Added: Sabastian Howe - Date: 27.02.2022 04:39 - Views: 18367 - Clicks: 8514
With a personalyou can read up to articles each month for free. Already have an ? Log in. Log in through your institution. The study was conducted from early May to early August on a 1. All breeding spotted sandpipers were colour-ringed. Time budgets were determined for 10 females and 23 males by instantaneous sampling at second intervals of 10 predetermined behaviours.
A total of 1, minute samples 2 birds each yieldeddata points when birds were visible. Terrestrial arthropod abundance was sampled by cylindrical sticky traps at 12 locations for 48 hours per week. Temperature, wind direction and velocity, and cloud cover were recorded at the time instantaneous samples were conducted. Basal metabolic rates were calculated separately for each sex as a function of body weight. Energy budgets were estimated by extrapolation from time budgets.
Caloric and calcium content of principal food items and sandpiper eggs was determined with a Parr adiabatic oxygen calorimeter and a Perkin-Elmer atomic absorption spectrophotometer. During prelaying, females foraged more than males, preened less and flew less. During laying, females foraged, rested, and engaged in agonistic activity more than males. Males spent more time preening, flying, nest building and incubating than their mates. All behaviours differed between sexes during incubation as females spent more time than males in all activities except nest building and incubation.
Sex differences were the result of differential strategies to maximize reproductive success and differing energy requirements due to size dimorphism and the energy costs of egg production. Time spent in all behaviours varied among stages of the breeding cycle due primarily to changes in foraging and incubation requirements. Foraging varied by time of day but the pattern of this variation changed among stages of the breeding cycle due principally breeding season 7.8 diurnal variation in incubation and brooding time.
With the exception of the incubation period when only breeding season 7.8 and agonistic behaviour did not vary diurnally, most behaviours did not show diurnal variation.
When females helped their mates, nests were incubated a greater proportion of the time than when males incubated alone. Terrestrial arthropod abundance exhibited 2 major peaks each year about 4 weeks apart. Each year a different territory produced the most food over the season as a whole.
Time budgets varied among clutches, among territories, and among years but these differences were largely explicable by changes in food abundance. Food abundance consistently influenced foraging time for both sexes. Other activities correlated less consistently with food abundance. Decreases in foraging time, due to higher food levels, were compensated for primarily by increasing time spent in maintenance activities. Temperature, wind, and cloud cover had less influence on time budgets than food abundance, especially for females.
Eggs averaged 5. Each egg cost a female For activities other than egg formation, foraging received the most energy expenditure during all stages of the breeding cycle except for males during incubation. Both sexes had minimal DEE's during the incubation period. A clutch of 4 eggs totaled 1. Analysis of principal food items indicated that it was unlikely that females totally relied on these organisms as a calcium source.
Energy expended in foraging was typically lower during periods of food abundance than periods of food scarcity. DEE usually increased as food changed from abundant to scarce. Required foraging efficiencies RFE decreased as food abundance decreased, indicating that birds had to expend greater amounts of energy to obtain a given quantity of food as food levels dropped. For polyandry to evolve, males must assume most or all of the parental duties. A female can produce replacement clutches faster if freed from incubation duties, as this allows her more time to forage.
Once male parental care has evolved, sequential polyandry can readily evolve where fewer replacement clutches are required e. Behaviour publishes breeding season 7.8 research pursuing Tinbergen's four questions and questions resulting from the interrelationship among the four. In addition, the editorial board encourages reviews of behavioural biology that illuminate emergent trends and new directions in behavioural research.
Niko Tinbergen defined 4 questions for research in behavioral biology: Proximate causation of behaviour: 1. How does an animal use its sensory and motor abilities to activate and modify its behaviour patterns? How does an animal's behaviour change during its growth, especially in response to the experiences that it has while maturing?
How does the behaviour promote an animal's ability to breeding season 7.8 and reproduce? How does an animal's behaviour compare with that of other closely related species, and what does this tell us about the origins of its behavior and the changes that have occurred during the history of the species? Tinbergen was at heart an experimentalist who, more than Lorenz and von Frisch, applied the scientific method to the field of animal and human behaviour.
It is his experimental approach to the study of behaviour that lasts to this day. That is why Tinbergen listed questions and not answers theorems or laws. The answers or at least some of them are published monthly in Behaviour, the journal Tinbergen co-founded with W.
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Abstract The study was conducted from early May to early August on a 1. Journal Information Behaviour publishes original research pursuing Tinbergen's four questions and questions resulting from the interrelationship among the four.Breeding season 7.8
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Ovarian function in ewes during the transition from breeding season to anoestrus