Productivity of the Black-legged Kittiwake Rissa tridactyla required to maintain numbers

Capsule: To maintain the breeding numbers in Britain, Black-legged Kittiwakes Rissa tridactyla need to produce a mean of 0.8–1.5 fledged young per year.

Aims: To obtain a new estimate for the number of young Kittiwakes fledged per pair required to maintain breeding numbers in Britain in the period 1985–2015 based on field data.

Methods: The annual values of productivity in the River Tyne area of northeast England are compared with the long-term increases in numbers of breeding pairs in that area. Regressions between the annual productivity and the corresponding change in breeding numbers at 12 sites in Britain are used for the periods 1985–2000 and 15 sites for 2000–15.

Results: A long series of records of the annual productivity of Kittiwakes, where breeding pairs increased progressively over 61 years, showed that an annual productivity of 1.5 young fledged per pair was an extremely rare event. Over the periods 1985–2000 and 2000–15 regressions of the change in breeding numbers against mean annual productivity for 15 sites indicated that about 0.8 fledglings per pair were needed to maintain breeding numbers and this value remained unchanged over the 30 years, suggesting that adult mortality rates had not changed over this period of time.

Conclusion: The decline of Kittiwakes in Britain has occurred because fewer than 0.8 chicks per pair have been fledged at many sites in recent years. The mortality rate of adult Kittiwakes breeding in Britain 1985–2015 does not indicate an increase over time and so is unlikely to have been a major contributor to the decline in breeding numbers.     

Adult survival of Black-legged Kittiwakes Rissa tridactyla in a Pacific colony

Breeding Black-legged Kittiwakes Rissa tridactyla survived at a mean annual rate of 0.926 in four years at a colony in Alaska. Survival rates observed in sexed males (0.930) and females (0.937) did not differ significantly. The rate of return among nonbreeding Kittiwakes (0.839) was lower than that of known breeders, presumably because more nonbreeders moved away from the study plots where they were marked. Individual nonbreeders frequented sites up to 5 km apart on the same island, while a few established breeders moved up to 2.5 km between years. Mate retention in breeding Kittiwakes averaged 69% in three years. Among pairs that split, the cause of changing mates was about equally divided between death (46%) and divorce (54%). Average adult life expectancy was estimated at 13.0 years. Combined with annual productivity averaging 0.17 chick per nest, the observed survival was insufficient for maintaining population size. Rather, an irregular decline observed in the study colony since 1981 is consistent with the model of a closed population with little or no recruitment. Compared to their Atlantic counterparts, Pacific Kittiwakes have low productivity and high survival. The question arises whether differences reflect phenotypic plasticity or genetically determined variation in population parameters.     

The energy economy of the arctic-breeding Kittiwake (Rissa tridactyla): a review

The present paper reviews recent studies on changes in body mass, body composition and rates of energy expenditure during the breeding season in the black-legged Kittiwake (Rissa tridactyla) on Svalbard (79 degrees N). The main characteristic of the energy budget is a pronounced decrease in body mass as well as basal metabolic rate (BMR) after the eggs have hatched. While most internal organs lose mass in direct proportion to the general decrease in body mass, the liver and kidney masses decrease to a disproportionately greater extent. Since both the liver and the kidney have high intrinsic metabolic rates, these results support an earlier notion that the reduction in body mass is an adaptation to reduce maintenance costs. Alternatively, the reduced BMR is due to a decrease in energy uptake from the gastrointestinal tract, thereby ensuring that undigested food is ready to be regurgitated to the chicks. At the end of the chick-rearing period, the field metabolic rate (FMR) reaches its highest level, probably due to an increased workload associated with chick feeding. This occurs at a time of low body mass and BMR. A pronounced increase in the metabolic scope (FMR/BMR) during the latter part of the chick-rearing period demonstrates that BMR and FMR may change independently of each other and that the ratio FMR/BMR may not be a good measure of energy stress.     

Individual Vocal Recognition in the Kittiwake Gull,Rissa tridactyla (L.)

Breeding Kittiwake Gulls recognized their partners by voice alone. The voices of all individuals in the population showed consistent differences in their tonal and temporal structures. The role of calling behaviour in a cliff-nesting context is discussed.     

Parental attendance and squatting in the Kittiwake Rissa tridactyla during the rearing period

Parental attendance was studied in 1991 in the Cap Sizun Kittiwake colonies (Brittany, France). After a period of continuous guarding lasting on average 22 days, parents left their chicks unattended. Thereafter, parental attendance decreased regularly until fledging. The chick age when first left alone was on average 3 days lower for large broods than for single-chick broods. Moreover, whatever the brood size, chicks from late nests were younger when left unattended. Parental age affected the initiation of first absence. Younger parents reduced their attendance sooner than older parents. About 80% of the nests with chicks were visited by other adults at least once during the absence of the parents, and 50% were visited in the 3 days following the first absence of the breeders. These squatters were mainly failed breeders and prebreeders looking for a future breeding site. The results are discussed in terms of costs and benefits of chick neglect and comparisons were made with data from other studies in North Atlantic and Alaskan colonies. This reflected the flexibility of adult behaviour in relation to brood size and food availability.     

The influence of pair-status on the breeding behaviour of the Kittiwake Rissa tridactyla before egg-laying

The breeding behaviour of individually marked Kittiwakes Rissa tridactyla that retained mates from the previous year (SAME) was compared, over the period from pair-formation to egg-laying, with those that changed mates (CHANGE). Position of nest-site in colony and breeding experience did not differ in the two groups studied. Hirds in CHANGE pairs attended the nest-site more frequently and as a result probably had less 'off-duty' time during which to forage. Rates of greeting were higher in CHANGE pairs. Differences between the two groups were usually greatest during the first two weeks after pair-formation an decreased toward egg-laying. CHANGE pairs copulated over a longer period before egg- laying, but stopped copulating sooner than SAME pairs. Copulation rates were higher in SAME pairs immediately before egg-laying. The causation of the behavioural differences between the two groups is discussed in terms of mate familiarity. It is suggested that the recorded differences explain the lower reproductive success in CHANGE pairs reported by other workers.     

Attendance off breeders and prospectors reflects the quality off colonies in the Kittiwake Rissa tridactyla

Attendance of breeders and prospectors (prebreeders, failed breeders and non-breeding adults) was studied from the time of hatching to the end of the breeding season in parts of two neighbouring Kittiwake Rissa tridactyla colonies in Brittany (France). Many clutches in one subcolony had been predated by a Carrion Crow Corvus corone , leading to a lower breeding success. Attendance of breeders and prospecting activity were greater in the more successful colony, and the number of breeding pairs increased in the following year in this colony only. Local reproductive success and social behaviour contributed to the attraction exerted by a colony. The demographic trend was explained by a performance-based conspecific attraction mechanism, acting through the effect of local reproductive success on recruitment, non-breeding and fidelity. Study of breeding success and prospecting activity allowed both evaluation of the quality of a colony and prediction of local demographic trends for the following year.     

Breeding ecology of the Fulmar Fulmarus glacialis and the Kittiwake Rissa tridactyla in high-arctic northeastern Greenland, 1993

The breeding ecology of the Fulmar Fulmarus glacialis and the Kittiwake Rissa tridactyla in the high Arctic was studied in relation to the occurrence of the northeast water polynya in northeasternmost Greenland (80̀N). Mean laying dates were 31 May in the Fulmar and 18 June in the Kittiwake; the total nesting season for the Fulmar just matched the time window of the polynya opening period. Fulmar colony attendance fluctuated within a period of 11.6 days because of variation in nonbreeding prospectors but showed no clear diurnal variation. Fulmar incubation shifts, on average, lasted 6.1 days (range 1–13 days), which is significantly longer than elsewhere, and the average chick-guard period of 10.9 days (range 1–17 days) was significantly shorter than in other studies. Egg neglect occurred in 18% of Fulmar nests or 0.7% of nests per day. Overall breeding success (chicks fledged per egg laid) was 0.56 in the Fulmar and 0.67 in the Kittiwake; the latter produced 1.4 young per active nest or 1.2 per completed nest. Mean Kittiwake clutch size was 2.03; larger clutches were laid early. Nest site characteristics (presumably reflecting nest predation risk) and breeding behaviour affected breeding success. in the Fulmar, hatching success was negatively correlated with laying date and the proportion of egg neglect, while overall breeding success was correlated negatively with distance to nearest neighbouring site and positively with the length of the chick-guard period. Kittiwake breeding success was negatively correlated with laying date. Using seabirds as indicators of marine food supply, breeding success in both species suggested moderate to good food supply in the northeast water polynya in 1993, although at least in the Fulmar the high reproductive output appeared partly maintained by behavioural buffering; long incubation shifts, egg neglect and short chick-guard periods were symptoms of foraging constraints.     

Reproductive success of the Kittiwake Rissa tridactyla: the roles of clutch size, chick growth rates and parental quality

Kittiwake growth rates and breeding success are examined in relation to survival between fledging and breeding and to adult survival rates. High chick growth rates lead to increased survival after fledging. Broods of three (the maximum brood size) did not suffer lower fledging success than broods of two and clutches of three fledged appreciably more chicks per pair than did clutches of two or one. On average, the a- and b -chicks in broods of three grew at a faster rate and had a higher survival before breeding than those from smaller broods. Chicks from broods of two with experienced female parents grew at a faster rate than those of inexperienced female parents. Female parents which laid three egg clutches had a higher survival rate than those which laid clutches of two or one. We contend that three egg clutches were laid by higher quality individuals. We believe that clutch size indicates the condition of the Kittiwakes forming the pair. This condition probably has a genetical component, but is modified by environmental factors.     

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.     

Individual variation in field metabolic rate of kittiwakes (Rissa tridactyla) during the chick-rearing period

Field metabolic rate (FMR), using the doubly labelled water (DLW) method, was measured in free-ranging adult kittiwakes (Rissa tridactyla) early and late in the chick-rearing period at Svalbard, Norway. Individual variation in FMR was analysed by comparing FMR with body mass, sex, nest attendance, chick age, brood size, and basal metabolic rate (BMR). Mean FMR of kittiwakes during the chick-rearing period was 27.0+/-0.9 (SE) W kg(-1), while the individual variation (calculated as coefficient of variation [CV]) in FMR was 24%. Sex, time spent away from the nest, age of the chicks, and brood size contributed significantly to FMR and explained 65% of the variation in FMR. The FMR increased by 32% from early until late in the chick-rearing period. This occurred simultaneously with an increase in the time spent away from the nest. In 15 of 20 pairs, one of the mates had 15% or higher (mean of the 15 pairs, 22%+/-8%) FMR (W kg(-1)) than their partner, even though the mates spent equal amounts of time away from the nest. This indicates an intrapair conflict in FMR. The variation in total FMR of pairs was 40% less than the individual variation, and total FMR of pairs increased with age of the chicks. This indicates that the mates adjust their energy expenditure within a relatively constant FMR determined by the energy needs of the chicks. Individual variation in FMR could not be explained by variation in body mass or BMR. BMR measured late in the chick-rearing period was 26% lower than previous measurements of BMR from the prebreeding and incubation periods. The increase in FMR and simultaneous decrease in BMR caused a 40% increase in metabolic intensity (FMR/BMR) of kittiwakes during the chick-rearing period. It is suggested that the metabolic intensity is not a proper measure of the metabolic load in seabirds.     

The incidence of the tick parasite Ixodes uriae in Kittiwake Rissa tridactyla colonies in relation to the age of the colony, and a mechanism of infecting new colonies

Kittiwakes Rissa tridactyla (683 chicks and 64 adults) were examined for ectoparasites in three breeding areas: Isle of May (Firth of Forth, Scotland; eight colonies of approximately known age of occupation on natural sites), North Shields and Gateshead (Tyne and Wear, England; well established colonies of known age on buildings). All the 208 ticks collected were Ixodes uriae. On the Isle of May, a colony which had only been established for 7 years was already infested by ticks. Tick incidence increased significantly with the length of colonization of the area during the first 30 years. Age of colonization did not have an effect after 30 years. In Gateshead only a single adult among the 127 birds examined had a tick. No ticks were found on the 106 chicks born at North Shields checked in 1987 or in 1988. However, among nine visiting newly-fledged chicks from neighbouring colonies caught at the North Shields colony, six had either ticks or scars of previous infestation. Some visiting chicks remained for several days in the host colony and were even fed by the owners of visited nests. Ixodes uriae may thus spread from one colony to another during visits of newly-fledged infested chicks to neighbouring colonies. The absence of any infestation in old colonies (38 years in North Shields and 17 years in Gateshead) on buildings that are regularly visited by newly fledged infested chicks, suggests that buildings may lack the rock refuges necessary for tick survival from one year to the next. In this respect Kittiwake colonies on buildings are rather atypical.     

Comparative host-parasite population structures: disentangling prospecting and dispersal in the black-legged kittiwake Rissa tridactyla

Although much insight is to be gained through the comparison of the population genetic structures of parasites and hosts, there are, at present, few studies that take advantage of the information on vertebrate life histories available through the consideration of their parasites. Here, we examined the genetic structure of a colonial seabird, the black-legged kittiwake (Rissa tridactyla) using seven polymorphic microsatellite markers to make inferences about population functioning and intercolony dispersal. We sampled kittiwakes from 22 colonies across the species' range and, at the same time, collected individuals of one of its common ectoparasites, the tick Ixodes uriae. Parasites were genotyped at eight microsatellite markers and the population genetic structure of host and parasite were compared. Kittiwake populations are only genetically structured at large spatial scales and show weak patterns of isolation by distance. This may be due to long-distance dispersal events that erase local patterns of population subdivision. However, important additional information is gained by comparing results with those of the parasite. In particular, tick populations are strongly structured at regional scales and show a stepping-stone pattern of gene flow. Due to the parasite's life history, its population structure is directly linked to the frequency and spatial extent of within-breeding season movements of kittiwakes. The comparison of host and parasite gene flow therefore helps us to disentangle the intercolony movements of birds from that of true dispersal events (movement followed by reproduction). In addition, such data can provide essential elements for predicting the outcome of local co-evolutionary interactions.     

The influence of food supply on the breeding ecology of Kittiwakes Rissa tridactyla in Shetland

We measured the breeding performance, body condition, time budgets and foraging ranges of Kittiwakes Rissa tridactyla at Sumburgh Head, Shetland, in two years of contrasting food availability. Kittiwakes in Shetland generally feed their young almost entirely on sandeels, and fisheries data indicated that stocks of sandeels in Shetland waters were at least ten times higher in 1991 than in 1990. Fledging success of Kittiwakes was nil in 1990 and 68% of eggs laid in 1991, although clutch-size and hatching success were no different between years. Post-hatching foraging trips in 1991 were of comparable duration to those recorded at other colonies in conditions of good food supply (2–3 h), while trips recorded during incubation or post-hatching in 1990 were approximately three times longer on average than at corresponding stages of the breeding season in 1991. Radio-tracking data indicated that adults generally stayed within 5 km of the colony in 1991 but flew more than 40 km from the colony on each trip in 1990. Eggs were apparently not left unattended in either year, despite the fact that this required adults to incubate for periods in excess of 44 h in 1990. The extent to which adults were able to increase trip durations, foraging ranges and incubation shift lengths between years, while maintaining hatching success, indicates the degree to which Kittiwakes are normally buffered against adverse feeding conditions during incubation. Reduced nest attendance and lower body-condition of adults post-hatching in 1990, in conjunction with complete post-hatching breeding failure, indicate that adults were beyond the limits of their buffering capacity during chick-rearing in 1990.     

Seasonal interactions in the black-legged kittiwake, Rissa tridactyla: links between breeding performance and winter distribution

Relationships between events in one period of the annual cycle and behaviour in subsequent seasons are key determinants of individual life histories and population dynamics. However, studying such associations is challenging, given the difficulties in following individuals across seasons, particularly in migratory species. Relationships between breeding performance and subsequent winter ecology are particularly poorly understood, yet are likely to be profoundly important because of the costs of reproduction. Using geolocation technology, we show that black-legged kittiwakes that experienced breeding failure left their colony in southeast Scotland earlier than successful breeders. Moreover, a greater proportion of unsuccessful breeders (94% versus 53% successful) travelled over 3000 km to the West Atlantic, whereas fewer visited the East Atlantic (31% versus 80% successful), less than 1000 km from the colony. The two groups did not differ in the timing of return to the colony the following spring. However, 58 per cent of males made a previously undescribed long-distance pre-breeding movement to the central Atlantic. Our results demonstrate important links between reproductive performance and winter distribution, with significant implications for population dynamics. Furthermore, macro-scale segregation associated with breeding outcome is relevant to defining important wintering areas, in particular among declining species experiencing increasingly regular breeding failure.     

Natural attachment duration of nymphs of the tick Ixodes uriae (Acari: Ixodidae) on kittiwake Rissa tridactyla nestlings

Daily searches of the plumage of 62 kittiwake (Rissa tridactyla) chicks were carried out for 3 weeks to determine the attachment duration of the tick Ixodes uriae. All ticks recorded were nymphs and their mean duration of attachment was 5.2±1.7 days (n=93). Seventy-four per cent of the ticks survived to engorgement and were assumed to have fed successfully. The mean duration of attachment of successful ticks was 5.8±1.0 days (n=69), significantly longer than that of unsuccessful ticks (3.3±2.1 days, n=24). There was no difference in survival rates to engorgement between ticks attached to feathered and unfeathered parts of the body (78.3 and 79.2%, respectively), but the duration of attachment of successful ticks was significantly longer on unfeathered compared to feathered areas. There were no significant differences in the survival to engorgement or duration of attachment between ticks found on young (c.11 days) and old (>11 days) kittiwake nestlings. The attachment duration was not related to the total number of ticks found on the host or the number of ticks present in the immediate vicinity of the site of attachment. This work provides important data on the parameter of attachment durations of nymphal I. uriae on free-living kittiwakes; the data can be used for incorporation into the application of population modelling.     

Induced maternal response to the Lyme disease spirochaete Borrelia burgdorferi sensu lato in a colonial seabird, the kittiwake Rissa tridactyla

Mothers are predicted to invest in their offspring depending on the quality of their mate, their opportunity to invest in future reproduction and the characteristics of the habitat in which their offspring will be born. Recent studies have suggested a transfer of maternal immunity to offspring as an induced response to the local presence of parasites in the environment, but evidence has been indirect. Here, we show the presence of antibodies against the Lyme disease agent Borrelia burgdorferi sensu lato, a spirochaete transmitted by the seabird tick Ixodes uriae, in the eggs of kittiwakes Rissa tridactyla. We report higher prevalence of antibodies against Borrelia in eggs from breeding areas with higher prevalence and abundance of ticks. Further, high repeatabilities of antibody-positive eggs within clutches and between first and replacement clutches show that, within a breeding season, females differ consistently with respect to the expression of this induced maternal response. Our results suggest that mothers can alter investment in their young depending on local conditions. Such maternal effects clearly have implications for the ecology and evolution of host-parasite interactions.     

The behaviour associated with the occupation of breeding site in the kittiwake gull Rissa tridactyla: the social status of landing birds

A study of the landings of individually colour-ringed kittiwakes at nest sites showed that two functionally distinct categories of pre-and post-landing behaviour were adopted according to the social status (owner versus non-owner) of the landing bird with regard to the site in question. Almost all the occurrences where the behaviour of the adult was inconsistent with its social status were either due to a progressive development (or challenging) of the bird's status with respect to the landing site (56 cases), or the result of a conflicting situation (three cases). A diagram summarizing the behavioural stages in the ontogenetic process of acquiring site owner status (a fundamental stage in attaining breeding status) was established. It includes all the inconsistent situations observed. This shows that at every stage of the process the birds have different roles in the elaboration of the social environment of the colony.     

Acoustic communication in the Kittiwake <Emphasis Type="Italic">Rissa tridactyla</Emphasis>: potential cues for sexual and individual signatures in long calls

Sex and individual recognition systems vary among species and can have various functions in different contexts. In order to determine the basis of identification by voice in the Kittiwake (Rissa tridactyla), the greeting calls of 32 individuals (18 males and 14 females) were recorded in May–June 2004 on the Kittiwake colony of Hornøya island (Barents sea) and analysed. On the basis of coefficient of variation calculations and discriminant analyses, we show (1) that calls are sexually dimorphic and that the dimorphism is mainly based on the value of the fundamental frequency, and (2) that calls are individually distinct, individuality being due to a complex of temporal and frequency parameters located in different parts of the signal. This coding strategy is discussed in the context of the colonial breeding habitat of the species.     

Role of resting metabolic rate and energy expenditure in hunger and appetite control: a new formulation

A long-running issue in appetite research concerns the influence of energy expenditure on energy intake. More than 50 years ago, Otto G. Edholm proposed that “the differences between the intakes of food [of individuals] must originate in differences in the expenditure of energy”. However, a relationship between energy expenditure and energy intake within any one day could not be found, although there was a correlation over 2 weeks. This issue was never resolved before interest in integrative biology was replaced by molecular biochemistry. Using a psychobiological approach, we have studied appetite control in an energy balance framework using a multi-level experimental system on a single cohort of overweight and obese human subjects. This has disclosed relationships between variables in the domains of body composition [fat-free mass (FFM), fat mass (FM)], metabolism, gastrointestinal hormones, hunger and energy intake. In this Commentary, we review our own and other data, and discuss a new formulation whereby appetite control and energy intake are regulated by energy expenditure. Specifically, we propose that FFM (the largest contributor to resting metabolic rate), but not body mass index or FM, is closely associated with self-determined meal size and daily energy intake. This formulation has implications for understanding weight regulation and the management of obesity.