on plant-hummingbird networks suggests that hummingbirds form relationships with plants primarily based on overlapping phenologies and trait-matching between bill length and flower length. On the other hand, species-level specialization appears to depend primarily on local community context, such as hummingbird abundance and nectar availability. Finally, although hummingbirds are commonly viewed as resilient opportunists that thrive in brushy habitats, we find that range size and forest dependency are key predictors of hummingbird extinction risk. A critical direction for future research is to examine how potential stressors - such as habitat loss and fragmentation, climate change, and introduction of non-native plants - may interact to affect hummingbirds and the plants they pollinate.

Comparative study on morphometric traits of local chicken (gallus domesticus L.) in wilaya of Adrar

A study was conducted in the wilaya of Adrar in Algeria (a part of Sahara) to describe the phenotype and morphometric characteristics of local chickens. Six regions namely (part of the wilaya of Adrar) Tamentit, Zawyet Elkenta, Wlad Ahmed, Adrar city, Anezjmir and Founoghil were selected for data collection. A field survey was used to extract information from the farmers concerning production attributes of their local chickens. Measurements on body weight, tarsal length and width, high Length, thigh width, bill length, spout width, total length, breast width and eggs number per year were taken on 89 mature chickens (69 females and 20 males). The results obtained indicate that there exists significant variation between regions with respect to some production attributes as well as body weight and other body measurements. Fonoughil and Adrar city regions had the heaviest chickens (2.54kg-2.40kg respectively) while Zawyet Elkenta had the lightest birds (1.8kg). Overall, male chickens were higher than female birds with respects to all attributes studied. Body weight appeared to be highly positively correlated to some other body measurements considered in this study. The observed variation about the morphometric traits in the present study illustrate by the principal component analysis suggests that there are two groups, the first of which is represented by individuals from the Adar city region, in the other hand the second grouped all the rest of the 5 regions. There is need to pay particular attention to the Adrar city region chicken population for possible consideration for conservation and selection plan.

Sexually dichromatic hybrids between two monochromatic duck species, the Chiloé wigeon and the Philippine duck.

Captive bird hybrids can provide important data on certain traits, such as hybrid viability and fertility. In this paper, we describe four hybrids between the Chiloé wigeon (Anas sibilatrix) and the Philippine duck (Anas luzonica). These two species diverged about 13 million years ago and are found on different continents, making the occurrence of wild hybrids extremely unlikely. Hence, these captive hybrids provide a unique opportunity to learn more about the outcome of hybridization between these highly divergent species. One pair of hybrids mated and produced six unfertilized eggs, suggesting that hybrids between these species are infertile. Morphologically, the hybrids were slightly larger than the parental species, but had intermediate bill lengths. With regard to plumage patterns, the hybrids displayed characteristics of both parental species: Males developed the iridescent green head pattern of the Chiloé wigeon, whereas the females showed the dark crown and eye stripe of the Philippine duck. Interestingly, Chiloé wigeon and Philippine duck are both sexually monochromatic whereas the hybrids showed clear sexual dimorphism. These hybrids can thus lead to novel insights into the genetic and developmental basis of sexual mono‐ and dichromatism in ducks.

Exploration speed in captivity predicts foraging tactics and diet in free-living red knots.

Variation in foraging tactics and diet is usually attributed to differences in morphology, experience and prey availability. Recently, consistent individual differences in behaviour (personality) have been shown to be associated with foraging strategies. Bolder or more exploratory individuals are predicted to have a faster pace‐of‐life and offset the costs of moving more or in risky areas, with higher energetic gains by encountering profitable foraging opportunities and prey. However, the relationship between personality, foraging and diet is poorly understood.We investigated how exploratory behaviour in red knots Calidris canutus is associated with foraging tactics and diet by combining laboratory experiments, field observations and stable isotope analysis. First, we developed a mobile experimental arena to measure exploration speed in controlled settings. We validated the method by repeated testing of individuals over time and contexts. This setup allowed us to measure exploratory personality at the field site, eliminating the need to bring birds into captivity for long periods of time. After releasing birds within days of their capture, we asked whether exploration speed was associated with differences in foraging tactics and diet in the wild.We found that tactile foraging red knots mainly caught hard‐shelled prey that are buried in the sediment, whereas visual foraging knots only captured soft preys located close to or on the surface. We also found that faster explorers showed a higher percentage of visual foraging than slower explorers. By contrast, morphology (bill length and gizzard size) had no significant effect on foraging tactics. Diet analysis based on δ15N and δ13C stable isotope values of plasma and red blood cells confirmed our field observations with slower explorers mainly consumed hard‐shelled prey while faster explorers consumed more soft than hard‐shelled prey.Our results show that foraging tactics and diet are associated with a personality trait, independent of morphological differences. We discuss how consistent behaviour might develop early in life through positive feedbacks between foraging tactics, prey type and foraging efficiency.

PREFORMATIVE MOLT EXTENT AND AGING AND SEXING CRITERIA FOR EIGHT HUMMINGBIRD SPECIES IN SOUTHEASTERN PERU

Little attention has been paid to molt and age criteria in hummingbirds despite the importance of molt and age to numerous behavioral and ecological questions. We examined age-based molt patterns and bill corrugations in eight species of lowland Amazonian hummingbirds. Molt strategies and rates of bill smoothing were similar to those of more well-studied North American species, with all species showing partial preformative molts (replacing only body feathers and some wing coverts and retaining all remiges and rectrices), and bill corrugations reducing to less than 10% of bill length in all species during the first annual cycle. Several species showed evidence of delayed maturation in males in regard to plumage characteristics or bill coloration.