Primary Feather Length Research Articles

Effects of L-Methionine and DL-Methionine on Growth Performance, Methionine-Metabolizing Enzyme Activities, Feather Traits, and Intestinal Morphology of Medium-Growing, Yellow-Feathered Chickens between 1 and 30 Days of Age.

This experiment investigated the effects of L-Methionine (L-Met) on growth performance, Met-metabolizing enzyme activity, feather traits, and small intestinal morphological characteristics, and compared these with DL-Methionine (DL-Met) for medium-growing, yellow-feathered broilers during the starter phase. Furthermore, the aim was to provide recommendations for the appropriate dietary Met levels in feed. A total of 1584 1-d broilers were randomly divided into 11 treatment groups with six replicates of 24 birds each: basal diet (CON, Met 0.28%), basal diet + L-Met (0.04%, 0.08%, 0.12%, 0.16%, 0.20%), and basal diet + DL-Met (0.04%, 0.08%, 0.12%, 0.16%, 0.20%). The total trial period was 30 days. Compared with broilers fed the basal diet, those fed 0.04 to 0.20% supplemental Met had higher final body weight (FBW), average daily feed intake (ADFI), average daily gain (ADG), and lower feed-to-gain ratio (F: G) (p < 0.05). Compared with DL-Met groups, the L-Met group had higher FBW and ADG (p < 0.05). The relative bioavailability (RBV) of L-Met in ADG of 1-30 d was 142.5%. Chicks fed diets supplemented with L-Met had longer fourth primary feather lengths compared to birds fed the control and diets supplemented with DL-Met (p < 0.05). Compared to the control, birds supplemented with DL-Met or L-Met had an increased moulting score (p ≤ 0.05). Chicks fed diets supplemented with L-Met had lower activities of methionine adenosyl transferase (MAT) compared to those fed the basal diet or supplemented with DL-Met (p < 0.05). Chicks supplemented with either DL-Met or L-Met had higher activities of cystathionine β-synthase (CBS) than those fed the basal diet (p < 0.05). Compared with the control, chicks fed diets supplemented with either DL-Met or L-Met had an enhanced level of albumin in plasma (p < 0.05). There were no obvious differences in the plasma content of uric acid and total protein among the treatments (p > 0.05). Chicks fed diets supplemented with either DL-Met or L-Met had higher villus height and V/C in the duodenal than chicks fed the basal diet (p < 0.05). The jejunum morphology was not affected by either L-Met or DL-Met supplementation (p > 0.05). Therefore, dietary supplementation with DL-Met or L-Met improved the growth performance, feather traits, and intestinal morphological characteristics of medium-growing, yellow-feathered broiler chickens aged 1 to 30 d by decreasing the enzyme activities of Met methylation (MAT) and increasing the enzyme activities of the sulfur transfer pathway (CBS), and supplementation with L-Met showed a better improvement compared with DL-Met. The relative efficacy of L-Met to DL-Met was 142.5% for ADG of yellow-feathered broilers. The appropriate Met levels for medium-growing, yellow-feathered broilers are between 0.36~0.38% (supplementation with DL-Met) or 0.32~0.33% (supplementation with L-Met) when based on ADG and feed-to-gain ratio.

Revision of some mensural measurements, food preference, and haematological parameters in breeding pairs of blue rock pigeon, Columba livia sampled from punjab Pakistan

Abstract The present study describes the haematological profile, feeding preference, and comparison of morphometric characters of blue rock pigeon (Columba livia) breeding pairs. For this purpose, 25 pairs (25 samples per sex) were sampled through Mist nets from district Okara and Bahawalnagar, Punjab, Pakistan. Birds were then anaesthetized with a combination of ketamine HCL (10 mg/kg) and diazepam (0.2 mg/kg) and subjected to morphometric measurements. 5µL blood also was taken from the jugular vein of each anaesthetized bird for haematological analysis. Few pairs were also dissected to remove gastrointestinal tracts (GITs) for food preferences. Results revealed that there are no significant differences in the haematological parameters and feeding preference of breeding pairs of Columba livia. The gut analysis further revealed, the major portion of gut contents consisted of pea and corn in most of the pairs. Regarding the mensural measurements, significant differences were recorded in the body weight, length of the longest primary feather, and chest circumference, whereas the rest of the studied parameters remain nonsignificant between sexes. So, it is concluded that apart from 3 morphometric parameters (body weight, length of longest primary feather and chest circumference), both sexes are alike in term of morphometry, haematology and food preference.

Genome-wide association analysis of the primary feather growth traits of duck: identification of potential Loci for growth regulation

The feather is an important epidermal appendage, plays an important role in the life activities of avian specie, and has important economic value. Revealing the molecular regulation mechanism of feather growth has a significant meaning in studying adaptive evolution, physiology, and mating of avian species and also provides a theoretical reference for poultry breeding. In this study, the genome-wide association analysis (GWAS) of 358 ducks was based on primary feather length phenotypic data (28-60 d), length growth rates (LGRs), and maturity scores (60 d) to explore the genetic basis affecting feather growth and maturation. The results showed that, among the primary feather 1 to 5 in ducks, the mean LGR of primary feather 2 was the fastest, with the longest length. The primary feathers in males grew and matured slightly faster than in females. The mean maturity scores of primary feather 10∼7 were higher than primary feather 1 to 3 in ducks. GWAS further showed 116 SNPs associated with feather length traits. In addition, 2 candidate regions (Chr1: 127,407,230-127,524,879 bp and Chr21: 182,061,707-183,616,298 bp) were associated with LGR, which contain total 13 candidate genes (The extremely significant SNPs were mainly located in 2 genes: Chr1: REPS2 and Chr21: PTPRT). Four candidate regions (Chr1: 29,113,036-28,675,018 bp, Chr2: 18,253,612-149,111,290 bp, Chr15: 6,489,774 to 12,138,221 bp and Chr21: 6,578,021-8,472,904 bp) were associated with feather maturity, which contain total 24 candidate genes (The extremely significant SNPs were mainly located in 4 genes: Chr1: IMMP2L, DOCK4 and DDX10, Chr2: LDLRAD4). In conclusion, sex factors influence feather growth and maturity, and the genetic basis of the growth /maturity trait between different feathers is similar. REPS2, PTPRT genes, and IMMP2L, DOCK4, DDX10, and LDLRAD4 are important candidate genes that influence feather growth and maturity, respectively.

Revision of common snipe, Gallinago gallinago in morphometric analysis and building the standard reference haematological values for further studies

This study was designed to record some morphometric and haematological parameters of common snipe, Gallinago gallinago. For this purpose, 20 individuals (10 male, 10 female) were collected from the wetlands of District Bahawalnagar, Punjab, Pakistan. Significant differences between the sexes were recorded in tail length, length of longest primary feather, and chest circumference. . No significant difference was recorded in haematological parameters between the sexes. Gut analysis revealed that common snipe feed mostly on Chironomidae and Ceratopogonidae larvae and male and female snipes have the same food preference.

Feather growth, bodyweight and body temperature in broiler lines with different feathering rates

Two early feathering sire lines (B1 and B2), two late feathering dam lines (A1 and A3), and an early feathering dam line were evaluated to determine differences in growth, in lengths of primary feathers, in under-wing and rectal temperatures, and in feed intake until the birds were 20 weeks old. The chicks were hatched from eggs collected from 35-week-old hens of pure line broiler flocks. Data were collected at hatch, and at 1, 2, 4, 6, 8, 12, and 20 weeks old Thirty males and 30 females were evaluated for each line. The early feathering genotypes (A2, B1 and B2) had longer primary feathers until they were six weeks old. They also had higher under-wing and rectal temperatures and higher live weight compared with the late-feathering lines (A1 and A3) at one and two weeks old. The males were heavier than females at all ages. However, under-wing and rectal temperatures were similar in males and females at all ages. A positive correlation was observed between the length of primary feathers and live weight in A2, B1, and B2 at six weeks, whereas a negative correlation was observed between the rectal temperature and the length of primary feathers in A1 and A3 at 4 and 20 weeks old.

A revision of bird skin preparation aimed at improving the scientific value of ornithological collections

The methods used to preserve bird skins in museums have a potentially crucial impact on the feasibility and use of these specimens as a source of biological knowledge, although this subject is rarely broached. Study skins of birds are usually prepared with folded wings and straight legs to facilitate storage in the collection; yet, this method can hamper the measurement and examination of certain important features such as wing-feather moult. To make consultation easier for ornithologists, alternative preparation methods such as the splitting of wings and tarsi from the rest of the animal have been proposed by curators. Our aim was to study whether or not preparing bird specimens with spread limbs makes consultation simpler. First, we used two different methods to prepare two specimens each of two common European passerine species: (1) ‘traditional’ (folded wings and straight tarsi) and (2) ‘spread’ (limbs spread on one side of the body). Then, we asked 22 experienced ornithologists to identify moult limits and take three biometric measurements (wing chord, length of the third primary feather and tarsus length) from all four specimens. Subsequently, we asked which preparation method they preferred for obtaining data. The ‘spread’ preparation was preferred for moult, third primary feather length and tarsus length, whilst the ‘traditional’ preparation was preferred for wing chord. Data obtained from the folded and spread preparations were very highly repeatable within each method but only moderately to highly repeatable between methods. One of the handicaps with the ‘spread’ preparation is the increase in storage space required, a factor that should be taken into account before it is employed. Nevertheless, this specimen preparation technique can greatly facilitate consultation and therefore improve the scientific value of ornithological collections.

Dietary resistant potato starch improves growth performance and feather development in Pekin ducks fed a low phosphorus diet

This study investigated whether dietary resistant potato starch (RPS) inclusion could ameliorate the negative impact of a low nonphytate phosphorus (nPP) diet on growth performance, feather growth, feather follicles (FF) development, and carcass traits by improving nutrient utilization and cecal microbiome fermentation capacity in Pekin ducks. The experiment was performed with a 2 × 2 randomized block design with 2 levels of RPS (0 or 12%) and 2 levels of nPP (low or normal, low: 0.22% at 1–14 d and 0.18% at 15–35 d of age; normal: 0.40% at 1–14 d and 0.35% at 15–35 d of age) for a total of 4 treatments, each with 8 replicate pens per treatment of 12 birds per pen. As regards growth performance and carcass traits, RPS inclusion markedly increased (P < 0.05) BW of 14 and 35 d, BWG and FI of 1–14 d, 15–35 d, and 1–35 d as well as abdominal fat and breast meat percentage of 35 d in ducks fed low nPP diets; moreover, RSP inclusion significantly reduced (P < 0.05) mortality in ducks fed low nPP diets. As regards feather growth and follicles development of 35 d, RPS inclusion significantly increased (P < 0.05) the fourth primary feather length, absolute feather weight, and the density of primary FF in the back skin in ducks fed low nPP diets. In regard to nutrition utilization, RPS supplementation significantly increased (P < 0.05) the availability of DM, CP, and energy, as well as dietary AME at 35 d of age in ducks fed low nPP diets. However, RPS supplementation had no effect (P > 0.05) on the concentration of cecal short-chain fatty acids and the activities of cecal phytase and cellulase in ducks fed low nPP diets. These results indicate that RPS can improve nutrient availability to ameliorate the negative effects on performance and feather development caused by a low nPP diet in Pekin ducks.

Effect of Supplementary Methionine on Feather Growth and Related Indicators of Pigeon Squabs

ABSTRACT We assessed the effect of health sand dietary supplementation with methionine (Met) on White King pigeons. Paired pigeons (n = 180) were fed one of five diets; group T1 received no added Met, while T2, T3, T4 and T5 received 30, 60, 90 and 120 g of supplemental DL-Met/kg, respectively. Each treatment was replicated three times with 24 pairs in each replicate. The results showed that supplementary Met had a minor effect on the length of the fourth primary wing feather in 28-day-old squabs (p>0.05), but the length of 14-day-old squabs in T2 was significantly longer (p=0.010). Dietary Met had a minor effect on Wnt-7a and fibroblast growth factor receptors-2 (FGFR-2) mRNA levels in 28-day-old squabs (p>0.05). The IGF-1 concentration in plasma was highest in T4 and lowest in T2 (p=0.012), but there was no difference between T1, T2 and T5 (p>0.05). In the chest muscle, the expression of IGF-1 in T3 and T4 was higher than in T1 (p=0.172 and 0.015, respectively). In the leg muscle, IGF-1 mRNA level was higher in T4 and T3, and lower in T2 (p>0.05). The results indicate that the optimal Met supplement for increasing fourth primary wing feather length was 30 g/kg Met in health sand, and the feathers were the longest in 14-day-old squabs. Adding 90 g/kg Met to health sand can improve the concentration of IGF-1, which is important for growth performance of pigeon squabs.

Age-specific differences in wing pointedness and wing length of European Turtle Doves Streptopelia turtur migrating through the eastern flyway

ABSTRACT Migration plays a significant part in shaping wing morphology in avian taxa. Differences in wing shape and size have been found to vary with regard to age and sex, as well as between different populations. Here, we examine age-related variation in the wing morphology of the European Turtle Dove Streptopelia turtur migrating through the eastern flyway. Wing morphology was examined by means of a size-constrained components analysis (SCCA) of standardised primary-feather lengths of 112 individuals killed by hunters. Our results showed that juvenile individuals had shorter and more pointed wings than adults, which is consistent with the pattern observed in individuals migrating through the western flyway. We conclude that in juveniles, the selection force of migration is perhaps stronger than selection of an anti-predator adaptation. Moreover, age-related variation in Turtle Dove wing morphology may influence juvenile survival, as well as migration timing, and both effects should be considered in future studies.

Effects of L-methionine on growth performance, carcass quality, feather traits, and small intestinal morphology of Pekin ducks compared with conventional DL-methionine

The research studied the effects ofl-methionine (l-Met) on growth performance, carcass quality, feather traits, and small intestinal morphology of Pekin ducks compared with conventionaldl-methionine (dl-Met). A total of 1080, 1-day-old male Pekin ducks were randomly allotted to 9 groups with 6 replicate pens of 20 birds each. During the starter phase (1 to 14 d), ducks were fed a basal diet (Met, 0.30%) or that supplemented with dl-Met or l-Met at 0.05, 0.10, 0.15, or 0.20% of feed. During the grower phase (15 to 35 d), ducks were fed a basal diet (Met, 0.24%) or that supplemented with dl- Met or l-Met at 0.04, 0.08, 0.12, or 0.16% of feed. Compared with ducks fed the basal diet, supplementation with either dl- Met or l-Met increased the body weight (BW) of ducks at days 14 and 35, increased average daily gain (ADG) and average daily feed intake (ADFI), decreased F:G at the starter phase, and increased ADG over the whole 35-d period (P < 0.05). The efficacy of l-Met compared to dl- Met was 140.1% for 14-d BW, 137.6% for ADG and 121.0% for F:G for days 1 to 14. Ducks fed diets supplemented with l-Met had greater proportion of leg muscle, higher than in ducks provided with dl- Met (P < 0.05). The breast muscle proportion was enhanced with dl- Met rather than l- Met supplementation (P < 0.01). The back feathers score and fourth primary wing feather length were increased with dl- Met or l-Met supplementation (P < 0.01), and there was increased efficacy of l-Met relative to dl- Met for back feathers score (153.1%). Dietary dl- Met or l- Met supplementation increased villus height of ileal mucosa of ducks at days 14 and 35 (P < 0.01). Overall, dietary l-Met or dl- Met supplementation affected the growth performance of ducks during the starter phase, and improved the feather traits and small intestinal morphology. The efficacy of l-Met to dl- Met ranged from 120 to 140% for growth performance of young ducks (1 to 14 d) and was 153% for the feather traits of ducks (35 d).

Effects of stocking density on growth performance, feather growth, intestinal development, and serum parameters of geese

This experiment was conducted to evaluate the effects of stocking density on the growth performance, feather growth, intestinal development, and serum parameters of geese. In total, 336 healthy, 28-day-old, male Yangzhou goslings were randomly allotted to 30 plastic wire-floor pens according to 5 stocking densities (2, 3, 4, 5 and 6 birds/m2). The results showed that with the stocking density increased from 2 birds/m2 to 6 birds/m2, the body weights of geese at 42 d (P < 0.001) and 70 d (P < 0.001) were reduced by 10.53% and 10.43% respectively, the primary feather lengths of geese at 42 d (P < 0.001) and 70 d (P = 0.021) were reduced by 20.38% and 6.62% respectively, whereas the feed/gain ratios for 28- to 42-d period and 28- to 70-d period increased from 2.50 to 2.90 (P = 0.001), and 3.80 to 4.24 (P < 0.001), respectively. The relative weights of the jejunum, ileum, and small intestine and the lengths of the jejunum, ileum, and small intestine were all adversely affected (P < 0.05) when stocking density was increased to 6 birds/m2. Serum concentrations of alkaline phosphatase (P = 0.013) and triiodothyronine (P < 0.001) decreased as the stocking density increased. The serum thyroxine concentration of geese from the 6 birds/m2 group was lower than that of geese from the other groups (P < 0.05). The reduction in thyroid hormone concentrations was similar to what was observed in growth rate. All the results suggested that high stocking density will adversely influence thyroid function and the developments of the body weight, body size, feathers, and small intestine. Under our experimental conditions, we recommend that the stocking density of geese should be kept to 5 or fewer birds/m2 to avoid the negative effects of high stocking density on geese.

Influence of dietary rapeseed meal levels on growth performance, organ health and standardized ileal amino acid digestibility in meat ducks from 15 to 35days of age.

This study was conducted to investigate the effects of dietary rapeseed meal (RSM) inclusion levels on growth performance, organ health and standardized ileal amino acid digestibility (SIAAD) in meat ducks from 15 to 35days of age. Six hundred and eighty 15-days-old ducks were randomly allotted to five treatments based on body weight. Five isonitrogenous and isoenergetic diets were formulated on a digestible amino acid basis by replacing 0% (the control), 25%, 50%, 75% and 100% (based on fresh) of protein from soya bean meal (SBM) with protein from RSM. The corresponding levels of RSM in experimental diets were 0%, 6.66%, 13.32%, 19.98% and 26.64% respectively. With increasing dietary RSM levels, body weight (BW) and average daily gain (ADG) linearly decreased (p<0.001), whereas feed-to-gain ratio (F: G) linearly increased (p=0.0078). Ducks fed the diets with 13.32% or more RSM had significantly lower (p<0.05) BW, ADG and ADFI, or higher F: G than ducks fed the control diet. The maximum limit of dietary RSM supplementation was estimated to range from 4.27% to maximize ADG for 15 to 35days to 11.69% to maintain feed intake for 15 to 35days on the basis of a broken-line model. At day35, the 4th primary wing feather length and SIAAD (except for Met, Thr and Val) linearly decreased (p<0.001), and the thyroid glands weight (% of BW) linearly increased (p<0.05) with increasing dietary RSM levels. Ducks fed the RSM inclusion diets had significantly lower (p<0.0001) serum aspartate aminotransferase (AST) and alanine transaminase (ALT) activities than ducks fed the control diet. These results suggested that the maximum limit of dietary RSM containing 7.57μmol/g glucosinolates was estimated to be 4.27% to avoid growth reduction.

Evolutionary potential of morphological traits across different life-history stages.

Despite accumulating examples of selection acting on heritable traits in the wild, predicted evolutionary responses are often different from observed phenotypic trends. Various explanations have been suggested for these mismatches. These include within-individual changes across lifespan that can create important variation in genetic architecture of traits and selection acting on them, but also potential problems with the methodological approach used to predict evolutionary responses of traits. Here, we used an 8-year data set on tree swallow (Tachycineta bicolor) to first assess the effects of differences among three nestling life-history stages on the genetic (co)variances of two morphological traits (body mass and primary feather length) and the selection acting on them over three generations. We then estimated the evolutionary potential of these traits by predicting their evolutionary responses using the breeder's equationand the secondary theorem of selection approaches. Our results showed variation in strength and direction of selection and slight changes in trait variance across ages. Predicted evolutionary responses differed importantly between both approaches for half of the trait-age combinations we studied, suggesting the presence of environmentally induced correlations between focal traits and fitness possibly biasing breeder's equationpredictions. Our results emphasize that predictions of evolutionary potential for morphological traits are likely to be highly variable, both in strength and direction, depending on the life stage and method used, thus mitigating our capacity to predict adaptation and persistence of wild populations.

Relationship between developmental modes, flight styles, and wing morphology in birds

The aim of this work is to estimate the relationship between developmental mode and flight style, body mass and wing morphology of birds. We revealed high evolutionary correlation between developmental mode and flight style of birds. Different developmental modes, as well as flight styles, repeatedly appeared in birds’ evolution. Precocial birds are associated with continuous-flapping flight. Small altricial birds mostly use passerine-type flight. Soaring birds are large and have an intermediate developmental mode. Developmental strategies and flight styles correlate with differences in body mass and traits of wing morphology (wingspan, wing area, humerus, ulna, manus, and primary feather lengths). Nevertheless, by comparing results of phylogenetic and standard discriminant function analyses, we reveal that phylogeny strongly affects the morphology of wing traits and body mass in birds. When using phylogenetic t-tests, we did not find an association between relative length of wing elements and different developmental mode and flight style groups, except altricial birds with flapping and gliding flight style (Apodidae, Hirundinidae).

Genetic selection to increase bone strength affects prevalence of keel bone damage and egg parameters in commercially housed laying hens

The prevalence of keel bone damage as well as external egg parameters of 2 pure lines divergently selected for high (H) and low (L) bone strength were investigated in 2 aviary systems under commercial conditions. A standard LSL hybrid was used as a reference group. Birds were kept mixed per genetic line (77 hens of the H and L line and 201 or 206 hens of the LSL line, respectively, per pen) in 8 pens of 2 aviary systems differing in design. Keel bone status and body mass of 20 focal hens per line and pen were assessed at 17, 18, 23, 30, 36, 43, 52, and 63 wk of age. External egg parameters (i.e., egg mass, eggshell breaking strength, thickness, and mass) were measured using 10 eggs per line at both 38 and 57 wk of age. Body parameters (i.e. tarsus and third primary wing feather length to calculate index of wing loading) were recorded at 38 wk of age and mortality per genetic line throughout the laying cycle. Bone mineral density (BMD) of 15 keel bones per genetic line was measured after slaughter to confirm assignment of the experimental lines. We found a greater BMD in the H compared with the L and LSL lines. Fewer keel bone fractures and deviations, a poorer external egg quality, as well as a lower index of wing loading were found in the H compared with the L line. Mortality was lower and production parameters (e.g., laying performance) were higher in the LSL line compared with the 2 experimental lines. Aviary design affected prevalence of keel bone damage, body mass, and mortality. We conclude that selection of specific bone traits associated with bone strength as well as the related differences in body morphology (i.e., lower index of wing loading) have potential to reduce keel bone damage in commercial settings. Also, the housing environment (i.e., aviary design) may have additive effects.

Effect of dietary methionine content on growth performance, carcass traits, and feather growth of Pekin duck from 15 to 35 days of age

A study was conducted to establish the response of Pekin ducks to dietary Met from 15 to 35 d age. Experimental diets were formulated to contain 0.35, 0.45, 0.55, 0.65, and 0.75% Met (0.30, 0.39, 0.45, 0.56, and 0.68% on an analyzed basis, respectively) and 0.3% cysteine (0.25, 0.27, 0.26, 0.26, and 0.28% on an analyzed basis, respectively). Each diet was fed to 10 pens of 55 ducks/pen. Carcass yields and feather growth were determined at 28 and 35 d. Results showed that feeding 0.30% Met (0.55% Met+Cys) significantly impaired ADG, feed-to-gain (F:G) ratio, breast meat yield, and feather growth in comparison to the other dietary treatments (P < 0.05). BW, ADG, F:G, carcass and breast meat weight and yield, breast skin and subcutaneous fat weight and yield, the fourth primary wing feather length, and feather coverage showed significant quadratic broken-line or quadratic polynomial response to increasing dietary Met (P < 0.05). From 15 to 28 d age, the optimal Met requirement for the BW, breast meat yield, and the fourth primary wing feather length were 0.510, 0.445, and 0.404%, respectively, based on quadratic broken-line model, and correspondingly were 0.606, 0.576, and 0.559% by quadratic regression. For ducks from 15 to 35 d age, the optimal Met requirement for BW, breast meat yield, and feather coverage were 0.468, 0.408, and 0.484%, respectively, by quadratic broken-line model, and 0.605, 0.564, and 0.612%, by quadratic regression, respectively.

Change in wing morphology of the European starling during and after colonization of North America

AbstractWhen exposed to a new area and the potential for range expansion, species may quickly evolve morphological traits that allow them to colonize novel habitat. How quickly these changes occur and how long they subsequently persist in the established population has rarely been documented in birds. The European starling has been introduced in a number of areas around the world, including North America where an initially small population was established in 1890 and 1891. Their prolific expansion westward across the continent occurred at a tremendous rate of up to 90 km/year. We hypothesized that the individuals leading the expansion wave had longer and pointier wings because these characteristics are associated with greater juvenile dispersal distances. Therefore, we predicted that successive generations of range expanding birds would display increasing wing length and pointedness. Using museum specimens collected in North America since their introduction, we tested this hypothesis and examined temporal patterns to determine if wing shape changed following the establishment of local populations after the initial colonizing phase. Contrary to our expectations, wing length and shape did not change during the colonization wave. However, the pointedness of European starling wings decreased across the continent by more than 3.8% over the last 120 years. This was caused by an increase in the length of the secondary feathers, not by a decrease in the length of primary feathers. We discuss these results in the context of increased afforestation and urbanization during that time, and the potential benefit of rounder wings for foraging and predator avoidance.

Seasonal variation in the diet of Spoonbill chicks in the Wadden Sea: a stable isotopes approach

We used stable isotope tracers in the growing primary feathers of Eurasian Spoonbill chicks (Platalea leucorodia leucorodia) to study seasonal variation in their diet on one of the Frisian islands, Schiermonnikoog, The Netherlands. Using growing individual primaries as natural samplers over time, samples were taken along the length of primary feathers to estimate both within- and between-individual variation in diet. Absolute isotopic ratios of feather material ranged from −26.2 to −14.7 ‰ for carbon (δ13C) and from 13.0 to 18.7 ‰ for nitrogen (δ15N). The variation in δ13C values suggests the use of a variety of feeding habitats, ranging from freshwater to marine. Across the breeding season, there was a shift from predominantly freshwater prey early on to a more marine diet later in the season. Surprisingly, this shift did not occur within the growth trajectory of early born chicks which instead showed the opposite, but it did occur within individual chicks born later in the season. Stable isotope Bayesian mixing-model (SIAR) outcomes demonstrated that the freshwater/brackish prey had the highest isotopic contribution “(51 %; 95 % confidence interval 39–63 %) to the diet early in the breeding season, whereas marine prey contributed most (78 %; 66–89 %) to the diet later. That chicks fed with either freshwater or marine food items had similar body condition indices suggests that the eating of marine prey did not come at a major cost for growing Spoonbill chicks.

Age and Sex Differences in Fuel Load and Biometrics of Aquatic WarblersAcrocephalus paludicolaat an Autumn Stopover Site in the Loire Estuary (NW France)

The aquatic warbler Acrocephalus paludicola is the only globally threatened passerine breeding in Europe. We studied morphometric traits of 176 individuals captured at one of the key European autumn stopover sites, the Loire estuary on the Atlantic coast of France, in relation to age (first-year and older) and sex (based on molecular determination). We found significant sex differences in wing length, third primary feather length and body mass, with males being longer-winged and heavier than females; adult females also had deeper bills. However, high overlap in all measurements between the sexes meant the best discriminant functions based on wing length and bill depth (adults) and wing length (inmatures) correctly classified only 87% and 75% of individuals, respectively. The mean potential non-stop flight range of autumn staging birds at the Loire estuary with high fuel load was estimated at 1,178 km for adults and 926 km for immatures. We conclude that in autumn migrant aquatic warblers probably do not fly directly to wintering grounds in west Africa. Instead they gain significant body mass for onward migration at a few key stopover sites in western Europe and the southern Mediterranean region. Conservation of a series of important refuelling stopover sites, especially wet grassland habitats, along the migration route is therefore essential for effective protection of the aquatic warbler.

Primary feather lengths may not be important for inferring the flight styles of Mesozoic birds

Although many Mesozoic fossil birds have been found with primary feathers preserved, these structures have rarely been included in morphometric analyses. This is surprising because the flight feathers of modern birds can contribute approximately 50% of the total wing length, and so it would be assumed that their inclusion or exclusion would modify functional interpretations. Here we show, contrary to earlier work, that this may not be the case. Using forelimb measurements and primary feather lengths from Mesozoic birds, we constructed morphospaces for different clades, which we then compared with morphospaces constructed for extant taxa classified according to flight mode. Consistent with older work, our results indicate that among extant birds some functional flight groups can be distinguished on the basis of their body sizes and that variation in the relative proportions of the wing elements is conservative. Mesozoic birds, on the other hand, show variable proportions of wing bones, with primary feather length contribution to the wing reduced in the earlier diverging groups. We show that the diverse Mesozoic avian clade Enantiornithes overlaps substantially with extant taxa in both size and limb element proportions, confirming previous morphometric results based on skeletal elements alone. However, these measurements cannot be used to distinguish flight modes in extant birds, and so cannot be used to infer flight mode in fossil forms. Our analyses suggest that more data from fossil birds, combined with accurate functional determination of the flight styles of living forms is required if we are to be able to predict the flight modes of extinct birds