Kittiwake Chicks Research Articles

Indigo-dyed cellulose fibers and synthetic polymers in surface-feeding seabird chick regurgitates from the Gulf of Alaska

We provide evidence of anthropogenic materials ingestion in seabirds from a remote oceanic area, using regurgitates obtained from black-legged kittiwake (Rissa tridactyla) chicks from Middleton Island (Gulf of Alaska, USA). By means of GPS tracking of breeding adults, we identified foraging grounds where anthropogenic materials were most likely ingested. They were mainly located within the continental shelf of the Gulf of Alaska and near the Alaskan coastline. Anthropogenic cellulose fibers showed a high prevalence (85 % occurrence), whereas synthetic polymers (in the micro- and mesoplastics dimensional range) were less frequent (20 %). Most fibers (60 %) were blue and we confirmed the presence of indigo-dyed cellulosic fibers, characteristic of denim fabrics. In terms of mass, contamination levels were 0.077 μg g−1 wet weight and 0.009 μg g−1 wet weight for anthropogenic microfibers and synthetic polymers, respectively. These results represent the only recent report of contamination by anthropogenic fibers in seabirds from the Gulf of Alaska.

“Punishing” pecks and “siblicidal” pecks in kittiwake (Rissa tridactyla) chicks

The Black-legged Kittiwake gull (Rissa tridactyla) is noted for its suite of evolutionary adaptations to its extreme cliff-nesting habitat (Cullen, 1957) which distinguish it behaviourally in a number of ways from other gulls (Laridae). One such behaviour we observed was siblicide, the death of one chick from falling out of the nest as a consequence of agonistic harassment by the other (Dickins et al., 1985). This harassment involved what we termed “siblicidal pecks” inflicted by the dominant chick on its younger sib, not in the context of feeding. These we distinguished observationally from “punishing pecks”, also made by the dominant chick on its brood mate, specifically when the latter was begging for food from a parent, causing it to stop this behaviour in the short term.Though the evolution of siblicide initially seemed to present a paradox for Inclusive fitness theory it was soon seen to be a logical corollary thereof (O’Connor, 1978; Mock & Parker, 1998), and dependent upon key ecological variables. A number of subsequent studies of these factors in the kittiwake, largely from the ecological and ornithological literature, are here collated, and it is considered how these might be integrated with the application of concepts from operant psychology to chick and parent behaviours (Reed, 2015), to give a full account.

Sex and hatching order modulate the association between MHC-II diversity and fitness in early-life stages of a wild seabird.

Genes of the major histocompatibility complex (MHC) play a pivotal role in parasite resistance, and their allelic diversity has been associated with fitness variations in several taxa. However, studies report inconsistencies in the direction of this association, with either positive, quadratic or no association being described. These discrepancies may arise because the fitness costs and benefits of MHC diversity differ among individuals depending on their exposure and immune responses to parasites. Here, we investigated in black-legged kittiwake (Rissa tridactyla) chicks whether associations between MHC class-II diversity and fitness vary with sex and hatching order. MHC-II diversity was positively associated with growth and tick clearance in female chicks, but not in male chicks. Our data also revealed a positive association between MHC-II diversity and survival in second-hatched female chicks (two eggs being the typical clutch size). These findings may result from condition-dependent parasite infections differentially impacting sexes in relation to hatching order. We thus suggest that it may be important to account for individual heterogeneities in traits that potentially exert selective pressures on MHC diversity in order to properly predict MHC-fitness associations.

Prevailing weather conditions and diet composition affect chick growth and survival in the black-legged kittiwake

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 604:237-249 (2018) - DOI: https://doi.org/10.3354/meps12744 Prevailing weather conditions and diet composition affect chick growth and survival in the black-legged kittiwake Signe Christensen-Dalsgaard1,2,*, Roel F. May1, Robert T. Barrett3, Magdalene Langset1, Brett K. Sandercock1, Svein-Håkon Lorentsen1 1Norwegian Institute for Nature Research (NINA), PO Box 5685 Torgard, 7034 Trondheim, Norway 2Department of Biology, Norwegian University of Science and Technology (NTNU), Realfagbygget, 7491 Trondheim, Norway 3Department of Natural Sciences, Tromsø University Museum, PO Box 6050 Langnes, 9037 Tromsø, Norway *Corresponding author: signe.dalsgaard@nina.no ABSTRACT: To identify priorities for management of seabirds during the breeding season, it is important to understand the ecological mechanisms driving chick growth and survival. In this study, we examined the effects of diet and prevailing weather on the growth and survival of chicks of black-legged kittiwakes Rissa tridactyla over a 10 yr period at Anda, a seabird colony in northern Norway. We show that across all years, there was a significant effect of diet composition delivered to chicks on their growth and survival. A higher proportion of sandeel Ammodytes spp. in the chick diet was associated with an increase in daily growth rates, a pattern that was especially pronounced for the youngest chick in 2-chick broods. A high proportion of mesopelagic fish in the chick diet was associated with a decrease in survival, again, especially for the youngest chick in 2-chick broods. Periods of strong southerly winds also led to reduced survival, probably linked to nests being washed down from the colony. Growth rates of kittiwake chicks were negatively affected by wind speed, likely due to adults having to work more in the exposed habitats in strong winds, causing a reduction in the amount of food supplied to the chicks. Our results emphasise the importance of conservation of specific marine habitats shown to be important foraging areas in ensuring the reproductive success of seabirds. This might prove increasingly important if future climate regimes make ecological conditions more challenging for seabirds. KEY WORDS: Foraging effort · Mesopelagic fish · Nestling development · Prey availability · Rissa tridactyla · Sandeel · Wind conditions Full text in pdf format Supplementary material PreviousNextCite this article as: Christensen-Dalsgaard S, May RF, Barrett RT, Langset M, Sandercock BK, Lorentsen SH (2018) Prevailing weather conditions and diet composition affect chick growth and survival in the black-legged kittiwake. Mar Ecol Prog Ser 604:237-249. https://doi.org/10.3354/meps12744 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 604. Online publication date: October 04, 2018 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2018 Inter-Research.

Effects of developmental conditions on growth, stress and telomeres in black-legged kittiwake chicks.

Early-life conditions can drive ageing patterns and life history strategies throughout the lifespan. Certain social, genetic and nutritional developmental conditions are more likely to produce high-quality offspring: those with good likelihood of recruitment and productivity. Here, we call such conditions "favoured states" and explore their relationship with physiological variables during development in a long-lived seabird, the black-legged kittiwake (Rissa tridactyla). Two favoured states were experimentally generated by manipulation of food availability and brood size, while hatching order and sex were also explored as naturally generating favoured states. Thus, the favoured states we explored were high food availability, lower levels of sibling competition, hatching first and male sex. We tested the effects of favoured developmental conditions on growth, stress, telomere length (a molecular marker associated with lifespan) and nestling survival. Generation of favoured states through manipulation of both the nutritional and social environments furthered our understanding of their relative contributions to development and phenotype: increased food availability led to larger body size, reduced stress and higher antioxidant status, while lower sibling competition (social environment) led to lower telomere loss and longer telomere lengths in fledglings. Telomere length predicted nestling survival, and wing growth was also positively correlated with telomere length, supporting the idea that telomeres may indicate individual quality, mediated by favoured states.

Predation of Black-legged Kittiwake ChicksRissa tridactylaby a Peregrine FalconFalco peregrinus: Insights from Time-lapse Cameras

Abstract We directly recorded predation of Black-legged Kittiwake chicks (Rissa tridactyla) by a Peregrine Falcon (Falco peregrinus) using a remote time-lapse camera. Between 20 July 2013 and 23 July 2013, all four nests in the camera's field of view failed. A peregrine was recorded depredating chicks in two of these four nests. Periods of adult desertion at the other two nests strongly suggests chicks in these nests were depredated as well. Predation happened at night, a rarely documented behavior of the peregrine. Along with giving insights into peregrine hunting behavior, the use of remote cameras allows us to determine nest fate. Determining sources of chick mortality is invaluable for identifying causes of variability in productivity rates of colonial breeding birds.

Is natural hatching asynchrony optimal? An experimental investigation of sibling competition patterns in a facultatively siblicidal seabird

In unpredictable environments, any tactic that enables avian parents to adjust brood size and, thus, energy expenditure to environmental conditions should be favoured. Hatching asynchrony (HA), which occurs whenever incubation commences before clutch completion, may comprise such a tactic. For instance, the sibling rivalry hypothesis states that the hierarchy among chicks, concomitant to HA, should both facilitate the adjustment of brood size to environmental conditions and reduce several components of sibling competition as compared to synchronous hatching, at both brood and individual levels. We thus predicted that brood aggression, begging and feeding rates should decrease and that older chick superiority should increase with HA increasing, leading to higher growth and survival rates. Accordingly, we investigated the effects of an experimental upward and downward manipulation of HA magnitude on behaviour, growth and survival of black-legged kittiwake (Rissa tridactyla) chicks. In line with the sibling rivalry hypothesis, synchronous hatching increased aggression and tended to increase feeding rates by parents at the brood level. Begging rates, however, increased with HA contrary to our expectations. At the individual level, as HA magnitude increased, the younger chick was attacked and begged proportionally more often, experienced a slower growth and a higher mortality than its sibling. Overall, the occurrence of energetic costs triggered by synchronous hatching both for parents and chicks, together with the lower growth rate and increased mortality of the younger chick in highly asynchronous broods suggest that natural HA magnitude may be optimal.

Testosterone increases siblicidal aggression in black-legged kittiwake chicks (Rissa tridactyla)

To compete for parental food deliveries nestling birds have evolved diverse behaviors such as begging displays and sibling aggression. Testosterone has been suggested to be an important mechanism orchestrating such competitive behaviors, but evidence is scarce and often indirect. Siblicidal species provide an interesting case in which a clear dominance hierarchy is established and the dominant chicks lethally attack siblings. We experimentally elevated testosterone in chicks of a facultatively siblicidal species, the black-legged kittiwake, Rissa tridactyla, and showed that testosterone-treated chicks were more aggressive toward their sibling than were control chicks. In such facultatively siblicidal species, chicks normally exhibit intense aggression only when threatened by starvation. Indeed, we found that chicks in relatively poorer condition were more aggressive than were chicks in better condition, even among testosterone-treated chicks, suggesting the action of an additional signal modulating aggression. Relatively larger siblings were also more aggressive than were relatively smaller siblings, confirming the importance of size advantage in determining dominance hierarchies within the brood. In addition, testosterone increased aggression toward a simulated predator, indicating that in kittiwakes testosterone can increase aggression in contexts other than siblicide. Testosterone promoted aggression-mediated dominance, which increased begging although testosterone treatment did not have a significant separate effect on begging. Therefore, testosterone production in the kittiwake and most likely other siblicidal species seems an important fitness mediator already early in life, outside the sexual context and not only manifesting itself in aggressive behavior but also in dominance-mediated effects on food solicitation displays toward parents.

Maternal Androgens Increase Sibling Aggression, Dominance, and Competitive Ability in the Siblicidal Black-Legged Kittiwake (Rissa tridactyla)

Animals and plants routinely produce more offspring than they can afford to rear. Mothers can favour certain young by conferring on them competitive advantages such as a leading position in the birth sequence, more resources or hormones. Avian mothers create hatching asynchrony within a clutch and at the same time bestow the eggs with different concentrations of androgens that may enhance or counteract the competitive advantage experienced by early-hatching “core” young. In siblicidal birds, core young assume a dominant social position in the nest due to their size advantage and when threatened with starvation fatally attack subdominant later-hatching “marginal” young. A role for maternal androgens in siblicidal aggression has frequently been suggested but never tested. We studied this in the facultatively siblicidal black-headed kittiwake. We found that marginal eggs contain higher instead of lower concentrations of androgens than core eggs. Surprisingly, exposure to experimentally elevated yolk androgens increased sibling aggression and dominance, even though in nature marginal eggs never produce dominant chicks. We propose the “adoption facilitation hypothesis” to explain this paradox. This cliff-nesting colonial species has a high adoption rate: ejected marginal kittiwake chicks frequently fall into other nests containing chicks of similar or smaller size and exposure to yolk androgens might help them integrate themselves into a foster nest.

Halogenated organic contaminants and their correlations with circulating thyroid hormones in developing Arctic seabirds

Thyroid hormones are essential for normal growth and development and disruption of thyroid homeostasis can be critical to young developing individuals. The aim of the present study was to assess plasma concentrations of halogenated organic contaminants (HOCs) in chicks of two seabird species and to investigate possible correlations of HOCs with circulating thyroid hormone (TH) concentrations. Plasma from black-legged kittiwake (Rissa tridactyla) and northern fulmar (Fulmarus glacialis) chicks were sampled in Kongsfjorden, Svalbard in 2006. The samples were analyzed for thyroid hormones and a wide range of HOCs (polychlorinated biphenyls (PCBs), hydroxylated (OH−) and methylsulphoned (MeSO−) PCB metabolites, organochlorine pesticides (OCPs), brominated flame retardants (BFRs), and perfluorinated compounds (PFCs)).Concentrations of HOCs were generally low in kittiwake and fulmar chicks compared to previous reports. HOC concentrations were five times higher in fulmar chicks compared to in kittiwake chicks. PFCs dominated the summed HOCs concentrations in both species (77% in kittiwakes and 69% in fulmars).Positive associations between total thyroxin (TT4) and PFCs (PFHpS, PFOS, PFNA) were found in both species. Although correlations do not implicate causal relationships per se, the correlations are of concern as disruption of TH homeostasis may cause developmental effects in young birds.

Biotransformation of PCBs in Arctic seabirds: Characterization of phase I and II pathways at transcriptional, translational and activity levels

Arctic seabirds are exposed to a wide range of halogenated organic contaminants (HOCs). Exposure occurs mainly through food intake, and many pollutants accumulate in lipid-rich tissues. Little is known about how HOCs are biotransformed in arctic seabirds. In this study, we characterized biotransformation enzymes in chicks of northern fulmars ( Fulmarus glacialis) and black-legged kittiwakes ( Rissa tridactyla) from Kongsfjorden (Svalbard, Norway). Phase I and II enzymes were analyzed at the transcriptional, translational and activity levels. For gene expression patterns, quantitative polymerase chain reactions (qPCR), using gene-sequence primers, were performed. Protein levels were analyzed using immunochemical assays of western blot with commercially available antibodies. Liver samples were analyzed for phase I and II enzyme activities using a variety of substrates including ethoxyresorufin (cytochrome (CYP)1A1/1A2), pentoxyresorufin (CYP2B), methoxyresorufin (CYP1A), benzyloxyresorufin (CYP3A), testosterone (CYP3A/CYP2B), 1-chloro-2,4-nitrobenzene (CDNB) (glutathione S-transferase (GST)) and 4-nitrophenol (uridine diphosphate glucuronyltransferase (UDPGT)). In addition, the hydroxylated (OH-) polychlorinated biphenyls (PCBs) were analyzed in the blood, liver and brain tissue, whereas the methylsulfone (MeSO 2-) PCBs were analyzed in liver tissue. Results indicated the presence of phase I (CYP1A4/CYP1A5, CYP2B, and CYP3A) and phase II (GST and UDPGT) enzymes at the activity, protein and/or mRNA level in both species. Northern fulmar chicks had higher enzyme activity than black-legged kittiwake chicks. This in combination with the higher ΣOH-PCB to parent PCB ratios suggests that northern fulmar chicks have a different biotransformation capacity than black-legged kittiwake chicks.

Effect of nestling status and brood size on concentration of corticosterone of free-living kittiwake chicks

Vertebrates respond to perceived stressors through increased plasma concentrations of glucocorticoids. However, there is considerable variation within and across species in the circumstances and degree to which glucocorticoid levels are elevated. We measured baseline and acute stress-induced levels of corticosterone of free-living, black-legged kittiwake chicks ( Rissa tridactyla) across four consecutive breeding seasons in the northern Gulf of Alaska to determine the effect of hatching order and brood size on corticosterone levels of chicks. We sampled 12- to 15-day-old chicks from intact broods (i.e., no brood reduction) at three colonies from 2002–2005 ( n = 164). Baseline and stress-induced levels of corticosterone did not vary by hatching order or brood size. These results suggest that the adrenocortical function of kittiwake chicks from broods that survive intact through 12–15 days is not affected by either hatching order or brood size.

Effects of investigator disturbance on corticosterone concentrations of Black-legged Kittiwake chicks

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Experimental evidence of vocal recognition in young and adult black-legged kittiwakes

Individual recognition is required in most social interactions, and its presence has been confirmed in many species. In birds, vocal cues appear to be a major component of recognition. Curiously, vocal recognition seems absent or limited in some highly social species such as the black-legged kittiwake, Rissa tridactyla . Using playback experiments, we found that kittiwake chicks recognized their parents vocally, this capacity being detectable as early as 20 days after hatching, the youngest age tested. Mates also recognized each other's long calls. Some birds reacted to their partner's voice when only a part of the long call was played back. Nevertheless, only about a third of the tested birds reacted to their mate's or parents' call and we were unable to detect recognition among neighbours. We discuss the low reactivity of kittiwakes in relation to their cliff-nesting habit and compare our results with evidence of vocal recognition in other larids.

Interannual variation in the adrenal responsiveness of black-legged kittiwake chicks (Rissa tridactyla)

Over the last decade, field endocrinologists have explored the efficacy of using plasma corticosterone concentrations of breeding seabirds as an indicator of food availability and predictor of breeding success. However, studies have been predominately confined to adults and the results have been inconsistent. We examined the relationship between the productivity of black-legged kittiwakes (Rissa tridactyla) and the baseline and stress-induced corticosterone levels of 12–15 day-old kittiwake chicks in a multi-year study in Chiniak Bay, Kodiak, Alaska. We predicted that corticosterone levels would negatively correlate with productivity. Productivity decreased across years from relatively high levels in 2002, to very low levels in 2004 and 2005. Baseline corticosterone levels of the chicks did not increase consistently across years. Stress-induced corticosterone levels were statistically indistinguishable in high productivity years but increased significantly in low productivity years. The decline in kittiwake productivity coincided with warming ocean conditions, which, historically, are linked to declines in forage abundance for kittiwakes. Inconsistent changes in baseline corticosterone levels suggest some adult kittiwakes were able to buffer their chicks from poor foraging conditions. However, large increases in stress-induced corticosterone levels during the low productivity years indicate chicks were physiologically stressed for some period prior to sampling. Our results suggest that stress-induced corticosterone levels of kittiwake chicks are effective indicators of productivity in poor years, whereas the changes in baseline corticosterone levels across years are not as pronounced and therefore may not be as reliable.

Dynamics of anti-Borreliaantibodies in Black-legged Kittiwake (Rissa tridactyla) chicks suggest a maternal educational effect

In the presence of parasites, mothers can transfer specific immunoglobulins to their offspring. These antibodies are typically thought to provide protection until the juvenile produces its own immune response, but they may also act to educate the developing immune system so as to prepare the individual for future parasite challenge. We examined this hypothesis in a natural host–parasite system involving the Black-legged Kittiwake ( Rissa tridactyla (L., 1758)), the seabird tick ( Ixodes ( Ceratixodes ) uriae White, 1852), and the Lyme disease bacterium ( Borrelia burgdorferi s.l. (Johnston, 1984)). We compared the dynamics of anti-Borrelia antibodies in chicks between ages 5 and 20 days that received a large amount of maternal anti-Borrelia antibodies to those that did not. The results suggest that the presence of maternal antibodies against Borrelia increases the overall production of anti-Borrelia immunoglobulins by chicks and support the existence of an adaptive maternal effect. Experimental approaches are now called for to better appraise the ecological and evolutionary consequences of the maternal transfer of antibodies in host–parasite interactions.

Benefits and costs of increased levels of corticosterone in seabird chicks

Seabird chicks respond to food shortages by increasing corticosterone (cort) secretion, which is probably associated with fitness benefits and costs. To examine this, we experimentally increased levels of circulating cort in captive black-legged kittiwake chicks fed ad libitum. We found that cort-implanted chicks begged more frequently and were more aggressive compared to controls. These behavioral modifications must be beneficial to chicks as they facilitate acquisition of food from the parents and might trigger brood reduction and reduced competition for food. Cort-implanted chicks also increased food intake; however, their growth rates were similar to controls. To examine the costs of chronically increased circulating levels of cort, we removed cort implants and, after a 10-day recovery period, tested cognitive abilities of young kittiwakes. We found that the ability of kittiwakes to associate a visual cue with the presence of food in a choice situation was compromised by the experimental elevation of cort during development. To examine the long-term costs of increased levels of cort, 8 months later we tested the performance of the same individuals in a spatial task requiring them to make a detour around a barrier in order to escape from an enclosure. Individuals treated with cort during development took significantly more time to solve this task compared to controls. The results of this study suggest that the adrenocortical response of a developing bird to environmental stressors is associated with both benefits (increased food intake, foraging behavior, and aggression) and costs (low growth efficiency and compromised cognitive abilities later in life). This provides an evolutionary framework for relating juvenile physiological traits to fitness of birds in subsequent life-history stages.

Dietary restriction causes chronic elevation of corticosterone and enhances stress response in red-legged kittiwake chicks.

Release of corticosterone in hungry kittiwake chicks facilitates begging and allows them to restore depleted energy reserves by increasing parental food provisioning. However, in order to avoid detrimental effects of chronic elevation of corticosterone, chicks might suppress adrenocortical activity in response to prolonged food shortages. In this study we examined temporal dynamics of corticosterone release in red-legged kittiwake (Rissa brevirostris) chicks exposed to prolonged restrictions in energy content and/or nutritional quality (low versus high lipid content) of their food. Starting at the age of 15 days, chicks were fed either high- or low-lipid fish at 40%, 65%, and 100% of ad libitum energy intake. Body mass measurements and baseline plasma samples were taken on a weekly basis after beginning of the treatment. After 3 weeks of treatment, chicks were exposed to a standardized acute handling and restraint stress protocol, where in addition to a baseline sample, three plasma samples were taken at intervals up to 50 min. We found that food-restricted chicks had lower body mass, chronically (during 2-3 weeks) elevated baseline and higher acute stress-induced levels of corticosterone compared to chicks fed ad libitum. Low lipid content of food further exacerbated these effects. An increase in baseline levels of corticosterone was observed within a week after energy requirements of food-restricted chicks exceeded their daily energy intake. A tendency for suppression of adrenocortical activity was observed in treatments fed low-lipid diets only at the end of the experiment. We suggest that nest-bound chicks, if food-stressed, might suffer deleterious effects of chronic elevation of corticosterone.

Immunocompetence of nestling great tits in relation to rearing environment and parentage

Theoretical models of host–parasite coevolution assume a partially genetic basis to the variability in susceptibility to parasites among hosts, for instance as a result of genetic variation in immune function. However, few empirical data exist for free–living vertebrate hosts to support this presumption. In a cross–fostering experiment with nestling great tits, by comparing nestlings of the same origin we investigated (i) the variance in host resistance against an ectoparasite due to a common genetic origin, (ii) the effect of ectoparasite infestation on cell–mediated immunity and (iii) the variance in cell–mediated immunity due to a common genetic origin. Ectoparasitic hen fleas can impair the growth of nestling great tits and nestling growth was therefore taken as a measure of host susceptibility. A common origin did not account for a significant part of the variation in host susceptibility to fleas. There was no significant overall effect of fleas on nestling growth or cell–mediated immunity, as assessed by a cutaneous hypersensitivity response. A common rearing environment explained a significant part of the variation in cell–mediated immunity among nestlings, mainly through its effect on nestling body mass. The variation in cell–mediated immunity was also related to a common origin. However, the origin–related variation in body mass did not account for the origin–related differences in cell–mediated immunity. The results of the present study thus suggest heritable variation in cell–mediated immunity among nestling great tits.

The adrenocortical stress-response of Black-legged Kittiwake chicks in relation to dietary restrictions

In this study we examined hormonal responses of Black-legged Kittiwake (Rissa tridactyla) chicks to experimental variations in energy content and nutri- tional quality (low or high lipid to protein ratio, LPR) of their food. Starting at the age of 10 days, chicks were fed either high or low LPR fish at 30, 50, 70 and 100% of ad libitum energy intake. After 20 days of treatment, chicks were exposed to a standardized acute handling and re- straint stress protocol, where a baseline sample was ta- ken immediately after taking a chick from the nest, and three additional blood samples were taken at intervals up to 50 min. Testosterone and corticosterone titres in plasma were measured via radioimmunoassay. We found that baseline testosterone levels were not significantly aAected by the experimental treatments. Food-restricted chicks had elevated baseline and acute stress-induced levels of corticosterone compared to chicks fed ad libi- tum. An elevation of circulating levels of corticosterone in energetically stressed individuals was further magni- fied by low nutritional quality of food. Baseline and acute stress-induced corticosterone levels of chicks were negatively correlated with their fat reserves. We con- clude that the physiological condition of Black-legged Kittiwake chicks can be assessed reliably by measuring circulating levels of corticosterone. We discuss short- and long-term eAects of elevated corticosterone secretion in food-stressed nest-bound chicks.