Topic
Booby
About: Booby is a research topic. Over the lifetime, 275 publications have been published within this topic receiving 6395 citations. The topic is also known as: Booby.
Papers published on a yearly basis
Papers
TL;DR: Differences in published cost-of-flight values support the hypothesis that energetic competition determines flock structure at the low-productivity end of the system, and Sooty Terns have the lowest flight costs and feed in waters of lowest productivity.
Abstract: The oceanic eastern tropical Pacific supports a speciose seabird community that feeds in flocks and depends for food on schools of tunas and dolphins, which force prey to the surface. We analyzed data collected throughout an area of 40 3 10 6 km 2 of open ocean over 10 years (1979-1988) during 1136 at-sea days, from 1750 feeding flocks comprising 51 688 birds of 49 species. A PCA identified three distinct flock types based on species composition: ''Sooty Tern Flocks'' ( n 5 941 flocks) with a large number of Sooty Terns (Sterna fuscata), ''Juan-Wedge Flocks'' ( n 5 402 flocks) with a large number of Juan Fernandez Petrels (Pterodroma externa) and Wedge-tailed Shearwaters (Puffinus pacificus ), and ''Booby Flocks'' ( n 5 407 flocks) with a large number of Red-footed and Masked Boobies (Sula sula and S. dactylatra, respectively). Flock types exhibited largely disjunct distributions that mirrored patterns in thermocline depth and surface water chlo- rophyll content. Sooty Tern Flocks occurred in areas with deepest thermocline (77.6 m) and lowest chlorophyll (0.14 mg/m 3 ), Juan-Wedge Flocks in areas of intermediate ther- mocline (68.8 m) and chlorophyll (0.16 mg/m 3 ), and Booby Flocks in areas of shallowest thermocline (62.5 m) and highest chlorophyll (0.17 mg/m 3 ). These differences were sta- tistically significant. As thermocline depth and surface water chlorophyll are reliable in- dicators of surface water productivity, we conclude that Sooty Tern Flocks foraged in waters of low productivity, Juan-Wedge Flocks in waters of intermediate productivity, and Booby Flocks in waters of highest productivity. Differences in published cost-of-flight values support the hypothesis that energetic con- straint determines flock structure at the low-productivity end of the system. Sooty Terns have the lowest flight costs (4.8 W) and feed in waters of lowest productivity. Flight costs are progressively higher for those species feeding in more productive waters (9.9 W for Wedge-tailed Shearwaters, 19.0 W for Red-footed Boobies). Differences in body size sup- port the hypothesis that interference competition determines flock structure at the high- productivity end of the system. The largest species, Masked Boobies (1987 g) and Red- footed Boobies (1003 g), feed in areas of highest productivity; progressively smaller species, Juan Fernandez Petrels (430 g) and Wedge-tailed Shearwaters (388 g), and Sooty Terns (180 g), feed in areas of decreasing productivity. We hypothesize that this community is largely structured by two factors, competition and energetic constraint, that operate at opposite ends of a productivity gradient. As productivity decreases (low prey abundance), flight proficiency is increasingly important because only species with relatively low flight costs will be able to transit between prey patches. As productivity increases (high prey abundance), competitive ability is increasingly important because competitive dominants will exclude other species from feeding flocks. Our hypothesis is in accordance with em- pirical data and theoretical models designed to explain factors structuring communities for a wide variety of habitats and taxa.
252 citations
TL;DR: The breeding cycles and related biology of the White Boorby Sula dactylatra and the Brown Booby S. leucogaster at Ascension were investigated between November 1957 and April 1959 as discussed by the authors.
Abstract: SUMMARY
The breeding cycles and related biology of the White Boorby Sula dactylatra and the Brown Booby S. leucogaster at Ascension were investigated between November 1957 and April 1959.
In both species there were marked peaks of laying, with intervening periods of very few new clutches. In the White Booby, although only one full season was studied, an annual cycle was deduced; in the Brown Booby (two full seasons) the cycle appeared to be eight-monthly. The breeding season (laying of eggs to fledging of chicks) was however roughly the same length in both species, namely six to seven months. Individuals of both species for the most part conformed to the breeding seasons of the population as a whole, i.e. if out of phase for some reason, had a longer or shorter “rest” period as necessary to bring them into phase again for the next season. These discoveries indicate that external factors are controlling the times of breeding. The proximate factors are not known; at Ascension there is no appreciable seasonal variation in day-length or climate, and possible cycles in the surrounding sea could not be investigated.
The two species' periodicity was such that, if maintained, every two years they would lay at almost the same time of year, July–August. The possible relation of these observations to a single underlying factor, perhaps annual variation in oceanic conditions with their origin in the seasonal melting of the Antarctic ice and consequent effect on the food cycles, is discussed.
Details of incubation, desertion, feeding, care and growth of the chick are given. The regular death of the second chick as a result of asynchronous hatching, and experiments with twins are described. A low breeding-success, and deaths of chicks from starvation, indicated that both species suffered a shortage of food over an ill-defined period around August-September 1958. Regurgitations of food examined throughout the study, and a few observations on feeding, indicated a big overlap in the two species' diets, mainly flying-fish, but some differences did appear.
Details of moult, mainly in the White Booby, are given. Shedding and re-growth of the juvenile primaries began at about seven months of age, proceeding from the innermost outwards in three spaced concurrent cycles, this remarkable pattern continuing throughout adult life. A period of pause in the primary moult was correlated with the time when most birds had chicks, but some birds were known to be moulting their primaries while breeding. A prolonged moult with a pause during breeding was indicated by examination of some other Ascension species; the relevance of this to the availability of food and breeding seasons in tropical sea-birds is discussed.
221 citations
TL;DR: It is shown that analyzing stable isotope values in blood and feathers appears to be a promising alternative method for investigating food and feeding ecology of tropical seabirds year round, and for determin- ing sex- and age-related differences in their foraging strategies.
Abstract: Characteristics of the tropical oceanic environment (low productivity, little seasonality) and poor diversity of tropical seabird foraging methods and prey relative to temperate and polar spe- cies suggest that tropical seabirds overall encompass a narrow range of isotopic niches, with large overlaps among species. To test this hypothesis, we examined the stable carbon (δ 13 C) and nitrogen (δ 15 N) isotopic composition of blood and feathers of 5 seabird species from Europa Island, Mozam- bique Channel. While differences were small, blood δ 13 C and δ 15 N values characterized 5 distinct and non-overlapping trophic niches during the breeding period. Seabirds used 2 distinct foraging areas (δ 13 C), one used by sooty tern Sterna fuscata and white-tailed tropicbird Phaethon lepturus and one used by red-footed booby Sula sula and great Fregata minor and lesser F. ariel frigatebirds. Seabird species overall encompassed less than 1 trophic level (δ 15 N), which is in agreement with a diet mainly based on flying fish and squid. Feather δ 13 C and δ 15 N values showed that the trophic structure of the community was different during the breeding and non-breeding (moulting) periods, suggesting a shift in the feeding ecology when adult birds were no longer central-place foragers. The stable iso- tope method underlined sex-related (red-footed booby) and age-related (great frigatebird immatures and adults) feeding strategies. It also suggested that breeding adults could feed themselves on differ- ent prey than those given to their chicks (sooty tern). Within the tropical pelagic ecosystem, seabirds overall shared the same trophic level as large predatory fishes (albacore, yellowfin and skipjack tunas), but they had lower δ 15 N values than the deeper-dwelling bigeye tuna and swordfish. We con- clude that analyzing stable isotope values in blood and feathers appears to be a promising alternative method for investigating food and feeding ecology of tropical seabirds year round, and for determin- ing sex- and age-related differences in their foraging strategies. A limitation of the method is the lack of information on marine isoscapes; future studies aimed at isotopically characterizing the tropical marine environment could help to associate consumer signatures to geographic origins.
178 citations
TL;DR: Because of the chick’s slow growth and reduced daily need for food, brooding in Red-footed Boobies may not require a marked increase in parental effort, and the rise in corticosterone levels is probably more a reflection of slight changes in foraging activity.
Abstract: Plasma levels of corticosterone often mirror changes in body condition and parental effort. In seabirds, the brooding of young chicks is often paralleled by a marked decline in adult body condition. This may reflect the trade-off between the needs of the chick to be fed regularly and brooded, and that of the adult to spend enough time at sea to restore its body reserves and find food for the chick. In this paper, we describe changes in body condition and baseline corticosterone levels in a tropical seabird, the Red-footed Booby Sula sula , in which the chick is continuously brooded for 5‐6 weeks. Body condition did not decline during the brooding period. Female body condition remained stable throughout breeding whereas male body condition declined significantly during the late chick-rearing period. Baseline corticosterone levels were low during the prelaying phase, increased significantly during incubation and were highest during the brooding period. Later in the chick-rearing period, baseline corticosterone levels decreased markedly in females, but stayed elevated in males. There was no correlation between baseline corticosterone and body condition. Because of the chick’s slow growth and reduced daily need for food, brooding in Red-footed Boobies may not require a marked increase in parental effort, and the rise in corticosterone levels is probably more a reflection of slight changes in foraging activity. Red-footed Booby males are 15% smaller than females and we suggest that the decline in male body condition during the late chick-rearing period is likely to result from higher energetic flight costs or a lower foraging efficiency imposed by a smaller body size.
168 citations
TL;DR: The data indicate that blue-footed booby females are continuously evaluating their mates and can perform rapid adjustments of reproductive investment by using dynamic sexual traits, and suggests that this fine-tuned adjustment may be widespread in socially monogamous animals.
Abstract: In monogamous species, the value of present reproduction is affected by the current condition of the mate, and females may use male ornaments to evaluate his condition and adjust their level of investment according. Many animals display colour in fleshy structures which may be accurate indicators of quality due to their potentially rapid response to changes in condition. Here we show that in the blue-footed booby, Sula nebouxii, male foot colour is structurally (collagen arrays) and pigment based. In 48 h foot colour became duller when males were food deprived and brighter when they were re-fed with fresh fish. Variation of dietary carotenoids induced comparable changes in cell-mediated immune function and foot colour, suggesting that carotenoid-pigmentation reveals the immunological state of individuals. These results suggest that pigment-based foot colour is a rapid honest signal of current condition. In a second experiment, we found that rapid variation in male foot colour caused parallel variation in female reproductive investment. One day after the first egg was laid we captured the males and modified the foot colour of experimental males with a non-toxic and water resistant duller blue intensive make-up, mimicking males in low condition. Females decreased the size of their second eggs, relative to the second egg of control females, when the feet of their mates were experimentally duller. Since brood reduction in this species is related to size differences between brood mates at hatching, by laying lighter second eggs females are facilitating brood reduction. Our data indicate that blue-footed booby females are continuously evaluating their mates and can perform rapid adjustments of reproductive investment by using dynamic sexual traits. We suggest that this fine-tuned adjustment may be widespread in socially monogamous animals.
168 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 10 |
| 2020 | 10 |
| 2019 | 3 |
| 2018 | 10 |
| 2017 | 16 |
| 2016 | 13 |