Changes In Wing Length Research Articles

Increasing winter temperatures explain body size decrease in wintering bird populations of Northern Europe—But response patterns vary along the spatioclimatic gradient

AbstractAimRecent evidence has shown changes in body size and shape of individuals, which are suggested to be a result of global warming caused by climate change. Here, we explored the spatiotemporal changes in wing length and body mass of 24 wintering bird species in Northern Europe and how these relate to temperature anomaly.LocationFinland and Sweden, Europe.Time Period50 years, 1970 to 2020.Major Taxa StudiedBirds, 24 species.MethodsWe used site‐specific, long‐term winter ringing data containing wing length and body mass measurements from across Sweden and Finland for 24 bird species. We modelled wing length and body mass change over time, in relation to the spatioclimatic gradient and as response to temperature anomalies (of [i] the same winter as the ringing took place, [ii] the previous winter and [iii] the previous spring) by accounting for phylogenetic relatedness between species and their species‐specific responses to each predictor of interest.ResultsWe show that across all species, body size has decreased since the 1970s, with a negative relationship between wing length and temperature anomalies of previous winters, suggesting carry‐over effects likely linked to body size‐related survival or dispersal. Body mass was negatively related to the temperature anomaly of the same winter, indicating more immediate effects related to reduced fat reserves during mild winters.Main ConclusionsOur results highlight a climate‐driven decrease in body size across several species and its association with positive anomalies in winter temperature in the high latitudes. However, the responses are not spatially uniform and there is considerable species‐specific variation, emphasizing the importance of conducting multispecies studies when investigating responses to climate change. The mechanisms of decreasing wing length and body mass seem to differ and underline the immediate and carry‐over effects of temperature warming during the nonbreeding season.

Widespread recent changes in morphology of Old World birds, global warming the immediate suspect

AbstractAimA decline in body size has been proposed as a universal response to global warming, but this is often questioned. We describe and characterize recent morphological changes in the avifauna of Israel as a whole and test several hypotheses regarding their cause.LocationIsrael.Time period1950–2020.Major taxa studiedAves.Methods We analysed the morphology of 7,981 museum specimens. For each of the 106 species, we calculated the rate of change in mass, head and body length, wing length and approximate relative surface area, both over time and as a function of temperature anomaly (the difference between temperatures in a given year and the interannual average). We used phylogenetic generalized linear mixed models (PGLMMs) to determine trends and their relationship to the ecology of species.ResultsOver the last 70 years there have been consistent changes through time in mass, length and surface area‐to‐volume ratio. Mass decreased by 18.3%, length increased by 5.1%, and surface area‐to‐volume ratio increased by 28.9%. The increase in the ratio of surface area to volume through time corresponds to a 12.2% increase per degree Celsius of warming. In contrast, changes in wing length were few and inconsistent. Most species changed in either mass or length, but seldom in both. The effect of rising temperature on morphology was roughly an order of magnitude stronger than the effect of a comparable geographical difference in habitat temperature. Changes were modulated by migratory habits but not explained by human commensalism or diet.Main conclusionsA decrease in mass and increase in length are widespread, both leading to higher relative surface area. Results conform with predicted responses to global warming, but not with any of our other tested hypotheses. If warming is the driver of these changes, the diverging responses observed between different species might represent different solutions to solve a common problem.

Shifts in phenology of autumn migration and wing length among reedbed passerines along the East Asian–Australasian Flyway

Climate change impacts bird migration phenology, causing changes in departure and arrival dates, leading to potential mismatches between migration and other key seasonal constraints. While the impacts of climate change on arrival at breeding grounds have been relatively well documented, little is known about the impacts of climate change on post-breeding migration, especially at stopover sites. Here we use long-term (11 years) banding data (11,118 captures) from 7 species at Mai Po Marshes Nature Reserve in Hong Kong, a key stopover site for migratory birds along the East Asian–Australasian Flyway, to describe long-term changes in migration phenology and to compare observed changes to annual weather variation. We also examine changes in wing length over a longer time period (1985–2020) as wing length often correlates positively with migration distance. We found that observed changes in migratory phenology vary by species; three species had later estimated arrival (by 1.8 days per year), peak (by 2.6 days per year) or departure (by 2.5 days per year), one showed an earlier peak date (by 1.8 days per year) and two showed longer duration of passage (2.7 days longer and 3.2 days longer per year). Three species exhibited no long-term change in migration phenology. For two of the four species with shifting phenology, temperature was an important predictor of changing peak date, departure dates and duration of passage. Wing length was shorter in three species and longer in two species, but these changes did not correlate with observed phenological changes. The complex changes observed here are indicative of the challenges concerning the detection of climate change in migratory stopover sites. Continued monitoring and a better understanding of the dynamics of all sites in the migratory pathway will aid conservation of these species under global change.

Temporal Changes in Wing Length, Fat Reserves and Body Mass of Migrating Eurasian Blackcaps Sylvia atricapilla at a West Hungarian Stopover Site

Changes in biometric characteristics of a migrating bird population at a given capture site could reflect that the migration strategies of the species may be changing. A robust data set (15,520 records) was used to analyse the changes in biometric characteristics of the Eurasian Blackcap Sylvia atricapilla in western Hungary between August and October during the study period (2001–2019). All age and sex classes displayed similar phenology of monthly captures and biometric change: the average wing length, fat score and body mass increased in the migrating population from August to October. This could be explained by changes in the morphometric distribution of different migrating populations, in later months more birds might arrive from a larger distance, primarily from the Baltic regions and the Czech Republic. The biometrics of juvenile birds captured in August did not change significantly from 2001 to 2019, while the wing lengths decreased and fat scores increased significantly between 2001 and 2019 in September and October in both sex classes. This could be explained by a change in the migration distance or different morphology of individuals from the north which stopped over at the study area. Due to the global warming and habitat changes in the last decade, the shorter migration route and favourable conditions at overwintering areas north of the Sahara or around the Mediterranean could favour Blackcaps which migrate a shorter distance.

Age-dependent changes in biometrics indicate senescence in the European Blackbird Turdus merula

ABSTRACTCapsule: A 19-year study of European Blackbirds Turdus merula confirms that senescence is associated with a decrease in condition measured by wing length but bills become progressively longer with age.Aims: To explore the correlations between biometrics of Blackbirds and age, to identify possible links with senescence.Methods: During the 19 years of the study, 801 birds of known age were measured: 431 males and 370 females, aged from 2 to 10 years. Among these 91 males and 50 females were retrapped at least one moult later. For each bird, there were at least one set of measurements when fully grown.Results: Wing length increased until the sixth year of life after which it started to decrease. An increase in bill length throughout the lifetime was found in both sexes.Conclusion: Changes in wing length correspond with an earlier study of this population suggesting the onset of senescence after the fifth to sixth calendar year of life.

Long-term continental changes in wing length, but not bill length, of a long-distance migratory shorebird.

We compiled a >50‐year record of morphometrics for semipalmated sandpipers (Calidris pusilla), a shorebird species with a Nearctic breeding distribution and intercontinental migration to South America. Our data included >57,000 individuals captured 1972–2015 at five breeding locations and three major stopover sites, plus 139 museum specimens collected in earlier decades. Wing length increased by ca. 1.5 mm (>1%) prior to 1980, followed by a decrease of 3.85 mm (nearly 4%) over the subsequent 35 years. This can account for previously reported changes in metrics at a migratory stopover site from 1985 to 2006. Wing length decreased at a rate of 1,098 darwins, or 0.176 haldanes, within the ranges of other field studies of phenotypic change. Bill length, in contrast, showed no consistent change over the full period of our study. Decreased body size as a universal response of animal populations to climate warming, and several other potential mechanisms, are unable to account for the increasing and decreasing wing length pattern observed. We propose that the post‐WWII near‐extirpation of falcon populations and their post‐1973 recovery driven by the widespread use and subsequent limitation on DDT in North America selected initially for greater flight efficiency and latterly for greater agility. This predation danger hypothesis accounts for many features of the morphometric data and deserves further investigation in this and other species.

Neotropical Migrants Exhibit Variable Body-Size Changes Over Time and Space

Abstract Recent changes in the Earth's climate have been linked to changes in phenology, geographic distributions, and morphology of species, and warming temperatures associated with climate change have been predicted to result in decreases in avian body sizes. We examined changes in wing length and fat-free mass of 34,844 fall migrants from 31 neotropical migratory species captured at Patuxent Wildlife Research Center in Maryland between 1980 and 2012. Body size changes varied across species, but wing length and fat-free mass increased significantly over time in the pooled sample of all species. Magnitudes of change were small and similar to other studies, with mean wing length increasing 0.55% and mean fat-free mass increasing 1.30% across all species. General morphological changes at our site differed from those at a banding station located 235 km away. Across species, changes in wing length were weakly correlated between stations, and changes in fat-free mass were uncorrelated. Populations of some spe...

BlackcapsSylvia atricapillaon Migration: A Link between Long-Term Population Trends and Migratory Behaviour Revealed by the Changes in Wing Length

Recent climate change has a major impact on the sizes and distribution of bird populations, the phenology of their breeding/migration and migratory behaviour (migration distance, migration strategy). We documented changes in the numbers of juvenile Blackcaps migrating in autumn through the S Baltic that were paralleled by changes in wing length of captured individuals during a 43-year study period (1967–2009). We suggest that the observed trends may indicate changing population composition of migrating birds. In the Blackcap, wing length distinguishes among different populations and increases with increasing migration distance of a given population. Available published data show that long-distance and short-distance Blackcaps pass the study region. Hence, we assumed that shorter-winged birds are short-distance migrants wintering in the southern Europe, and that longer-winged individuals are long-distance migrants wintering in the sub-Saharan region. It seems that in 1967–1980 most Blackcap populations declined, but, as wing length slightly increased, the rate of this decline has been higher in the shorter-winged/short-distance Blackcaps. Over the subsequent 24 years alongside with rapidly growing numbers of birds, we noted a remarkable decrease in wing length. This indicates a pronounced increase in the number of short-distance individuals compared to long-distance migrants. Both groups may benefit from improved conditions at their breeding grounds, but the shorter migration route and favourable conditions at wintering sites north of Sahara could favour short-distance migrants over the longer distance and longer-winged Blackcaps.

Heterogeneous changes in avian body size across and within species

Contemporary climate change has been linked to widespread changes in phenology and in the geographic distribution of species. Based on Bergmann’s rule, body sizes of birds have been predicted to decline as global temperatures increase. We examined changes in body size of 20 resident and short-distance migrant passerine species in eastern North America between 1980 and 2012, and how changes in resident species related to annual mean summer and mean winter temperatures. We found that wing length generally increased and that fat-free mass did not change significantly. Fat score, a measure of body condition, declined over time. However, changes in wing length, fat-free mass, and fat score all showed significant variation across species. For resident species, increasing mean summer temperatures were generally associated with shorter wing lengths, but were not related to fat-free mass or fat score. Increasing mean winter temperatures were associated with reduced fat-free mass but not with wing length or fat score. Temperature effects did not vary significantly across species for any of the three measures. Across resident species, the magnitude of body size change over time was not related to the influence of mean winter or mean summer temperatures, and may have been driven by other factors. Our findings contrast with those from a study at a nearby bird banding station, in which widespread decreases in wing length and fat-free mass were observed. Our results demonstrate that populations of the same species can exhibit opposing changes in body size over short geographic distances (<250 km). We conclude that changes in body size are heterogeneous over short time scales and can vary across and within species over short distances. Continued advances in understanding how body size changes relate to climate change must embrace this inherent complexity and consider alternative hypotheses.

Longitudinal data reveal ontogenetic changes in the wing morphology of a long‐distance migratory bird

In migratory bird species, juveniles normally have shorter and more rounded wings than adults. The causes of this age‐specific difference in wing morphology, however, are largely unknown. Here, we used longitudinal data collected over 3 years from a Pied Flycatcher Ficedula hypoleuca population to assess whether age‐related differences in wing morphology are a consequence of ontogenetic changes or of selection favouring birds with longer and more pointed wings. Our study provides evidence of ontogenetic changes in wing length and shape, whereby birds grow longer and more pointed wings as they grow older. Age‐dependent variation is likely to be adaptive and may partly explain age differences in spring migration phenology and breeding success.

A 48,000 year record of swiftlets (Aves: Apodidae) in North-western Borneo: Morphometric identifications and palaeoenvironmental implications

This paper reports the results of an analysis of 508 sub-fossil carpometacarpi of swiftlets (Aves: Apodidae) recovered during archaeological excavations of the Great Cave of Niah in Sarawak, North-western Borneo. The bones date from 48kyBP (ky BP: 103 calibrated years before present [1950]) to 0.35kyBP and provide a means to consider populations of birds (of which one species is a significant commercial interest) in the context of environmental and climatic change in the past, and their responses to recent anthropogenic landscape changes in the present.Biometric analyses and comparative data indicate that the collection contained specimens attributable to the three extant species of swiftlet that currently inhabit the Great Cave: the black-nest swiftlet (Aerodramus maximus), mossy-nest swiftlet (Aerodramus salanganus) and the white-bellied swiftlet (Collocalia esculenta). A subset of 267 identified specimens provides a time series that suggests that the Great Cave and environs have sustained populations of these three species throughout last 48,000years. While changes in the wing length of extant species of swiftlet are known as a function of geographical and altitudinal range, statistical testing of a single character (greatest length of the carpometacarpus) did not indicate changes in wing length in any of the identified species.The findings indicate that the local environs maintained a sufficient abundance of aerial arthropods to support populations of these obligate insectivores and are consistent with studies that suggest that the structural diversity of forest habitats was maintained throughout the late Pleistocene (48kyBP to 11.6kyBP) and Holocene (11.6kyBP to 0.35kyBP). The findings also provide context for the recent declines of the commercially-significant black-nest swiftlet and suggest that this species may be ill-equipped to adapt to recent anthropogenic deforestation of the Niah area.

Changes in wing length in the pollinator Bombus dahlbomii occurring with the fragmentation of the Maulino forest, Chile

La fragmentacion del habitat puede afectar el diseno morfologico de los insectos voladores de distintas maneras, a traves de cambios en los costos y beneficios de los patrones de dispersion. Como resultado, es probable que alas mas grandes puedan ser favorecidas cuando los recursos necesarios se encuentren dispersos a lo largo del paisaje fragmentado. En esta investigacion se puso a prueba esta prediccion en Bombus dahlbomii (Guerin), un polinizador nativo de Chile asociado al bosque Maulino fragmentado. Mediante trampas colgantes, se capturaron individuos en el bosque nativo continuo, en cuatro pequenos fragmentos y en dos plantaciones de Pinus radiata (matriz). A cada individuo colectado se le midio su tamano corporal (mm) y el largo de su primer y segundo par de alas (mm). En total, fueron capturados 280 individuos. El tamano corporal y el largo de ambos pares de alas fue mayor en los fragmentos y en la matriz, en comparacion con el bosque continuo. Ademas, se observo una relacion positiva y significativa entre la longitud de las alas y el tamano corporal en todos los habitats, sin embargo, la varianza explicada fue menor en el bosque continuo que en los fragmentos y la matriz. Estos resultados sugieren que la fragmentacion del bosque Maulino podria favorecer fenotipos con alas mas grandes, probablemente con mayores capacidades de vuelo para la busqueda de recursos escasos durante el forrajeo.

Ecomorphology of the External Flight Apparatus of Blackcaps (Sylvia atricapilla) with Different Migration Behavior

An analysis of the external flight apparatus of 700 blackcaps from eight different populations (sedentary to long-distance migrators) is presented. With increasing migration distances of populations, (1) wing length, aspect ratio, and wing pointedness increase; (2) wing load decreases; (3) slots on the wing tips become relatively shorter; (4) the alula tends to be shorter in relation to wing length; and (5) the tail is shorter in relation to wing length. Although body mass increases from southern to northern populations, changes in wing length and wing area are two to three times larger than expected for simple isometric relationships. Regarding the aerodynamic background of these changes, it can be stated that traits for energy-effective flight are more strongly developed and traits for maneuverability are less developed in birds traveling longer distances, presumably as a consequence of trade-offs. Nonmigratory blackcaps from Madeira and the Cape Verde islands do not always show the traits we would expect in view of their sedentary behavior. This can be seen as a result of recent colonization of these islands by migrants or of selection by factors other than migration behavior. In migratory populations, changes between the first and the second set of primaries during first complete molt show almost the same pattern as the changes from nonmigratory to migratory populations. During molt of the primaries, blackcaps of nonmigratory populations do not show these changes. Hybrids between migrating and nonmigrating blackcap populations (Moscow and Madeira) showed intermediate values between parent populations in wing length, wing shape, and wing area; in the other variables they resembled either parent population.

Plastic and Genetic Variation in Wing Loading as a Function of Temperature Within and Among Parallel Clines in Drosophila subobscura

Drosophila subobscura is a European (EU) species that was introduced into South America (SA) approximately 25 years ago. Previous studies have found rapid clinal evolution in wing size and in chromosome inversion frequency in the SA colonists, and these clines parallel those found among the ancestral EU populations. Here we examine thermoplastic changes in wing length in flies reared at 15, 20, and 25°C from 10 populations on each continent. Wings are plastically largest in flies reared at 15°C (the coldest temperature) and genetically largest from populations that experience cooler temperatures on both continents. We hypothesize that flies living in cold temperatures benefit from reduced wing loading: ectotherms with cold muscles generate less power per wing beat, and hence larger wings and/or a smaller mass would facilitate fight. We develop a simple null model, based on isometric growth, to test our hypothesis. We find that both EU and SA flies exhibit adaptive plasticity in wing loading: flies reared at 15°C generally have lower wing loadings than do flies reared at 20°C or 25°C. Clinal patterns, however, are strikingly different. The ancestral EU populations show adaptive clinal variation at rearing a temperature of 15°C: flies from cool climates have lower wing loadings. In the colonizing populations from SA, however, we cannot reject the null model: wing loading increases with decreasing clinal temperatures. Our data suggest that selective factors other than flight have favored the rapid evolution of large overall size at low environmental temperatures. However, selection for increased flight ability in such environments may secondarily favor reduced body mass.

Long-Term Variability of Wing Length in a Population of the Reed WarblerAcrocephalus scirpaceus

Abstract. 4166 measurements of wing length in Reed Warblers were made during 9 breeding and pre-migratory periods in Central Poland. In the studied population there was significant differentiation in the wing length among seasons in adult and juvenile birds. Multiple regression and path analysis showed that weather factors (temperature and precipitation) during the breeding period determine the long-term variation in the wing length in both adult and young birds. Changes in wing length were explained by natural selection and habitat selection. In breeding and pre-migratory periods, temperature and precipitation influence in food availability, and thus affect optimisation of energetic expenses on feeding. It was revealed that long-winged individuals are best adapted to cold and rainy conditions, the short-winged ones, to warm and dry summers. The weather conditions obtaining when the birds arrive at the breeding grounds could be linked to differentiation in availability of optimal places for establishing t...

Feather mites, pectoral muscle condition, wing length and plumage coloration of passerines

I compared the feather mite (Acari, Proctophyllodidae) loads of moulting birds with features of the new plumage that they were growing. I examined 21 samples, each sample containing individuals of the same species, sex and age class (juvenile, yearling or adult). I used nine species: wren, Troglodytes troglodytes; dunnock, Prunella modularis; robin, Erithacus rubecula; blue tit, Parus caeruleus; great tit, P. major; chaffinch, Fringilla coelebs; greenfinch, Carduelis chloris; linnet, C. cannabina; and yellowhammer, Emberiza citrinella. As previously reported for the house finch, Carpodacus mexicanus, birds with more feather mites grew duller plumage and relatively shorter wings than less infested individuals of the same sex and age class. They also had lower protein reserves judged by the shape of their pectoral muscle. Mite load was usually a better predictor of coloration than pectoral muscle score, but the opposite was true for changes in wing length. In contrast to house finches, birds whose plumage was dull before moult had higher mite loads while moulting. Even if feather mites do not cause dull plumage or short wings, they appear to be a good indicator of birds in poor physiological condition.

Role of habitat components on the dynamics of Aedes albopictus (Diptera: Culicidae) from New Orleans.

Monthly sampling of tire pile populations of Aedes albopictus (Skuse) in Orleans Parish, New Orleans, LA, was done in 1995 to determine prevalence of ascogregarine parasites and changes in wing length. Prevalence of Ascogregarina taiwanensis (Lien & Levine) infection was 100% in midsummer and decreased in the fall and spring (60-70%). Wing lengths were longest in the spring and fall and shortest in midsummer. We evaluated the effect of A. taiwanensis infections under high and deficient levels of leaf litter nutrients on mortality, development time, wing length, and reproductive potential of a New Orleans strain of Ae. albopictus. Parasitism and deficient nutrients caused a 35% increase in the rate of larval mortality and significantly extended the development time of females. Parasitized adults were 5% smaller and produced 23% fewer eggs than unparasitized siblings. In addition, abnormal Malpighian tubule morphology and melanization of ascogregarines were seen in adults from nutrient-deficient microcosms. We conclude that ascogregarine infections affect the dynamics of Ae. albopictus by increasing the mortality of immature stages when nutrients supplies are scarce, and by decreasing the reproductive capacity of females under high nutrient conditions.

Buteo polyosoma and B. poecilochrous, the "Red-Backed Buzzards" of South America, Are Conspecific

The Puna Buzzard (= Variable Buzzard or Gurney's Buzzard, Buteo poecilochrous) and the Red-backed Buzzard (B. polyosoma) are two morphologically similar and closely related South American raptors that have been and are currently separated as species mainly on the basis of wing length and Stresemann's wing formula. I reexamined wing formula, wing length, geographic variables, and plumage in adults and immatures, and adult vocalizations. For both adults and immatures, wing formula and wing length are not reliable taxonomic characters because of their continuous clinal relationship. In both age classes, wing tip contour changes allometrically with changes in wing length, which is itself a function of body size and mass. Thus, neither of the currently accepted morphometric characters examined here serve to separate taxon polyosoma from taxon poecilochrous. There are at least 27 distinct adult plumage morphs (formerly five) in this species group, perhaps more than any other in Falconiformes, with no relationship to morphometric variables and only minor geographic variation. Immature plumages are similarly ineffective in diagnosing taxa. Vocalizations are similar among adults from widely varying latitudes and altitudes. I therefore propose dropping poecilochrous (Gurney 1879) in favor of polyosoma (Quoy and Gaimard 1824) for all forms in this group, as the latter has priority. The English common name applied to this group should be Variable Buzzard, with the exception of the isolated population in the Juan Fernandez Archipelago which should for now remain the Juan Fernandez Buzzard (B. p. exsul), although it may well be elevated to species rank with further data.

Oviposition habits of Simulium kawamurae (Diptera: Simuliidae), with reference to seasonal changes in body size and fecundity.

Oviposition habits and seasonal changes in wing length, head width, and number of ovarioles of Simulium kawamurae Matsumura were investigated in Kyushu Island, Japan. Gravid flies swarmed over turbulent water and laid eggs on rock surfaces in the splash zone. Large, irregular egg masses often resulted from the mass oviposition by many females within the same small area. Oviposition occurred at dusk during spring-summer, shifting to earlier periods during autumn-winter. Fecundity increased linearly as a function of body size (i.e., both with the cube of wing length and of head width, showing a better fit with the latter). Spring flies had a larger mean body size and fecundity than both summer and autumn flies. Winter flies had wings as long as spring flies, but their head widths and fecundity were comparable to summer-autumn individuals. This indicated seasonal variation in the relative proportion of body structures.