Molting Period Research Articles

Using stable isotopes to link breeding population trends to winter ecology in Willow Warblers, Phylloscopus trochilus

Capsule Stable isotope composition of feathers grown in Africa indicates that Willow Warblers, Phylloscopus trochilus, breeding in areas of Britain experiencing different population trends may vary in their distribution, timing of moult and/or use of prey resources during the non-breeding season. Aims To compare stable isotope ratios of feathers of Willow Warblers breeding in parts of Britain with differing rates of population change. Methods Feathers were collected from three regions with differing recent population trends; northern Scotland (population increased), western Wales (declined slightly) and eastern England (declined rapidly). Collection occurred at ringing sites run by British Trust for Ornithology (BTO) volunteers as part of the Constant Effort Sites (CES) scheme between April and July in 2008 and 2009. Results Willow Warblers from northern Scotland had significantly higher δ 15N and δ 13C values than those from eastern England, although the regional mean values did not differ greatly. There was no significant difference in δ 15N and δ 13C values between the sexes, but δ 15N values were significantly greater in individuals caught later in the breeding season. Conclusions During the premigratory moult period in Africa, Willow Warblers from different parts of Britain may vary in their distribution, timing of moult and/or use of prey resources.

Moulting phenology of the harbour seal in south-west Ireland

Studies on the phenology of harbour seal moult have been carried out in the Atlantic and Pacific, however there has been no research into this process in the Republic of Ireland, at the southern edge of the species range in the north-east Atlantic. Population estimates of harbour seals are derived by counts primarily during the moulting seasons. In the absence of information on the moult phenology planning the optimal timing of such surveys is impossible. Furthermore, changes in moult phenology may reflect changes in resource availability or competition, or demographic changes. The phenology of the harbour seal moult was investigated in south-west Ireland in this study. Timing of the moult differed among all cohorts, yearlings began moulting first followed by adult females and finally adult males. The number of seals hauled out was generally positively related to the proportion of seals in active moult. The timing of the moult period was different to other parts of the species' range and should be considered in determining optimal timing of future surveys for assessing populations abundance and trends in Ireland.

Feathers as a Biomonitoring Tool of Polyhalogenated Compounds: A Review.

Feathers have many advantages that make them an excellent nondestructive tool for monitoring polyhalogenated compounds (PHCs). This paper proposes a review on the PHCs in feathers and factors influencing the pollutant load. Special attention has given to external contamination and the main analytical methods used to detect these compounds in feathers. Some authors have found strong and significant correlations between the concentrations of PHCs in feathers and internal tissues, providing positive expectations for their future use in the field of ecotoxicology. However, changes in diet, time elapsed between the previous molt period and sampling, sample size, and/or external contamination have been suggested as possible causes to explain the lack of correlations reported in some studies. Further studies with newly grown feathers and blood samples would be required in order to clarify this issue. Although atmospheric deposition has been reported as cause of external contamination, preening oil seems to be the most relevant factor contributing to this process. Unfortunately, washing techniques tested to date are not able to effectively remove the surface contamination from barbs and shafts, and therefore, it is necessary to develop methods able to discriminate between internal and external contamination. Finally, in this review, deposition rate is proposed as a measurement unit, as this allows comparisons between different parts of the same feather, as well as between different feathers.

Effects of Hen Age and Force Molting Programs on Body Weight Loss and Heterophil: Lymphocyte Ratio during Molt Period in Laying Hens

The aim of this study was to determine the effects of hen age and force molting programs on body weight loss, egg production cease and heterophil:lymphocyte ratio during molt period. The experiment was conducted using 320 Hy-Line W36 hens randomly assigned to experimental groups (five replicates of 8 hens for each treatment). The experimental design of the study was a 2 × 4 factorial arrangement of a completely randomized design. Eight treatments were compared in a 2 x 4 factorial arrangement with 2 age treatment (63 and 75 week of age) and 4 force molting treatments [feed withdrawal (FW), 100% alfalfa (A), 50% alfalfa and 50%oat (AO), and 100% oat (O)]). The hen age had no significant effect on BW loss, cease egg production and H: L ratio during molt period. The FW had significantly (P<0.01) higher BW loss than AO and O treatments and it was similar to A treatment. Egg production for all treatments ceased completely by day 6. H: L ratio were significantly higher for FW treatment when compared with nonfeed withdrawal treatments. The results indicated that alfalfa or oat appears to be alternatives to FW methods for force molting.

Growth per Molt of Snow Crab in the Eastern Bering Sea

AbstractThe growth per molt of snow crab Chionoecetes opilio in the eastern Bering Sea is poorly known, primarily because snow crabs are difficult to sample during their spring molting period due to the presence of sea ice. To provide better estimates of growth per molt for the stock assessment model used to manage the snow crab fishery, a study was conducted to collect juvenile crabs with a bottom trawler and return them to holding facilities at Dutch Harbor and Kodiak, Alaska. Since relatively few of these crabs subsequently molted, these data were augmented with molting data collected by two previous, unpublished studies. Based on a total of 35 observations, snow crabs grew according to the following premolt (PRMW) and postmolt (POMW) carapace width relationships: POMW = −4.00 + 1.46(PRMW), where PRMW &lt; 36.1 mm, and POMW = 48.83 + 1.17(PRMW − 36.1), where PRMW ≥ 36.1 mm.Received July 23, 2012; accepted September 13, 2012

Revisiting reproduction and population structure and dynamics ofProcambarus clarkiieight years after its introduction into Lake Trasimeno (Central Italy)

Key-words: red swamp crayfish, Procambarus clarkii, reproduction, population structure and population dynamics, invasive species Understanding population dynamics and regulation is fundamental for predicting establishment and spread of invasive alien species. In addition, the population biology of invasive alien species offers an opportunity to study basic ecological processes. In this context, we investigated reproductive and growth plasticity in the invasive crayfish Procambarus clarkii in Lake Trasimeno (central Italy). In total, 3153 crayfish were collected monthly from June 2007 to July 2009. The molt status was assessed by evaluating the exoskeleton hardness. To assess the reproductive cycle, the gonado-somatic and wet hepato-somatic indices were calculated for females. The reproductive status of males was appraised as well. We estimated growth and longevity using the von Bertalanffy growth function, and calculated the total, natural and fishing mortality indices. We then compared our present data with those obtained from the same population eight years before. Our results indicate some changes in population dynamics and in both molting and reproductive periods since the initial invasion of the shallow lake investigated. Long-term differences in the life history of the Trasimeno population may be the result of selective pressures different from those of the native range, but may also result from colonization events and human interference caused by professional fishing activities.

Seasons of the ringed seal: pelagic open-water hyperphagy, benthic feeding over winter and spring fasting during molt

Context The ringed seal (Phoca hispida), a small phocid seal with a circumpolar Arctic distribution and a strong association with sea ice, occurs at the southern limit of its range in Hudson and James Bays: an area that experiences complete ice cover in winter and complete open water in summer. Because of the high seasonal variability in environmental conditions, it is expected that ringed seals experience seasonal changes in diet and foraging habitat, which will be reflected in body condition and biomarkers of stable isotopes and fatty acids. Aims The purpose of the present study was to investigate intra-annual variation in the feeding habits and body condition of the ringed seal. Methods Tissue samples and morphological measurements from south-eastern Hudson Bay ringed seals were obtained every month during the Inuit subsistence hunt from November 2009 to May 2011 (n = 192). Muscle samples were used for δ15N and δ13C stable isotope analysis, blubber was used for analysis of fatty acid composition, bodyweight and sculp weight were used to estimate percentage blubber, and lower right canines were used to determine age. Key results Fatty acid composition, δ15N, and δ13C varied significantly by season, suggesting seasonal changes in foraging habitat and diet. Variation in percentage blubber indicated that poorest body condition occurs following the molting and fasting period, followed by a gradual increase from late summer through fall, with the highest body condition occurring in time for freeze-up in December. Key conclusions Patterns of δ13C indicate pelagic feeding during the open-water season (August–December) when fat and energy stores are replenished, increased benthic foraging during the period of ice cover (January–May), followed by a period of fasting during the spring molt (June–July). Fatty acid composition suggested seasonal changes in diet that could include increased importance of pelagic fish in the fall during the period of positive energy balance. Implications The first continuous collection of ringed seal tissue samples provided a comprehensive seasonal pattern of biomarker composition, which is baseline data that have important applications for short-term management and ecology studies as well as long-term conservation and monitoring programs.

室内养殖雌性松鼠秋季换毛期被毛长度和保温性能变化

Pelage is one of the most important characteristics of mammals.The research about the association between molting and environment is an important aspect in the study of animal ecology.Mammals′ autumn molting is completely to taking off their summer hairs and growing rich hairs in winter.But the quantitative studies of thermal insulation of animals′ pelage which was changing in the autumn molting process have not been involved.Our objective was to find out the relationship between characteristics and heat insulation of hair in squirrel,Sciurus vulgaris manchuricus,that is molting in autumn.In order to study the association between hair length and pelage thermal insulation property,we measured hair length and tested thermal insulation of skins of 27 female squirrels(Sciurus vulgaris manchuricus)(twenty-five adults and two subadults) during autumn molting period.The hairs(5 intermediate guard hairs and 5 undercoat hairs) were sampled from the mid back of each skin and thermal insulation was tested at the same site.Results showed that 1) with the progression of autumn molting,the pelage thermal conductivity decreased in association with increment of winter hair length,and reached stable at the end of hair growth.2) Significant positive associations were detected between pairs of four hair indexes namely the length of intermediate guard hairs,length of under hairs,root of medulla-absent proportion in intermediate guard hairs and under hairs(P0.01).Meanwhile,these four indexes were also significantly negatively associated with thermal conductivity coefficient(P0.01).These results suggest pelage thermal conductivity is effected by the thickness of under fur.In conclusion,the results reflect the specific changes and interrelation of hair length,the extent of growth and thermal insulation in the every time stage during autumn molting period.

Construction of biological reference points for management of the Dungeness crab, Cancer magister, fishery in the Fraser River Delta, British Columbia, Canada

The objective of this study was to define two biological reference points, the Upper Stock Reference Point (USR) and the Limit Reference Point (LRP), to facilitate management of the Fraser River delta commercial Dungeness crab (Cancer magister) fishery in a precautionary manner. The USR is the stock level below which the removal rate is progressively reduced to avoid reaching the LRP. The LRP is the stock level below which productivity is sufficiently impaired to cause serious harm. Currently, the commercial Dungeness crab fishery in the Fraser River delta is managed with a minimum size limit (165mm carapace width point-to-point), non-retention of females and soft-shell crabs, and a restricted fishing season (June to November) to protect large males during the winter/spring moult period. We evaluated variations in legal male, sublegal male, and female Dungeness crab abundances using fishery-independent trap surveys from 1988 to 2010. We also examined proportions of soft-shell legal male and female crabs using survey data and information collected from commercial fishing. A relationship existed between female abundance and corresponding legal male abundance five years later, which is well described by the Beverton–Holt stock–recruitment model. We conducted simulations to assess possible adverse impacts of fishing on the crab population. We assumed the population would stabilize at the existing abundance upon suspension of commercial harvesting if abundance has been steadily declining. Using the stock–recruitment relationship along with information on commercial catch compositions and soft-shell proportions, we assessed the potential reduction in legal male and female crab abundances, given persistent fishing, before the population reaches a lower equilibrium. The amount of reduction to legal male and female crabs increases with decreasing population size. If legal male crab abundance is 50% and 20% of maximum possible recruitment, then fishing would reduce female abundance by 20% and 48%, respectively, before the population is stabilized. We propose these two female abundance levels as the USR and LRP for managing the Fraser River commercial Dungeness crab fishery.

Life cycle and behavior of Amblyomma rotundatum (Acari: Ixodidae) under laboratory conditions and remarks on parasitism of toads in Brazil

The life cycle and behavior of Amblyomma rotundatum were evaluated under laboratory conditions. The experiment started with four engorged females collected from toads (Rhinella schneideri) naturally infested at the Pirapitinga Ecological Station in the state of Minas Gerais, Brazil. Developmental periods of free-living stages were assessed in an incubator at 27±1°C, >80 % RH and darkness. The complete life cycle, including pre-attachment periods for each parasitic stage, ranged from 126 to 228days. The pre-attachment, feeding and molting periods increased as the life cycle progressed from larva to adult female. Oviposition lasted about 20days, with the peak occurring on days 4 and 5. Longevity of nymphs and adult females was quite similar (approximately 250 and 240days, respectively) and slightly longer than that of larvae. Lesions caused by tick feeding are discussed and a list of known hosts, including new host records for A. rotundatum, is offered.

RELATIONSHIP BETWEEN PROLACTIN HORMONE LEVEL, MOLTING AND DUCK EGG PRODUCTION

The aims of this study were to obtain information on the mechanism of molting and the prolactinhormone levels affecting egg production. The study utilized AP (crossbred of Alabio ♂ with Peking ♀)and PA (crossbred of Peking ♂ and Alabio ♀ ducks) with a total of 180 birds. The observed variableswere the duration of cessation of egg production before and after molting, the prolactin hormone level inthe period of molting, the egg production period before and after molting. The data was analyzed usingANOVA, regression and correlation. The results showed that AP crossbred had fewer molting (23.33%)compared to PA (50.00%). The mechanism of molting is always preceded by cessation of eggproduction, molting and relaying. The prolactin hormone concentrations of AP and PA in the periodbefore and after molting were significantly higher than in the period of molting. At the egg productionperiod before molting, the prolactin hormone concentration of AP ducks was higher than the PA ducks.So that the egg production of AP before molting (0-16 weeks) was higher than the PA. The eggproduction of AP was higher than PA, 256.66±6.00 vs 232.22±6.64 eggs for 48 weeks. So it can beconcluded that the prolactin hormone affects the molting and egg production.

Extending an indicator: year-round information on seabird trophic ecology from multiple-tissue stable-isotope analyses

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 461:233-243 (2012) - DOI: https://doi.org/10.3354/meps09835 Extending an indicator: year-round information on seabird trophic ecology from multiple-tissue stable-isotope analyses Keith A. Hobson1,*, Alexander L. Bond1,2 1Environment Canada, 11 Innovation Blvd., Saskatoon, Saskatchewan S7N 3H5, Canada 2Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada *Email: keith.hobson@ec.gc.ca ABSTRACT: Stable isotope analysis of tissues of seabirds and their prey has proven to be an extremely useful tool in seabird dietary studies in general and in the potential use of seabirds as ecological indicators in particular. The measurement of stable carbon (δ13C) and nitrogen (δ15N) isotope values is important since they provide information on source of feeding and trophic position, respectively. However, the stable isotope approach provides information on spatial and trophic ecology of seabirds during a window of temporal integration that depends on the elemental turnover rate in the tissue being measured. Most researchers have relied on only 1 or 2 tissue types to study seabird diets and foraging ecology. Here, the potential for modeling trophic position and habitat use by seabirds over the annual cycle is demonstrated by using multiple tissues from the same individual. Isotopic measurements of bone collagen provide information integrated over the lifetime of the individual and those of feathers during the post-breeding molt period. Analysis of liver provides information integrated over the previous week and that of muscle integrated over a few months. We developed multi-tissue trophic models for thick-billed murre Uria lomvia, dovekie Alle alle, black guillemot Cepphus grylle, glaucous gull Larus hyperboreus, northern fulmar Fulmarus glacialis, black-legged kittiwake Rissa tridactyla, and ivory gull Pagophila eburnea using the Northwater Polynya in Northern Baffin Bay, 1998 to 1999. The careful application of stable isotope methods to a spectrum of tissue types represents a powerful means of extending our ability to investigate diet and potentially to use seabirds as ecological indicators. KEY WORDS: Stable isotopes · Carbon-13 · Nitrogen-15 · Seabirds · Temporal integration Full text in pdf format PreviousNextCite this article as: Hobson KA, Bond AL (2012) Extending an indicator: year-round information on seabird trophic ecology from multiple-tissue stable-isotope analyses. Mar Ecol Prog Ser 461:233-243. https://doi.org/10.3354/meps09835 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 461. Online publication date: August 08, 2012 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2012 Inter-Research.

DNA replication events during larval silk gland development in the silkworm, Bombyx mori

The silk gland is an important organ in silkworm as it synthesizes silk proteins and is critical to spinning. The genomic DNA content of silk gland cells dramatically increases 200–400 thousand times for the larval life span through the process of endomitosis. Using in vitro culture, DNA synthesis was measured using BrdU labeling during the larval molt and intermolt periods. We found that the cell cycle of endomitosis was activated during the intermolt and was inhibited during the molt phase. The anterior silk gland, middle silk gland, and posterior silk gland cells asynchronously exit the endomitotic cycle after day 6 in 5th instar larvae, which correlated with the reduced expression of the cell cycle-related cdt1, pcna, cyclin E, cdk2 and cdk1 mRNAs in the wandering phase. Additional starvation had no effect on the initiation of silk gland DNA synthesis of the freshly ecdysed larvae.

Evidence of cryptic individual specialization in an opportunistic insectivorous bat

Habitat use and feeding behaviors of cryptic animals are often poorly understood. Analyses of stable isotope ratios in animal body tissues can help reveal an individual's location and resource use during tissue growth. We investigated variation in stable isotope ratios of 4 elements (H, C, N, and S) in the hair of a sedentary species of insectivorous bat (Eptesicus fuscus) inhabiting a chemically complex urban landscape. Our objective was to quantify population-level isotopic variation and test for evidence of resource specialization by individuals. Bats were sampled over 3 annual molt cycles at maternity roosts in buildings and variance components analysis was used to test whether intraindividual isotopic variation among molts differed from interindividual variation, after controlling for year and roost-group effects. Consistent with prior evidence that E. fuscus is opportunistic in its habitat use and foraging at the population level, we observed wide population-level variation for all isotopes. This variation likely reflects the chemical complexity of the urban landscape studied. However, isotopic variation among years within marked individuals was lower than variation among marked individuals within year for all isotopes, and carbon signatures indicated resource specialization by roost groups and individuals. This is the 1st study to examine variation in stable isotope ratios of individual wild bats over multiple years. Although our results suggest this population tends toward opportunistic habitat use or prey selection, or both, during molt periods, results also indicate that individuals and groups of bats composing the population might be habitat or dietarv specialists—a novel finding for insectivorous bats.

EFFECT OF FORCE MOLTING BY ZINC OXIDE AND THE ROLE OF VITAMIN C ON BODY WEIGHT AND REENTRY TO PRODUCTION OF BROILER BREEDER

A total of 296 Arbor Acres broiler breeder 375 days old were randomly divided into eight treatment. Hens in each treatment were subdivided into five replicates and reared on the floor throughout the experimental period. Two treatments free of Zinc included control with or without vitamin C; six treatments included three levels of Zn as ZnO (15000, 20000 and 25000ppm) with or without vitamin C. All treatments extirpated significant differences in percentage body weight loss during molting program. The most significant loss occurred in the T8 and T7 hens. The most reduction of feed intake (%) occurred in T8, T7 and T6 respectively. Furthermore, molting periods significantly affect body weight loss and feed intake (%). The most significant loss of body weight and reduction of feed intake (%) were occurred at day 9 of molting period. Moreover, T4 hens significantly take up more days to 1st day out of production, less days to out of production and to return to egg production compared with other molting treatments

The phenology of molting, breeding and their overlap in central Amazonian birds

The energetically challenging periods of molting and breeding are usually temporally separated in temperate birds, but can occur simultaneously in tropical birds, a condition known as molt–breeding overlap. Here, we document great variation in the timing and duration of molting and breeding, and in the extent of molt–breeding overlap, among 87 species of understory passerines in central Amazonia. We analyzed molt and breeding from 26 871 birds captured over a 30‐yr period near Manaus, Brazil. Although most species typically bred during the late dry season (about October through January), many thamnophilids apparently bred year‐round, whereas a few other species from a variety of families bred mainly during the wet season (about January through May). Of all breeding birds with an active brood patch, 12.7% were simultaneously molting. Molt–breeding overlap was more frequently observed among suboscines (13.3%), especially thamnophilids (23.0%), than oscines (6.4%). Some families had &lt;5% molt–breeding overlap frequency, including Tyrannidae (4.4%), Tityridae (0.0%), Pipridae (1.5%), Turdidae (0.0%), and Thraupidae (0.0%), indicating that not all tropical species exhibit molt–breeding overlap. Among 31 well‐sampled species (n ≥15 brood patches), variation in molt–breeding overlap frequency was positively correlated with each species’ average duration of flight feather replacement (range 98–301 d). We also measured feather growth rates of individual birds in nine species; in five of these, slower‐growing feathers increased with an individual's probability of having molt–breeding overlap. Among furnariids, molt–breeding overlap occurred either at the beginning or end of the molt cycle, suggesting that physiological mechanisms typically separate molting from breeding. Thamnophilids showed a much different pattern; molt–breeding overlap occurred at any stage of feather replacement, apparently not regulated to be independent of breeding. These results reveal substantial life‐history variation among Amazonian birds. Future work to resolve the physiological regulation of molting and breeding in tropical birds will greatly contribute to understanding these patterns and their relevance to avian diversity.

Evidence of Latitudinal Migration in Tri-colored Bats, Perimyotis subflavus

BackgroundAnnual movements of tri-colored bats (Perimyotis subflavus) are poorly understood. While this species has been considered a regional migrant, some evidence suggests that it may undertake annual latitudinal migrations, similar to other long distance North American migratory bat species.Methodology/Principal FindingsWe investigated migration in P. subflavus by conducting stable hydrogen isotope analyses of 184 museum specimen fur samples and comparing these results (δDfur) to published interpolated δD values of collection site growing season precipitation (δDprecip). Results suggest that the male molt period occurred between June 23 and October 16 and 33% of males collected during the presumed non-molt period were south of their location of fur growth. For the same time period, 16% of females were south of their location of fur growth and in general, had not travelled as far as migratory males. There were strong correlations between δDfur from the presumed molt period and both growing season δDprecip (males – r 2 = 0.86; p<0.01; females – r 2 = 0.75; p<0.01), and latitude of collection (males – r 2 = 0.85; p<0.01; females – r 2 = 0.73; p<0.01). Most migrants were collected at the northern (>40°N; males and females) and southern (<35°N; males only) extents of the species' range.Conclusions/SignificanceThese results indicate a different pattern of migration for this species than previously documented, suggesting that some P. subflavus engage in annual latitudinal migrations and that migratory tendency varies with latitude and between sexes. We suggest that this species' hibernation ecology makes it particularly susceptible to long winters, making migration from the northern extent of the species' range to more southern hibernacula preferable for some individuals. Fur δD values for some of the northern individuals may indicate an increase in the currently accepted northern range of this species. Sex-biased differences in migration may be the result of differences in reproductive pressures.

THE RESULTS OF MOLTING BEARING HENS

The swarm of Hy Line bearing hens (8260 pieces) held in three floor cages were molted at the age of 87 weeks. In the first producing season the swarm did not reach the planned weight and in 87 weeks the average weight of hens was 1768 grams. The reduced body weight caused a slightly smaller production than planned, so the production of eggs on each hen was 335 pieces, and the mass of the eggs on each hen was 20.9 kilos. The average daily meal was 133 grams. The swarm was healthy during the entire production period, and the deaths reached 4,8%. The owner of hens decided to molt when the average production per week was 57.56%, and the percentage of eggs with low quality reached 4.85%. The intense molting was conducted according to a plan of restricting food, water and light, made especially for this swarm. The plan was also adjusted during the production period, because of the low temperatures outside and inside the object where hens were held. Molting lasted for six weeks, hens lost 22% of body weight, and the period of the second egg bearing lasted two weeks. In the second producing season 93% of the eggs was in SS, S and A weight category. Eggs with soft shell were reduced to 0,8%, the amount of food spent per hen daily was 135 grams, during the six months long production, 170 eggs per hen were produced. Death during molting and production period in the second producing season was 6.4%.

The molt stages and the hepatopancreas contents of lipids, glycogen and selected inorganic elements during the molt cycle of the Chinese mitten crab Eriocheir sinensis

A rapid molt-staging technique was developed for the Chinese mitten crab Eriocheir sinensis, with the aim of investigating selected molt-linked biochemical and inorganic factors in these animals. The results allow the identification of four distinct molting periods (postmolt, intermolt, premolt and ecdysis) and the further classification of the premolt period into three substages (D0, D1 and D3-4). These findings are consistent with the classical scheme elaborated by Drach and Tchernigovtzeff (Vie Milieu 18:595–610, 1967). The contents of lipids, glycogen and several inorganic elements (Ca, Mg, Cu and Zn) in the hepatopancreas fluctuated and agreed well with their functions and with the molting stages during the molt cycle.

Variation in carbon and nitrogen stable isotope ratios in flight feathers of a moulting White-bellied Sunbird Cinnyris talatala

We measured δ13C and δ15N isotope signatures in flight feathers of a White-bellied Sunbird to assess the value of using stable isotopes of feathers in avian dietary studies. Significant variation in δ13C and δ15N isotope values of flight feathers (range = 3.1%o and 2.7%o, respectively) indicated that the source of carbon (i.e. C3 or CAM) and trophic level position shifted significantly during the flight feather moult period. Temporal dietary changes in an individual sunbird highlight the implications for interpreting avian diets using stable isotopes. However, by analysing feathers, dietary input may be interpreted at different levels if the moult process is well understood.