Transient growth‐enhancing effects of elevated maternal thyroid hormones at no apparent oxidative cost during early postnatal period

Maternal thyroid hormones (THs) have been proven crucial for embryonic development in humans, but their influence within the natural variation on wild animals remains unknown. So far the only two studies that experimentally investigated the potential fitness consequences of maternal THs in birds found inconsistent results. More studies are thus required to assess the general effects of maternal THs and their influences on more behavioral and physiological parameters. In this study, we experimentally elevated yolk TH content in a wild migratory passerine species, the collared flycatcher Ficedula albicollis, to investigate the effects on hatching success, nestling growth and oxidative stress. We found that TH‐injected eggs had a higher hatching success, and the nestlings hatched from TH‐injected eggs were heavier and larger than control nestlings, but only during the early postnatal period. These differences vanished by fledging. Nestlings from TH‐injected eggs exhibited lower activity of the glutathione‐s‐transferase, a major antioxidant enzyme, than control nestlings at day 12, a few days before fledging, but they did not differ in oxidative damage and overall intracellular oxidative state. These results suggest that the early growth‐enhancing effects incurred no observable oxidative stress. We hypothesize that such a transient growth‐enhancing effect might be adaptive in advancing the development and maturation of the offspring so they are well‐prepared in time for the upcoming migration. Further studies investigating whether such advancing effects can influence long‐term fitness, will be more than valuable.     

Large‐brained birds suffer less oxidative damage

Large brains (relative to body size) might confer fitness benefits to animals. Although the putative costs of well‐developed brains can constrain the majority of species to modest brain sizes, these costs are still poorly understood. Given that the neural tissue is energetically expensive and demands antioxidants, one potential cost of developing and maintaining large brains is increased oxidative stress (‘oxidation exposure’ hypothesis). Alternatively, because large‐brained species exhibit slow‐paced life histories, they are expected to invest more into self‐maintenance such as an efficacious antioxidative defence machinery (‘oxidation avoidance’ hypothesis). We predict decreased antioxidant levels and/or increased oxidative damage in large‐brained species in case of oxidation exposure, and the contrary in case of oxidation avoidance. We address these contrasting hypotheses for the first time by means of a phylogenetic comparative approach based on an unprecedented data set of four redox state markers from 85 European bird species. Large‐brained birds suffered less oxidative damage to lipids (measured as malondialdehyde levels) and exhibited higher total nonenzymatic antioxidant capacity than small‐brained birds, whereas uric acid and glutathione levels were independent of brain size. These results were not altered by potentially confounding variables and did not depend on how relative brain size was quantified. Our findings partially support the ‘oxidation avoidance’ hypothesis and provide a physiological explanation for the linkage of large brains with slow‐paced life histories: reduced oxidative stress of large‐brained birds can secure brain functionality and healthy life span, which are integral to their lifetime fitness and slow‐paced life history.     

Relationships among oxidative status,breeding conditions and life‐history traits in free‐living Great Tits Parus major and Common Starlings Sturnus vulgaris

The interest shown by ecologists in antioxidants and oxidative stress as potential modulators of life‐history trade‐offs has expanded greatly in recent years. However, we still know very little about natural variation in oxidative damage and antioxidant capacity in free‐living animals. In this study, we describe the natural variation in three components of oxidative balance in nestlings and breeding females in free‐living Great Tits Parus major and Common Starlings Sturnus vulgaris in central Italy, and relate these to breeding conditions and life‐history traits. Our results suggest that there are associations among oxidative physiology, reproductive activity, growth pattern and season in wild birds, but that the nature of these associations might be species‐specific rather than general across species.     

Comparative migration strategies of wild and captive‐bred Asian Houbara Chlamydotis macqueenii

For migratory species, the success of population reintroduction or reinforcement through captive‐bred released individuals depends on survivors undertaking appropriate migrations. We assess whether captive‐bred Asian Houbara Chlamydotis macqueenii from a breeding programme established with locally sourced individuals and released into suitable habitat during spring or summer undertake similar migrations to those of wild birds. Using satellite telemetry, we compare the migrations of 29 captive‐bred juveniles, 10 wild juveniles and 39 wild adults (including three birds first tracked as juveniles), examining migratory propensity (proportion migrating), timing, direction, stopover duration and frequency, efficiency (route deviation), and wintering and breeding season locations. Captive‐bred birds initiated autumn migration an average of 20.6 (±4.6 se) days later and wintered 470.8 km (±76.4) closer to the breeding grounds, mainly in Turkmenistan, northern Iran and Afghanistan, than wild birds, which migrated 1217.8 km (±76.4), predominantly wintering in southern Iran and Pakistan (juveniles and adults were similar). Wintering locations of four surviving captive‐bred birds were similar in subsequent years (median distance to first wintering site = 70.8 km, range 6.56–221.6 km), suggesting that individual captive‐bred birds (but not necessarily their progeny) remain faithful to their first wintering latitude. The migratory performance of captive‐bred birds was otherwise similar to that of wild juveniles. Although the long‐term fitness consequences for captive‐bred birds establishing wintering sites at the northern edge of those occupied by wild birds remain to be quantified, it is clear that the pattern of wild migrations established by long‐term selection is not replicated. If the shorter migration distance of young captive‐bred birds has a physiological rather than a genetic basis, then their progeny may still exhibit wild‐type migration. However, as there is a considerable genetic component to migration, captive breeding management must respect migratory population structure as well as natal and release‐site fidelity.     

Migrating songbirds on stopover prepare for,and recover from,oxidative challenges posed by long‐distance flight

Managing oxidative stress is an important physiological function for all aerobic organisms, particularly during periods of prolonged high metabolic activity, such as long‐distance migration across ecological barriers. However, no previous study has investigated the oxidative status of birds at different stages of migration and whether that oxidative status depends on the condition of the birds. In this study, we compared (1) energy stores and circulating oxidative status measures in (a) two species of Neotropical migrants with differing migration strategies that were sampled at an autumn stopover site before an ecological barrier; and (b) a species of trans‐Saharan migrant sampled at a spring stopover site after crossing an ecological barrier; and (2) circulating oxidative measures and indicators of fat metabolism in a trans‐Saharan migrant after stopovers of varying duration (0–8 nights), based on recapture records. We found fat stores to be positively correlated with circulating antioxidant capacity in Blackpoll Warblers and Red‐eyed Vireos preparing for fall migration on Block Island, USA, but uncorrelated in Garden Warblers on the island of Ponza, Italy, after a spring crossing of the Sahara Desert and Mediterranean Sea. In all circumstances, fat stores were positively correlated with circulating lipid oxidation levels. Among Garden Warblers on the island of Ponza, fat anabolism increased with stopover duration while oxidative damage levels decreased. Our study provides evidence that birds build antioxidant capacity as they build fat stores at stopover sites before long flights, but does not support the idea that antioxidant stores remain elevated in birds with high fuel levels after an ecological barrier. Our results further suggest that lipid oxidation may be an inescapable hazard of using fats as the primary fuel for flight. Yet, we also show that birds on stopover are capable of recovering from the oxidative damage they have accrued during migration, as lipid oxidation levels decrease with time on stopover. Thus, the physiological strategy of migrating songbirds may be to build prophylactic antioxidant capacity in concert with fuel stores at stopover sites before a long‐distance flight, and then repair oxidative damage while refueling at stopover sites after long‐distance flight.     

Year‐round spatial movements and trophic ecology of Trindade Petrels (Pterodroma arminjoniana)

Trindade Petrels (Pterodroma arminjoniana) are vulnerable gadfly petrels that breed on the remote Trindade Island, located ~1100 km off the Brazilian coast. Little is known about their spatial ecology, and their trophic ecology has only been described for the breeding season. We tagged four Trindade Petrels with global location sensing loggers (GLS) from October 2013 to November 2014 and sampled the blood and feathers (innermost primary and the eighth secondary) of 14 individuals to evaluate their year‐round spatial and isotopic ecology. We examined individual distributions, habitat use and suitability, activity, and isotopic values during the breeding, migration, and non‐breeding periods. Trindade Petrels used areas in the southwest Atlantic Ocean (between 10°N and 50°S in latitude) during the breeding season. They migrated through pelagic waters of the tropical Atlantic to the northwest Atlantic, where they spent the non‐breeding season. Trindade Petrels used mostly tropical to subtropical waters in areas of intermediate to high wind speeds and low marine productivity. Individuals spent more time foraging at night than during the day. During the breeding season, birds in northerly areas had higher carbon‐13 values, and birds that used more pelagic areas foraged on prey at a higher trophic level (higher nitrogen‐15 values) than those in more southern and coastal areas. Isotopic values during the breeding, migration, and non‐breeding periods differed, possibly due to differences among individuals in their at‐sea distribution throughout the year. We confirmed the non‐breeding distribution of Trindade Petrels, which was previously known only from vessel sightings and stranded birds. Our results also suggest a strong temporal segregation in the at‐sea distribution and trophic ecology between two groups of individuals, which might indicate the existence of two separate breeding populations.     

“Closer‐to‐home” strategy benefits juvenile survival in a long‐distance migratory bird

Human‐induced changes in the climate and environment that occur at an unprecedented speed are challenging the existence of migratory species. Faced with these new challenges, species with diverse and flexible migratory behaviors may suffer less from population decline, as they may be better at responding to these changes by altering their migratory behavior. At the individual level, variations in migratory behavior may lead to differences in fitness and subsequently influence the population's demographic dynamics. Using lifetime GPS bio‐logging data from 169 white storks (Ciconia ciconia), we explore whether the recently shortened migration distance of storks affects their survival during different stages of their juvenile life. We also explore how other variations in migratory decisions (i.e., time, destination), movement activity (measured using overall body dynamic acceleration), and early life conditions influence juvenile survival. We observed that their first autumn migration was the riskiest period for juvenile white storks. Individuals that migrated shorter distances and fledged earlier experienced lower mortality risks. In addition, higher movement activity and overwintering “closer‐to‐home” (with 84.21% of the tracked individuals stayed Europe or North Africa) were associated with higher survival. Our study shows how avian migrants can change life history decisions over only a few decades, and thus it helps us to understand and predict how migrants respond to the rapidly changing world.     

Short‐ and long‐term consequences of early developmental conditions: a case study on wild and domesticated zebra finches

Divergent selection pressures among populations can result not only in significant differentiation in morphology, physiology and behaviour, but also in how these traits are related to each other, thereby driving the processes of local adaptation and speciation. In the Australian zebra finch, we investigated whether domesticated stock, bred in captivity over tens of generations, differ in their response to a life‐history manipulation, compared to birds taken directly from the wild. In a ‘common aviary’ experiment, we thereto experimentally manipulated the environmental conditions experienced by nestlings early in life by means of a brood size manipulation, and subsequently assessed its short‐ and long‐term consequences on growth, ornamentation, immune function and reproduction. As expected, we found that early environmental conditions had a marked effect on both short‐ and long‐term morphological and life‐history traits in all birds. However, although there were pronounced differences between wild and domesticated birds with respect to the absolute expression of many of these traits, which are indicative of the different selection pressures wild and domesticated birds were exposed to in the recent past, manipulated rearing conditions affected morphology and ornamentation of wild and domesticated finches in a very similar way. This suggests that despite significant differentiation between wild and domesticated birds, selection has not altered the relationships among traits. Thus, life‐history strategies and investment trade‐offs may be relatively stable and not easily altered by selection. This is a reassuring finding in the light of the widespread use of domesticated birds in studies of life‐history evolution and sexual selection, and suggests that adaptive explanations may be legitimate when referring to captive bird studies.     

Individual‐based ecology of coastal birds

Conservation objectives for non‐breeding coastal birds (shorebirds and wildfowl) are determined from their population size at coastal sites. To advise coastal managers, models must predict quantitatively the effects of environmental change on population size or the demographic rates (mortality and reproduction) that determine it. As habitat association models and depletion models are not able to do this, we developed an approach that has produced such predictions thereby enabling policy makers to make evidence‐based decisions. Our conceptual framework is individual‐based ecology, in which populations are viewed as having properties (e.g. size) that arise from the traits (e.g. behaviour, physiology) and interactions of their constituent individuals. The link between individuals and populations is made through individual‐based models (IBMs) that follow the fitness‐maximising decisions of individuals and predict population‐level consequences (e.g. mortality rate) from the fates of these individuals. Our first IBM was for oystercatchers Haematopus ostralegus and accurately predicted their density‐dependent mortality. Subsequently, IBMs were developed for several shorebird and wildfowl species at several European sites, and were shown to predict accurately overwinter mortality, and the foraging behaviour from which predictions are derived. They have been used to predict the effect on survival in coastal birds of sea level rise, habitat loss, wind farm development, shellfishing and human disturbance. This review emphasises the wider applicability of the approach, and identifies other systems to which it could be applied. We view the IBM approach as a very useful contribution to the general problem of how to advance ecology to the point where we can routinely make meaningful predictions of how populations respond to environmental change.     

Around the Mediterranean: an extreme example of loop migration in a long‐distance migratory passerine

An important issue in migration research is how small‐bodied passerines pass over vast geographical barriers; in European–African avian migration, these are represented by the Mediterranean Sea and the Sahara Desert. Eastern (passing eastern Mediterranean), central (passing Apennine Peninsula) and western (via western Mediterranean) major migration flyways are distinguished for European migratory birds. The autumn and spring migration routes may differ (loop migration) and there could be a certain level of individual flexibility in how individuals navigate themselves during a single migration cycle. We used light‐level loggers to map migration routes of barn swallows Hirundo rustica breeding in the centre of a wide putative contact zone between the northeastern and southernwestern European populations that differ in migration flyways utilised and wintering grounds. Our data documented high variation in migration patterns and wintering sites of tracked birds (n = 19 individuals) from a single breeding colony, with evidence for loop migration in all but one of the tracked swallows. In general, two migratory strategies were distinguished. In the first, birds wintering in a belt stretching from southcentral to southern Africa that used an eastern route for both the spring and autumn migration, then shifted their spring migration eastwards (anti‐clockwise loops, n = 12). In the second, birds used an eastern or central route to their wintering grounds in central Africa, shifting the spring migration route westward (clockwise loops, n = 7). In addition, we observed an extremely wide clockwise loop migration encompassing the entire Mediterranean, with one individual utilising both the eastern (autumn) and western (spring) migratory flyway during a single annual migration cycle. Further investigation is needed to ascertain whether clockwise migratory loops encircling the entire Mediterranean also occur other small long‐distance passerine species.     

Relationship between arrival timing and breeding success of intra‐tropical migratory Fork‐tailed Flycatchers (Tyrannus savana)

For migratory birds, early arrival at breeding areas has many benefits, such as acquisition of better territories and mates. This strategy has been found in numerous species breeding at north‐temperate latitudes, but has not been yet reported for intra‐tropical migratory species. We evaluated the relationship between arrival date, initiation of breeding, and breeding success of Fork‐tailed Flycatchers (Tyrannus savana) breeding in southeastern Brazil and overwintering in northern South America. We color‐banded adult flycatchers during three breeding seasons and searched for them during the following breeding seasons. We also monitored nests from construction until either failure or fledging of young. We found that: (1) male Fork‐tailed Flycatchers arrived at the breeding site earlier than females, (2) males that arrived earlier had greater breeding success, and (3) nests where eggs were laid earlier in the breeding season were more likely to be successful than those where eggs were laid later. Male Fork‐tailed Flycatchers appeared to benefit from early arrival at a tropical breeding site, potentially mediated by their ability to acquire a high‐quality territory and mate as early as possible, and by the ability of their mate to begin breeding as early as possible. Breeding success for female Fork‐tailed Flycatchers may be determined primarily by a combination of the arrival date of their mate and how quickly they can begin breeding. Our results suggest that protandry occurs in an intra‐tropical migratory bird and that early arrival of males and early initiation of reproduction by females results in greater reproductive success. A better understanding of the underlying mechanisms that control the timing of migration and reproduction of this and other intra‐tropical migratory species is important for evaluating the challenges they face in light of current and future rapid environmental changes.     

Migration of wild and captive‐bred Little Bustards Tetrax tetrax: releasing birds from Spain threatens attempts to conserve declining French populations

Populations of the Little Bustard Tetrax tetrax in the farmlands of Europe have declined greatly over the last century. In Western Europe, France now holds the only remaining migratory population, which currently numbers fewer than 300 displaying males. However, the movements of these birds are virtually unknown, in spite of the important implications of this information for the conservation of this species. We identified migratory movements and overwintering areas of French migratory populations, using wild individuals fitted with satellite or radio‐transmitters. Little Bustards completed their migration journey over a relatively short time period (2–5 days), with nocturnal migration flights of 400–600 km per night. All birds overwintered in Iberia. In addition, we tested the consequences of captive rearing on migratory movements. French wild adults and French captive‐bred juveniles behaved similarly with regard to migration, suggesting that hand‐raising does not alter migratory movements. However, birds originating from eggs collected in Spain and reared in western France did not migrate, suggesting a genetic component to migratory behaviour. These results therefore suggest that a conservation strategy involving the release in France of birds hatched from eggs collected in Spain may imperil the expression of migratory movements of the French population. More generally, to maintain the integrity of native populations, the introduced individuals should mimic their migratory movements and behaviour.     

Oxidative status and stress during highly energetic life‐history stages of Chinstrap Penguins: breeding versus molting

Life‐history stages such as reproduction and molt are energetically costly. Reproductive costs include those associated not only with offspring production, but also protecting and provisioning young. Costs typically associated with molting include decreased thermoregulatory and locomotive performance, and increased metabolic and nutritional costs. Energetic demands may disrupt homeostasis, particularly in terms of its maintenance (e.g., oxidative stress and immunity). Few investigators have explored the relationship between effort (increased metabolic rate) and oxidative status and stress by comparing life‐history stages with different energetic demands. However, comparative studies are crucial for understanding the processes of energy allocation and their consequences for different physiological functions. Our objective was to determine how two highly demanding life‐history stages, breeding and molting, affected oxidative balance in Chinstrap Penguins (Pygoscelis antarcticus), a species where these two activities do not overlap. We found that the heterophil/lymphocyte (H/L) ratio was significantly higher during breeding than molting; oxidative damage was also higher during breeding. In contrast, we found no significant differences between these stages in total antioxidant capacity. We also found sex differences, with males having greater oxidative damage than females. Our results suggest that breeding is more stressful and more demanding for Chinstrap Penguins than molting, and provide further support for the relationship between effort, in terms of increased metabolic rate, and oxidative balance.     

Strong between‐site variation in New Caledonian crows’ use of hook‐tool‐making materials

Functional tool use requires the selection of appropriate raw materials. New Caledonian crows Corvus moneduloides are known for their extraordinary tool‐making behaviour, including the crafting of hooked stick tools from branched vegetation. We describe a surprisingly strong between‐site difference in the plant materials used by wild crows to manufacture these tools: crows at one study site use branches of the non‐native shrub Desmanthus virgatus, whereas only approximately 7 km away, birds apparently ignore this material in favour of the terminal twigs of an as‐yet‐unidentified tree species. Although it is likely that differences in local plant communities drive this striking pattern, it remains to be determined how and why crows develop such strong site‐specific preferences for certain raw materials.     

Hatching asynchrony and growth trade‐offs within domesticated and wild zebra finch,Taeniopygia guttata,broods

The Australian zebra finch, Taeniopygia guttata, is a widely used model organism, yet few studies have compared domesticated and wild birds with the aim of examining its relevance as an evolutionary model species. Domestic and wild broods hatch over approximately 4 and 2 days, respectively, which is important given that nestlings can fledge after as little as 12 days, although 16–18 days is common. We aimed to evaluate the extent to which the greater hatching asynchrony in domestic stock may effect reproductive success through greater variance in size hierarchies, variance in within‐brood growth rates, and partial brood mortality. Therefore, by simultaneously controlling brood sizes and experimentally manipulating hatching intervals in both domesticated and wild birds, we investigated the consequences of hatching intervals for fledging success and nestling growth patterns, as well as trade‐offs. Fledging success was similarly high in domestic and wild broods of either hatching pattern. Nonetheless, between‐brood analyses revealed that domestic nestlings had significantly higher masses, larger skeletal characters, and longer wings than their wild counterparts, although wild nestlings had comparable wing lengths at the pre‐fledging stage. Moreover, within‐brood analyses revealed only negligible differences between domestic and wild nestlings, and larger effects of hatching order and hatching pattern. Therefore, despite significant differences in the hatching intervals, and the ultimate size achieved by nestlings, the domestication process does not appear to have significantly altered nestling growth trade‐offs. The present study provides reassuring evidence that studies involving domesticated zebra finches, or other domesticated model organisms, may provide reasonable adaptive explanations in behavioural and evolutionary ecology. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100 , 763–773.     

Flying with diverse passengers: greater richness of parasitic nematodes in migratory birds

Environmental changes are simultaneously affecting parasitic diseases and animal migrations, making it important to understand the disease dynamics of migratory species, including their range of infections and investment into defences. There is an urgent need for such knowledge because migratory animals, especially birds, are important for pathogen transmission and also particularly sensitive to environmental changes. Here we compare the nematode species richness and relative immune investment (via relative spleen size) of almost 200 migratory and non‐migratory species within three diverse groups of birds (Anseriformes, Accipitriformes and Turdidae) with worldwide distributions and varied ecology. Our results provide the first large‐scale demonstration that migratory birds face greater challenge from macroparasites as they have significantly dissimilar nematode fauna and higher nematode species richness compared to non‐migratory species. Even though birds with relatively large spleens had more nematode species, there was no difference in relative spleen size between migratory and non‐migratory bird species. The physiological stress of migration can be exacerbated by the potential range of pathologies induced by their richer nematode communities, particularly in combination with environmental perturbations. Altered migration stemming from global changes can also have important consequences for nematode transmission. Synthesis Most studies on parasites of migratory birds versus non‐migratory birds focus upon blood parasites; here we compared the diversity of another important parasite group – nematodes (roundworms) in three orders of birds. We found for any given order, migratory species and species with proportionally larger spleens generally have a wider range of nematodes. It is unclear why migratory species harbour more nematode species. Global climate change is expected to influence both bird migration patterns and infectious diseases, which may increase host susceptibility to parasitism and also introduce diverse nematodes to new areas and potential hosts.     

Oxidative damage and anti-oxidant capacity in two migratory bird species at a stop-over site

We quantified in the garden warbler (Sylvia borin) and the barn swallow (Hirundo rustica), two long-distance migratory songbirds, the early oxidative damage (ROMs) and plasma anti-oxidant capacity (OXY) variation of individuals caught at a stop-over site after a sustained flight across the sea, during spring migration. Our main goal was to quantify the oxidative damage and anti-oxidant capacity variation in these two migratory species in relation to fat and muscle stores. The birds were sampled in Ponza, a small island along the migratory route of these species. The levels of ROMs and OXY did not show any differences between the two species and in general were higher in individuals with higher fat and protein stores. Nevertheless, the balance between ROMs and OXY was better in individuals in good condition. These patterns were similar in both species. No sex differences emerged for both ROMs and OXY in the barn swallow, the only species that could be sexed. Both markers of oxidative stress did not show any significant variation across a 30-min restrained experiment. These data are the first of this kind in wild birds in a migratory context and suggest that individuals in better condition are exposed to lower oxidative stress, providing an indirect evidence of the oxidative cost caused by prolonged flights.     

Cell‐to‐cell heterogeneity emerges as consequence of metabolic cooperation in a synthetic yeast community

Cells that grow together respond heterogeneously to stress even when they are genetically similar. Metabolism, a key determinant of cellular stress tolerance, may be one source of this phenotypic heterogeneity, however, this relationship is largely unclear. We used self‐establishing metabolically cooperating (SeMeCo) yeast communities, in which metabolic cooperation can be followed on the basis of genotype, as a model to dissect the role of metabolic cooperation in single‐cell heterogeneity. Cells within SeMeCo communities showed to be highly heterogeneous in their stress tolerance, while the survival of each cell under heat or oxidative stress, was strongly determined by its metabolic specialization. This heterogeneity emerged for all metabolite exchange interactions studied (histidine, leucine, uracil, and methionine) as well as oxidant (H₂O₂, diamide) and heat stress treatments. In contrast, the SeMeCo community collectively showed to be similarly tolerant to stress as wild‐type populations. Moreover, stress heterogeneity did not establish as sole consequence of metabolic genotype (auxotrophic background) of the single cell, but was observed only for cells that cooperated according to their metabolic capacity. We therefore conclude that phenotypic heterogeneity and cell to cell differences in stress tolerance are emergent properties when cells cooperate in metabolism.     

sOAR: a tool for modelling optimal animal life‐history strategies in cyclic environments

Periodic environments determine the life cycle of many animals across the globe and the timing of important life history events, such as reproduction and migration. These adaptive behavioural strategies are complex and can only be fully understood (and predicted) within the framework of natural selection in which species adopt evolutionary stable strategies. We present sOAR, a powerful and user‐friendly implementation of the well‐established framework of optimal annual routine modelling. It allows determining optimal animal life history strategies under cyclic environmental conditions using stochastic dynamic programming. It further includes the simulation of population dynamics under the optimal strategy. sOAR provides an important tool for theoretical studies on the behavioural and evolutionary ecology of animals. It is especially suited for studying bird migration. In particular, we integrated options to differentiate between costs of active and passive flight into the optimal annual routine modelling framework, as well as options to consider periodic wind conditions affecting flight energetics. We provide an illustrative example of sOAR where food supply in the wintering habitat of migratory birds significantly alters the optimal timing of migration. sOAR helps improving our understanding of how complex behaviours evolve and how behavioural decisions are constrained by internal and external factors experienced by the animal. Such knowledge is crucial for anticipating potential species’ response to global environmental change.