High-quality Birds Research Articles

Food supply and individual quality influence seabird energy expenditure and reproductive success.

Breeding animals trade off maximizing energy output to increase their number of offspring with conserving energy to ensure their own survival, leading to an energetic ceiling influenced by external, environmental factors or by internal, physiological factors. We examined whether internal or external factors limited energy expenditure by supplementally feeding breeding black-legged kittiwakes varying in individual quality, based on earlier work that defined late breeders as low-quality and early breeders as high-quality individuals. We tested whether energy expenditure increased when food availability decreased in both low- and high-quality birds; we predicted this would only occur in high-quality individuals capable of sustaining high levels of energy expenditure. Here, we find that food-supplemented birds expended less energy than control birds because they spent more time at the colony. However, foraging trips of food-supplemented birds were only slightly shorter than control birds, implying that food-supplemented birds were limited by food availability at sea similarly to control birds. Late breeders expended less energy, suggesting that low-quality individuals may not intake the energy necessary for sustaining high-energy output. Food-supplemented birds had more offspring than control birds, but offspring number did not influence energy expenditure, supporting the idea that the birds reached an energy ceiling. Males and lighter birds expended more energy, possibly compensating for relatively higher energy intake. Chick-rearing birds were working near their maximum, with highest levels of expenditure for early-laying (high-quality) individuals foraging at sea. Due to fluctuating marine environments, kittiwakes may be forced to change their foraging behaviors to maintain the balance between reproduction and survival.

Does the Urban Environment Act as a Filter on the Individual Quality of Birds?

Phenotypic divergences of birds are common between urban and natural habitats and can result from different selective pressures between habitats or maladaptation to the city. No uniform patterns were observed, especially concerning markers of bird health, such as, for example, telomere length. Telomeres are involved in maintaining genome integrity and naturally shorten with age, but environmental stressors can accelerate their attrition. Thus, telomere length can be an indicator of individual quality. Some studies showed that urban breeders had longer telomeres than forest individuals. Two hypotheses can explain this result: (1) urban breeders are younger than forests breeders, and (2) cities act as a filter on individuals and only high-quality birds can successfully reproduce. In this context, we compared the age category (molting pattern) and morphological and physiological characteristics of urban and forest Great Tits before and during breeding. No differences in age or body condition were observed. However, urban breeders were smaller and had shorter telomeres than birds captured in winter. Urban birds had longer telomeres than forest birds, only in winter. These results highlight that urban habitats potentially favor smaller birds. However, the decrease in telomere length between winter and reproduction only in the city suggest a higher cost of reproduction in the city compared to the forest.

The influence of processing of hatching eggs by coniferous complex on fetal and postnatal development of quails

The hatchery is an important link in the production process of a poultry enterprise, and therefore there is a need to take eff ective measures to prevent the penetration and spread of infection. For this purpose hatching eggs are processed, veterinary and sanitary measures are carried out using disinfectants. The most common chemical disinfectants, but many of them have a short-term eff ect and have a negative infl uence on the embryos, and the task of any incubator is to get high-quality young birds. In most cases poultry farms use formalin, which when used repeatedly has a negative enfl uence not only on the embryos and their development, but also on the maintenance staff . In this regard, the creation of non-toxic, highly eff ective, eco-friendly products that do not pollute the environment, inhibit the growth of microorganisms that do not aff ect the embryo and maintenance personnel is an urgent task for veterinary science and practice. One of these drugs is a complex of coniferous balsamic fi r. The purpose of our researches was to study the infl uence of treatment of hatching eggs with the new drug on the fetal and postnatal development of quails. Egg processing has been performed before laying and during transfer in 15,5 days: in the experimental group with coniferous complex, in the control group with formalin. Biological control has been carried out in 9,5 and 15,5 days, taking into account the hatchability of eggs, the livability and live weight of quails. Blood has been collected at the age of 7 and 14 days for biochemical analysis, examining it for the content of total protein, albumins and globulins. The complex coniferous balsamic fi r did not have the negative infl uence on the fetal and postnatal development of the resulting young birds increased the hatchability of eggs, the livability and live weight of quails. Thus, the live weight of quails in the experimental group at the age of 7 days exceeded the control by 2,3 %, and at 14 days by 0,3 %. The livability of quails obtained from eggs treated with the studied drug the period of 1–14 days was 2,0 % higher compared to the control group.

Inter-individual differences in the foraging behavior of breeding Adélie penguins are driven by individual quality and sex

Inter-individual differences in demographic traits of iteroparous species can arise through learning and maturation, as well as from permanent differences in individual ‘quality’ and sex-specific constraints. As the ability to acquire energy determines the resources an individual can allocate to reproduction and self-maintenance, foraging behavior is a key trait to study to better understand the mechanisms underlying these differences. So far, most seabird studies have focused on the effect of maturation and learning processes on foraging performance, while only a few have included measures of individual quality. Here, we investigated the effects of age, breeding experience, sex, and individual breeding quality on the foraging behavior and location of 83 known-age Adélie penguins at Cape Bird, Ross Sea, Antarctica. Over a 2 yr period, we showed that (1) high-quality birds dived deeper than lower quality ones, apparently catching a higher number of prey per dive and targeting different foraging locations; (2) females performed longer foraging trips and a higher number of dives compared to males; (3) there were no significant age-related differences in foraging behavior; and (4) breeding experience had a weak influence on foraging behavior. We suggest that high-quality individuals have higher physiological ability, enabling them to dive deeper and forage more effectively. Further inquiry should focus on determining the physiological differences among penguins of different quality.

Computer Generation of Birds of a Feather Puzzles

In this article, we describe a computer-aided design process for generating high-quality Birds of a Feather solitaire card puzzles. In each iteration, we generate puzzles via combinatorial optimization of an objective function. After solving and subjectively rating such puzzles, we compute objective puzzle features and regress our ratings onto such features to provide insight for objective function improvements. Through this iterative improvement process, we demonstrate the importance of the halfway solvability ratio in quality puzzle design. We relate our observations to recent work on tension in puzzle design, and suggest next steps for more efficient puzzle generation.

Distribution and breeding ecology of the Ferruginous Duck Aythya nyroca in Algeria

We conducted a survey of the distribution of Ferruginous Duck Aythya nyroca across Algeria and analysed the influence of nest-site characteristics on nesting success at a Ramsar site, Lake Tonga. The species was found to occupy different wetlands (freshwater lakes, brackish marshes and salt lakes) across three major climatic belts (subhumid coastal strip, semi-arid Hauts Plateaux and arid Sahara). Mean clutch size of successful nests was 13.3 ± 6.0 eggs (N = 26) with a hatching rate of 74% for successful clutches. Nesting success was recorded for 44% of nests with clutch desertion (72.7%) accounting for the majority of failed clutches. Egg size of the study population, which breeds at the southern limit of the species’ range, was significantly smaller than that of its northerly counterparts. Clutch size was negatively related to egg size and positively associated with depth of water below the nest, suggesting that older, more experienced or high-quality birds monopolised the safest sites. Successful clutches were significantly associated with tall vegetation, suggesting that when nesting is carried out mainly on offshore floating islets, protection against aerial predators and heat stress determine nesting outcome. Conspecific brood parasitism was significantly and positively associated with deferred egg-laying and smaller egg size, suggesting an age-dependent mechanism.

Individual quality via sensitivity to cysteine availability in a melanin-based honest signaling system.

The evolution of honest animal communication is mostly understood through the handicap principle, which is intrinsically dependent on the concept of individual quality: low-quality individuals are prevented from producing high-quality signals because, if they did so, they would pay greater production costs than high-quality individuals. We tested an alternative explanation for the black bib size of male house sparrows, Passer domesticus, an honest signal of quality the expression of which is negatively related to levels of the pigment pheomelanin in the constituent feathers. We previously showed that experimental depletion of cysteine, which participates in pheomelanogenesis, improves the phenotype (bibs larger than in controls) of high-quality males (birds with largest bibs initially) only. Here, we conducted an experiment under opposite conditions, increasing the availability of dietary cysteine, and obtained opposite results: deteriorated phenotypes (bibs smaller than in controls) were only expressed by high-quality birds. Some birds were also treated with the pro-oxidant diquat dibromide, and we found that the cellular resistance to free radicals of high-quality birds benefited more from the antioxidant activity of cysteine against diquat than that of low-quality birds. These findings support the existence of a mechanism uncoupling cysteine and pheomelanin in low-quality birds that confers on them a low sensitivity to variations in cysteine availability. This constitutes an explanation for the evolution of signal honesty that overcomes the limitations of the handicap principle, because it provides a specific definition of individual quality and because costs are no longer required to prevent low-quality individuals from producing large signals.

Phaeomelanin- and carotenoid-based pigmentation reflect oxidative status in two populations of the yellow warbler (Setophaga petechia)

Carotenoid- and phaeomelanin-based sexual pigmentation may signal a capacity to maintain oxidative balance and viability. However, diverse empirical results leave the association between pigmentation and oxidative stress (OS) unclear. We assessed the hypothesis that population-specific levels of oxidative challenge, or strategies for managing OS, affect relationships between sexual pigmentation and OS. Specifically, intense oxidative challenge in migratory, temperate breeding birds might enhance correlations between pigmentation and OS relative to allied tropical breeders, since quality-based differences in OS may arise only under intense oxidative challenge. Alternatively, in temperate breeders with intense within-season reproductive effort, high-quality birds may invest in reproduction over oxidative balance, dampening negative correlations between pigmentation and OS. To assess these alternatives, we compared prenesting relationships between pigmentation and OS in a migratory, Californian population of yellow warblers (Setophaga petechia brewsteri) and in a resident, Mexican population (Setophaga petechia bryanti, “mangrove warblers”). Yellow warblers displayed higher OS than mangrove warblers. However, year of capture and sex had bigger influences on correlations between pigmentation and OS than population. Males with more intense melanin pigmentation had lower OS among mangrove warblers and yellow warblers captured in 2011, but not among yellow warblers captured in 2012. In females only, lower OS levels were associated with more colorful carotenoid pigmentation. Results suggest that both phaeomelanin- and carotenoid-based pigmentation have the potential to correlate with OS levels, but that the signaling potential of pigmentation may shift with inter-annual variation in environmental conditions and display sex-specific dynamics.

Flight performance of western sandpipers Calidris mauri remains uncompromised when mounting an acute phase immune response

Migratory birds have been implicated in the spread of some zoonotic diseases, but how well infected individuals can fly remains poorly understood. We used western sandpipers, Calidris mauri, to experimentally test whether flight is affected when long-distance migrants are mounting an immune response and whether migrants maintain immune defences during a flight in a wind tunnel. We measured five indicators of innate immunity in 'flown-healthy' birds (flying in a wind tunnel without mounting an immune response), 'flown-sick' birds (flying while mounting an acute phase response, which is part of induced innate immunity), and a non-flying control group ('not-flown'). Voluntary flight duration did not differ between flown-healthy and flown-sick birds, indicating that mounting an acute phase response to simulated infection did not hamper an individual's ability to fly for up to 3 h. However, in comparison to not-flown birds, bacterial killing ability of plasma was significantly reduced after flight in flown-sick birds. In flown-healthy birds, voluntary flight duration was positively correlated with bacterial killing ability and baseline haptoglobin concentration of the blood plasma measured 1-3 weeks before experimental flights, suggesting that high quality birds had strong immune systems and greater flight capacity. Our findings indicate that flight performance is not diminished by prior immune challenge, but that flight while mounting an acute phase response negatively affects other aspects of immune function. These findings have important implications for our understanding of the transmission of avian diseases, as they suggest that birds can still migrate while fighting an infection.

Older can be better: physiological costs of paternal investment in the Florida scrub-jay

In species that undergo actuarial senescence, the value of current reproduction is predicted to increase relative to the value of future reproduction with age, as the probability of survival to another reproductive event is reduced. Therefore, life history theory predicts that aging animals should increase their investment in reproduction. However, an increase in reproductive investment may carry significant costs to the breeding individuals. We recorded provisioning rates of Florida scrub-jay male breeders, followed by their immediate capture to assess body condition and collect blood for an in vitro test of immunocompetence and an assay of baseline corticosterone for a measure of stress. Older males provisioned offspring and brooding mates at the highest rates. There was no evidence of any physiological deficits in males with high provisioning rates, independent of age. It appears that birds that survive to old age are high quality birds that maintain good physiological condition, which complements the value of experience and permits maximal investment in offspring.

Breeding Parameters and Recruitment in Feral PigeonsColumba liviaf.Domestica

This research was conducted on the Feral Pigeon population in Slupsk (NW Poland). Breeding parameters and the number of parental pairs' young recruited into the breeding population were determined for 52–112 marked pairs over three breeding seasons. Pairs had an average of 4.4 broods and produced 3.6 fledglings per breeding season. From 39 to 49% of pairs in various seasons did not have any young recruited. Every fourth pair (25–30%) had a single young bird recruited, from 12 to 20% of pairs — two young, from 4 to 11% — 3 young, and 6% of pairs had from four to six young recruited. The number of recruits depended on the breeding parameters of the parents: it was lowest among young pairs (low quality birds), those that began breeding late in the season, had a short breeding season, or low breeding success. In contrast, high quality birds with a long breeding season, the highest reproductive parameters and breeding success, had the most young recruited. Survival rate of young after leaving the nest was not found to be influenced by the starting date or the length of the breeding season of pairs. However, nesting conditions, such as pair density in colonies, may influence the fate of young birds after they leave the nest and are recruited.

The effects of variable foraging conditions on common murre ( Uria aalge) corticosterone concentrations and parental provisioning

This study investigated how total corticosterone concentrations, chick-feeding rates, and adult body mass changed with food availability from 1998 to 2000 in the same individually marked common murres ( Uria aalge). Capelin, the main prey species, arrived inshore by the onset of murre chick hatching in 1998 and 1999 (prey match years); whereas in 2000, hatching began approximately 1 week before the capelin arrived inshore to spawn (prey mismatch year). Serum corticosterone concentrations were higher in the same individuals in the prey mismatch year than they were in either of the match years. Birds sampled before peak capelin spawning in the mismatch year had higher corticosterone levels than murres sampled after peak spawning. Murres with higher corticosterone levels had higher chick-feeding rates and less mass loss in the mismatch year (compared to the match year 1999) than birds with lower levels. Corticosterone levels did not differ between birds that had not foraged for at least 12 h (brooded chick overnight) and those that had, suggesting that short-term food deprivation did not affect corticosterone concentrations. Taken together, these findings suggest that the difference between years reflects a baseline shift in corticosterone levels, particularly in the high-quality birds that were able to increase both corticosterone concentrations and foraging effort.

The timing of birds' breeding seasons: a review of experiments that manipulated timing of breeding

Reproductive success usually declines in the course of the season, which may be a direct effect of breeding time, an effect of quality (individuals with high phenotypic or environmental quality breeding early), or a combination of the two. Being able to distinguish between these possibilities is crucial when trying to understand individual variation in annual routines, for instance when to breed, moult and migrate. We review experiments with free-living birds performed to distinguish between the 'timing' and 'quality' hypothesis. 'Clean' manipulation of breeding time seems impossible, and we therefore discuss strong and weak points of different manipulation techniques. We find that the qualitative results were independent of manipulation technique (inducing replacement clutches versus cross-fostering early and late clutches). Given that the two techniques differ strongly in demands made on the birds, this suggests that potential experimental biases are limited. Overall, the evidence indicated that date and quality are both important, depending on fitness component and species, although evidence for the date hypothesis was found more frequently. We expected both effects to be prevalent, since only if date per se is important, does an incentive exist for high-quality birds to breed early. We discuss mechanisms mediating the seasonal decline in reproductive success, and distinguish between effects of absolute date and relative date, for instance timing relative to seasonal environmental fluctuations or conspecifics. The latter is important at least in some cases, suggesting that the optimal breeding time may be frequency dependent, but this has been little studied. A recurring pattern among cross-fostering studies was that delay experiments provided evidence for the quality hypothesis, while advance experiments provided evidence for the date hypothesis. This indicates that late pairs are constrained from producing a clutch earlier in the season, presumably by the fitness costs this would entail. This provides us with a paradox: evidence for the date hypothesis leads us to conclude that quality is important for the ability to breed early.

Pair duration, breeding success and divorce in a long-lived seabird: benefits of mate familiarity?

Previous studies have reported that pair duration is positively related to breeding performance and negatively related to divorce probability. According to the concept of ‘mate familiarity’, a long-term improvement in pair coordination with pair duration results in increased breeding performance. We assessed whether breeding experience, costs of mate change, individual quality and prior residence explained relationships involving pair duration in the kittiwake, Rissa tridactyla. We used specific samples (groups of individuals) where confounding factors were not relevant. In the complete data set (a heterogeneous group of individuals), breeding success probability increased with pair duration. Such variation in fitness may reflect changes at the individual level, or in the proportion of individuals of different quality. Breeding experience accounted for a sharp increase in success probability between the first and second years of pair duration. This trend was not observed in new pairs composed of only experienced breeders. Success probability did not increase with pair duration within groups of pairs with the same total duration, or in high-quality birds (using longevity as an index of quality). Finally, mate fidelity and site fidelity may be confounding factors. Prior residence (length of residence at the nest site) better explained variation in success and divorce probabilities than did pair duration. Overall, we found no evidence of a continuous increase in success probability with pair history that could be attributed to mate familiarity. This study highlights the need to consider within-population heterogeneity when assessing the evolution of life history traits.

Effect of floating nest platforms on the breeding performance of Black Terns

In 2003 and 2004, we placed 41 floating nest platforms on Grassy Lake in southeastern Wisconsin (USA) to test the hypothesis that reproductive success of Black Terns (Chlidonias niger) is limited by the quality of suitable nesting habitat. Extreme differences in water levels between these 2 yr provided a natural experiment to evaluate the effectiveness of the nest platforms during a drought year (2003) when natural nesting substrate was abundant, and a flood year (2004) when natural substrate was limited during the peak nesting period. Terns nested on 27 of 41 (66%) of the platforms in 2003 and 26 of 41 (63%) in 2004. No difference in the occupancy rate of platforms and natural nests was evident in 2003, but the pattern of clutch initiations early in the season in 2004 indicated that platforms were preferred over natural substrates. In 2003, nest survival rates did not differ between nests placed on platforms and those placed on natural substrates, but platform nests had significantly higher hatching success and nest survival rates in 2004. Both the Kaplan-Meier and Apparent Nest Success methods of calculating nest survival provided similar estimates. In both years, eggs laid on platforms were significantly larger than those laid on natural substrates, suggesting that platforms were occupied by high-quality birds. Our study indicates that floating nest platforms can be an effective management tool to enhance nesting habitat for Black Terns and other aquatic birds that construct floating nests, primarily because platforms provide nest sites when natural sites are not available due to flooding. Nest platforms also may be useful for addressing questions concerning habitat selection and parental quality. SINOPSIS. Efecto de plataformas artificiales para anidar en el desempe˜

Mark-recapture and behavioral ecology: a case study of Cliff Swallows

Mark–recapture and the statistical analysis methods associated with it offer great potential for investigating fitness components associated with particular behavioral traits. However, few behavioral ecologists have used these techniques. We illustrate the insights that have come from a long–term mark–recapture study of social behavior in Cliff Swallows (Petrochelidon pyrrhonota). The number of transient swallows passing through a colony per hour increased with colony size and was responsible in part for increased rates of ectoparasite introduction from outside the group into the larger colonies. Annual survival probabilities of males engaging in extra–pair copulation attempts were lower than those of males not seen to commit extra–pair copulations, suggesting that males who engage in this behavior may be inferior individuals and that females do not benefit from copulating with them. Females engaging in intraspecific brood parasitism had higher annual survival probabilities than ones either parasitized by others or not known to be either hosts or parasites. This suggests that parasitic females are high–quality birds and that brood parasitism is an effective reproductive tactic for increasing their fitness. By estimating first–year survival of chicks, we found that a clutch size of 4 eggs is often the most productive, on average, as measured by recruitment of offspring as breeders, although birds laying the more uncommon clutch size of 5 fledge more young on average. This helps to explain the observed clutch–size distribution in which clutch size 4 is the most commonly produced.

Effects of experimental food restriction and body-mass changes on the avian T-cell-mediated immune response

The T-cell-mediated immune response (CMI) of birds, measured with the phytohaemagglutinin skin test, is in most cases positively correlated with their body mass. This correlation, however, does not imply causality, since high-quality birds may be more immunocompetent as well as heavier at the time of sampling. We assessed this relationship experimentally by measuring the changes in body mass and CMI in individual captive yellow-legged gulls (Larus cachinnans) maintained with food provided ad libitum (control group), with no food (fasting group), or with one-third of their daily food requirements (subfeeding group). We identified a direct, nonlinear relationship between food intake, body mass, and CMI. Before the experiment started, body mass of birds (corrected for size) fed ad libitum did not correlate with their CMI, while a positive correlation was found after food restriction. This suggests that birds may reach a threshold above which increases in food intake and body mass do not enhance CMI. Thereaft...

Effects of experimental food restriction and body-mass changes on the avian T-cell-mediated immune response

The T-cell-mediated immune response (CMI) of birds, measured with the phytohaemagglutinin skin test, is in most cases positively correlated with their body mass. This correlation, however, does not imply causality, since high-quality birds may be more immunocompetent as well as heavier at the time of sampling. We assessed this relationship experimentally by measuring the changes in body mass and CMI in individual captive yellow-legged gulls (Larus cachinnans) maintained with food provided ad libitum (control group), with no food (fasting group), or with one-third of their daily food requirements (subfeeding group). We identified a direct, nonlinear relationship between food intake, body mass, and CMI. Before the experiment started, body mass of birds (corrected for size) fed ad libitum did not correlate with their CMI, while a positive correlation was found after food restriction. This suggests that birds may reach a threshold above which increases in food intake and body mass do not enhance CMI. Thereafter, food restriction caused decreases in CMI that were significantly correlated with the percentage of body mass lost by each bird. However, for birds that lost similar proportions of body mass, changes in CMI varied according to food-restriction treatment, the subfeeding group exhibiting a stronger CMI than the fasting group.

Effects of parental quality and effort on the reproduction of common terns

1. Age‐related patterns of reproduction in birds are often interpreted in terms of changing reproductive value with age: as residual reproductive value decreases with age birds have to increase their effort at younger age. In contrast, the ‘state‐based’ approach to life history postulates that not age per se determines reproductive decisions, but the ‘state’, reflecting condition or quality that may differ considerably between individuals of the same age. In this respect, we investigated the stability of body conditon, as well as individual quality differences in common terns Sterna hirundo and outline the role of parental quality and parental effort in reproductive performance. For lifetime identification we marked terns with passive transponders. Quality and effort were derived from body condition, which we monitored during the whole breeding season and every year for a period of up to 5 years. 2. Parameters of body condition and reproduction varied significantly between individuals, whereas intra‐individual variation over years was very low. Hence, body condition is very stable and differs considerable between birds. 3. Among the factors number of chicks, year and parental body condition, the latter was the only significant factor influencing chick growth rates. Furthermore, high growth rates of chicks were correlated with good female condition, and breeding success was positively correlated with body condition of both parents during incubation and chick‐rearing. 4. Parental effort increased significantly with increasing breeding success. The amount of expended effort depended on condition during incubation: mass loss was correlated with incubation mass, but not with mass during chick‐rearing. 5. Age was not an important factor in terms of condition or quality and also in terms of reproduction. The age independent condition reflects bird quality, enabling high quality birds to invest high parental effort resulting in high reproductive success over years, yet without negative consequences on future reproduction. 6. We conclude that in the common tern condition is a stable and age‐independent individual feature with substantial effects on reproduction. Hence, our data strongly support the ‘state‐based’ approach to life history. The high constancy in condition within and great differences between birds may also result in differences in lifetime reproductive success and fitness.

Reproductive Effort in Long-Lived Birds: Age-Specific Patterns of Condition, Reproduction and Survival in the Wandering Albatross

The condition, breeding performance and survival of the wandering albatross Diomedea exulans were studied in relation to the bird's reproductive experience and age. In both sexes, the body weight of immature birds increased steadily with age from 4 to 7 yr. In individual immature females it increased from one season to the next, and only those attaining a threshold value bred, irrespective of their age. At similar ages immature birds tended to be lighter than breeders. The weight of breeding males increased progressively throughout the breeding life, while that of females increased only during the first 15 yr. In contrast to most species the date of laying for first time breeders was earlier than for experienced birds. Experienced birds tended to lay at similar dates from one breeding season to the other. Birds failing to breed during the previous breeding season tended to lay earlier than successful individuals. The size of the egg and breeding success increased with the age and experience of the female to a maximum at 17-20 yr or 5-7 breeding attempts and then decreased in the older or more experienced birds. For first time breeders the breeding success and rate of return was the same for older individuals as for younger. The proportion of birds breeding one year after a failed breeding season was lower in birds breeding for the first time than in more experienced birds. There was no significant difference between the proportion of inexperienced and experienced birds returning to breed two yr after a successful breeding season. Birds with more than eight yr breeding experience also tended to postpone their return after a failed season longer than less experienced birds. Annual survival rate did not vary significantly with age between 4 and 22 yr. Birds older than 27 yr had a significantly lower survival than birds aged 16-22 yr (92.9% compared to 97.2%). This study suggests that in a very long-lived bird like the wandering albatross survival is not influenced by reproduction, particularly in the early ages because the onset of breeding is delayed until the risk of an increased mortality at first breeding has disappeared. Condition has probably an important influence in the decision to breed. The age related changes in breeding performance, condition and survival observed in the wandering albatross are probably influenced by the cumulative effects of an increase in skill and thereafter reproductive restraint at young ages, by the selection of high quality birds at intermediate ages and by senescence at older ages.