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Joel Bety - One of the best experts on this subject based on the ideXlab platform.
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77 © WILDLIFE BIOLOGY · 9:3 (2003) Effects of collar-attached transmitters on behaviour, pair bond and breeding success of snow geese Anser caerulescens atlanticus
2016Co-Authors: Frederic Demers, Jeanfrancois Giroux, Gilles Gauthier, Joel BetyAbstract:transmitters on behaviour, pair bond and breeding success of snow geese Anser caerulescens atlanticus.- Wildl. Biol. 9: 77-86. There is growing evidence that harnesses may not be an effective technique to attach radio-transmitters on geese. The use of neck collars is an alternative, but studies on the effect of collars with or without radios on geese have reached divergent conclusions. As our objective was to determine if radio neck collars affect behaviour, pair bonds and breeding success of greater snow geese Anser caerulescens atlanticus, we fitted 230 females with radio neck collars during the 1995-1998 moulting periods on Bylot Island, Nunavut. Data were subse-quently obtained for 159 birds on the staging and breeding grounds. Radios rep-resented 2.5 ± 0.1 % ( ± SE) of the birds’body mass. Unmarked geese and those fitted with conventional plastic collars served as controls. The behaviour of radio-collared geese was affected during the first fall after marking, but negative effects disappeared thereafter. Geese with conventional collars had similar behaviour as unmarked birds. Divorce rates were low for birds with conventional collars (0-4%), but were as great as 30 % for radio-collared geese. We suggest that the modified behaviour of the radio-collared females promoted separation from the male. Apparent breeding propensity, nest initiation date, clutch size and nest-ing success of radio-marked birds were also negatively affected. Until better alternatives are developed, we recommend minimizing the mass of radio col-lars to < 2.5 % of the birds ’ body mass and reducing the antenna length. This implies a trade-off between effects on birds and performance of the transmit-ters in terms of battery mass (longevity) and antenna length (range)
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benefiting from a migratory prey spatio temporal patterns in allochthonous subsidization of an arctic predator
Journal of Animal Ecology, 2012Co-Authors: Gilles Gauthier, Dominique Berteaux, Marieandree Giroux, Nicolas Lecomte, Guillaume Szor, Joel BetyAbstract:Summary 1. Flows of nutrients and energy across ecosystem boundaries have the potential to subsidize consumer populations and modify the dynamics of food webs, but how spatio-temporal variations in autochthonous and allochthonous resources affect consumers’ subsidization remains largely unexplored. 2. We studied spatio-temporal patterns in the allochthonous subsidization of a predator living in a relatively simple ecosystem. We worked on Bylot Island (Nunavut, Canada), where arctic foxes (Vulpes lagopus L.) feed preferentially on lemmings (Lemmus trimucronatus and Dicrostonyx groenlandicus Traill), and alternatively on colonial greater snow geese (Anser caerulescens atlanticus L.). Geese migrate annually from their wintering grounds (where they feed on farmlands and marshes) to the Canadian Arctic, thus generating a strong flow of nutrients and energy across ecosystem boundaries. 3. We examined the influence of spatial variations in availability of geese on the diet of fox cubs (2003–2005) and on fox reproductive output (1996–2005) during different phases of the lemming cycle. 4. Using stable isotope analysis and a simple statistical routine developed to analyse the outputs of a multisource mixing model (SIAR), we showed that the contribution of geese to the diet of arctic fox cubs decreased with distance from the goose colony. 5. The probability that a den was used for reproduction by foxes decreased with distance from the subsidized goose colony and increased with lemming abundance. When lemmings were highly abundant, the effect of distance from the colony disappeared. The goose colony thus generated a spatial patterning of reproduction probability of foxes, while the lemming cycle generated a strong temporal variation of reproduction probability of foxes. 6. This study shows how the input of energy owing to the large-scale migration of prey affects the functional and reproductive responses of an opportunistic consumer, and how this input is spatially and temporally modulated through the foraging behaviour of the consumer. Thus, perspectives of both landscape and foraging ecology are needed to fully resolve the effects of subsidies on animal demographic processes and population dynamics.
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climate trophic interactions density dependence and carry over effects on the population productivity of a migratory arctic herbivorous bird
Oikos, 2010Co-Authors: Manon Morrissette, Gilles Gauthier, Joel Bety, Austin Reed, Josee LefebvreAbstract:Several driving forces can aff ect recruitment rates in bird populations. However, our understanding of climate-induced eff ects or bottom–up vs top–down biological processes on breeding productivity typically comes from small-scale studies, and their relative importance is rarely investigated at the population level. Using a 31-year time series, we examined the eff ects of selected environmental parameters on the annual productivity of a key Arctic herbivore, the greater snow goose Anser caerulescens atlanticus. We determined the extent to which breeding productivity, defi ned as the percentage of juveniles in the fall population, was aff ected by 1) climatic conditions, 2) fl uctuations in predation pressure caused by small rodent oscillations, and 3) population size. Moreover, we took advantage of an unplanned large-scale manipulation (i.e. management action) to examine the potential non-lethal carry-over eff ects caused by disturbance on spring staging sites. Th e most parsimonious model explained 66% of the annual variation in goose productivity. Th e spring North Atlantic Oscillation and Arctic snow depth were the primary climatic parameters inversely aff ecting the production of juveniles, likely through bottom–up processes. Indirect trophic interactions generated by fl uctuations in lemming abundance explained 18% of the variation in goose productivity (positive relationship). Mean temperature during brood-rearing and disturbance on staging sites (carry-over eff ects) were the other important factors aff ecting population recruitment. We observed a strong population increase, and found no evidence of density-dependent eff ects. Spatially restricted studies can identify factors linking environmental parameters to local bird reproduction but if these factors do not act synchronously over the species range, they may fail to identify the relative importance of mechanisms driving large-scale population dynamics.
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Individual variation in timing of migration: causes and reproductive consequences in greater snow geese (Anser caerulescens atlanticus)
Behavioral Ecology and Sociobiology, 2004Co-Authors: Joel Bety, Jeanfrancois Giroux, Gilles GauthierAbstract:Decisions made by birds during migration to breeding grounds can strongly affect the fitness of individuals. We investigated possible causes and reproductive consequences of inter-individual variation in the migratory behavior of an arctic-nesting species, the greater snow goose ( Anser caerulescens atlanticus ), by radio-tracking females at their staging area and on their breeding grounds. Females showed relatively high repeatability in the duration of migration (r_i=0.37) and arrival date on the breeding grounds (r_i=0.42) suggesting that these traits are characteristics of individuals. Conversely, no individual consistency in departure date from the staging area was detected (r_i=−0.02) indicating that environmental factors may have a large influence. Females paired with dominant males departed slightly earlier from the staging area than females accompanied by subordinate males. However, neither social status on the staging area (i.e. paired vs unpaired) nor dominance scores were associated with arrival time of individuals. Finally, the probability of breeding was positively related to arrival date indicating a reproductive cost of arriving too early on the breeding grounds. The combination of breeding probability and seasonal decline in breeding success nonetheless suggests that females arriving a few days earlier than the median arrival date attained highest reproductive success. Our results show that assessing the fitness consequences of early arrival by focusing solely on breeding females would lead to an overestimation of the genuine benefits. This study also indicates possible genetically based differences among individuals in migration duration and arrival time on the breeding grounds.
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effects of collar attached transmitters on behaviour pair bond and breeding success of snow geese Anser caerulescens atlanticus
Wildlife Biology, 2003Co-Authors: Frederic Demers, Jeanfrancois Giroux, Gilles Gauthier, Joel BetyAbstract:There is growing evidence that harnesses may not be an effective technique to attach radio-transmitters on geese. The use of neck collars is an alternative, but studies on the effect of collars with or without radios on geese have reached divergent conclusions. As our objective was to determine if radio neck collars affect behaviour, pair bonds and breeding success of greater snow geese Anser caerulescens atlanticus, we fitted 230 females with radio neck collars during the 1995–1998 moulting periods on Bylot Island, Nunavut. Data were subsequently obtained for 159 birds on the staging and breeding grounds. Radios represented 2.5 ± 0.1 % (± SE) of the birds' body mass. Unmarked geese and those fitted with conventional plastic collars served as controls. The behaviour of radiocollared geese was affected during the first fall after marking, but negative effects disappeared thereafter. Geese with conventional collars had similar behaviour as unmarked birds. Divorce rates were low for birds with conventional c...
Gilles Gauthier - One of the best experts on this subject based on the ideXlab platform.
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the greater snow goose Anser caerulescens atlanticus managing an overabundant population
AMBIO: A Journal of the Human Environment, 2017Co-Authors: Josee Lefebvre, Jeanfrancois Giroux, Gilles Gauthier, Austin Reed, Eric T Reed, Luc BelangerAbstract:Between the early 1900s and the 1990s, the greater snow goose Anser caerulescens atlanticus population grew from 3000 individuals to more than 700 000. Because of concerns about Arctic degradation of natural habitats through overgrazing, a working group recommended the stabilization of the population. Declared overabundant in 1998, special management actions were then implemented in Canada and the United States. Meanwhile, a cost–benefit socioeconomic analysis was performed to set a target population size. Discussions aiming towards attaining a common vision were undertaken with stakeholders at multiple levels. The implemented measures have had varying success; but population size has been generally stable since 1999. To be effective and meet social acceptance, management actions must have a scientific basis, result from a consensus among stakeholders, and include an efficient monitoring programme. In this paper, historical changes in population size and management decisions along with past and current challenges encountered are discussed.
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Behav Ecol Sociobiol (2004) 57:1–8 DOI 10.1007/s00265-004-0840-3
2016Co-Authors: Gilles GauthierAbstract:Individual variation in timing of migration: causes and reproductive consequences in greater snow geese (Anser caerulescens atlanticus
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77 © WILDLIFE BIOLOGY · 9:3 (2003) Effects of collar-attached transmitters on behaviour, pair bond and breeding success of snow geese Anser caerulescens atlanticus
2016Co-Authors: Frederic Demers, Jeanfrancois Giroux, Gilles Gauthier, Joel BetyAbstract:transmitters on behaviour, pair bond and breeding success of snow geese Anser caerulescens atlanticus.- Wildl. Biol. 9: 77-86. There is growing evidence that harnesses may not be an effective technique to attach radio-transmitters on geese. The use of neck collars is an alternative, but studies on the effect of collars with or without radios on geese have reached divergent conclusions. As our objective was to determine if radio neck collars affect behaviour, pair bonds and breeding success of greater snow geese Anser caerulescens atlanticus, we fitted 230 females with radio neck collars during the 1995-1998 moulting periods on Bylot Island, Nunavut. Data were subse-quently obtained for 159 birds on the staging and breeding grounds. Radios rep-resented 2.5 ± 0.1 % ( ± SE) of the birds’body mass. Unmarked geese and those fitted with conventional plastic collars served as controls. The behaviour of radio-collared geese was affected during the first fall after marking, but negative effects disappeared thereafter. Geese with conventional collars had similar behaviour as unmarked birds. Divorce rates were low for birds with conventional collars (0-4%), but were as great as 30 % for radio-collared geese. We suggest that the modified behaviour of the radio-collared females promoted separation from the male. Apparent breeding propensity, nest initiation date, clutch size and nest-ing success of radio-marked birds were also negatively affected. Until better alternatives are developed, we recommend minimizing the mass of radio col-lars to < 2.5 % of the birds ’ body mass and reducing the antenna length. This implies a trade-off between effects on birds and performance of the transmit-ters in terms of battery mass (longevity) and antenna length (range)
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benefiting from a migratory prey spatio temporal patterns in allochthonous subsidization of an arctic predator
Journal of Animal Ecology, 2012Co-Authors: Gilles Gauthier, Dominique Berteaux, Marieandree Giroux, Nicolas Lecomte, Guillaume Szor, Joel BetyAbstract:Summary 1. Flows of nutrients and energy across ecosystem boundaries have the potential to subsidize consumer populations and modify the dynamics of food webs, but how spatio-temporal variations in autochthonous and allochthonous resources affect consumers’ subsidization remains largely unexplored. 2. We studied spatio-temporal patterns in the allochthonous subsidization of a predator living in a relatively simple ecosystem. We worked on Bylot Island (Nunavut, Canada), where arctic foxes (Vulpes lagopus L.) feed preferentially on lemmings (Lemmus trimucronatus and Dicrostonyx groenlandicus Traill), and alternatively on colonial greater snow geese (Anser caerulescens atlanticus L.). Geese migrate annually from their wintering grounds (where they feed on farmlands and marshes) to the Canadian Arctic, thus generating a strong flow of nutrients and energy across ecosystem boundaries. 3. We examined the influence of spatial variations in availability of geese on the diet of fox cubs (2003–2005) and on fox reproductive output (1996–2005) during different phases of the lemming cycle. 4. Using stable isotope analysis and a simple statistical routine developed to analyse the outputs of a multisource mixing model (SIAR), we showed that the contribution of geese to the diet of arctic fox cubs decreased with distance from the goose colony. 5. The probability that a den was used for reproduction by foxes decreased with distance from the subsidized goose colony and increased with lemming abundance. When lemmings were highly abundant, the effect of distance from the colony disappeared. The goose colony thus generated a spatial patterning of reproduction probability of foxes, while the lemming cycle generated a strong temporal variation of reproduction probability of foxes. 6. This study shows how the input of energy owing to the large-scale migration of prey affects the functional and reproductive responses of an opportunistic consumer, and how this input is spatially and temporally modulated through the foraging behaviour of the consumer. Thus, perspectives of both landscape and foraging ecology are needed to fully resolve the effects of subsidies on animal demographic processes and population dynamics.
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climate trophic interactions density dependence and carry over effects on the population productivity of a migratory arctic herbivorous bird
Oikos, 2010Co-Authors: Manon Morrissette, Gilles Gauthier, Joel Bety, Austin Reed, Josee LefebvreAbstract:Several driving forces can aff ect recruitment rates in bird populations. However, our understanding of climate-induced eff ects or bottom–up vs top–down biological processes on breeding productivity typically comes from small-scale studies, and their relative importance is rarely investigated at the population level. Using a 31-year time series, we examined the eff ects of selected environmental parameters on the annual productivity of a key Arctic herbivore, the greater snow goose Anser caerulescens atlanticus. We determined the extent to which breeding productivity, defi ned as the percentage of juveniles in the fall population, was aff ected by 1) climatic conditions, 2) fl uctuations in predation pressure caused by small rodent oscillations, and 3) population size. Moreover, we took advantage of an unplanned large-scale manipulation (i.e. management action) to examine the potential non-lethal carry-over eff ects caused by disturbance on spring staging sites. Th e most parsimonious model explained 66% of the annual variation in goose productivity. Th e spring North Atlantic Oscillation and Arctic snow depth were the primary climatic parameters inversely aff ecting the production of juveniles, likely through bottom–up processes. Indirect trophic interactions generated by fl uctuations in lemming abundance explained 18% of the variation in goose productivity (positive relationship). Mean temperature during brood-rearing and disturbance on staging sites (carry-over eff ects) were the other important factors aff ecting population recruitment. We observed a strong population increase, and found no evidence of density-dependent eff ects. Spatially restricted studies can identify factors linking environmental parameters to local bird reproduction but if these factors do not act synchronously over the species range, they may fail to identify the relative importance of mechanisms driving large-scale population dynamics.
Jeanfrancois Giroux - One of the best experts on this subject based on the ideXlab platform.
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the greater snow goose Anser caerulescens atlanticus managing an overabundant population
AMBIO: A Journal of the Human Environment, 2017Co-Authors: Josee Lefebvre, Jeanfrancois Giroux, Gilles Gauthier, Austin Reed, Eric T Reed, Luc BelangerAbstract:Between the early 1900s and the 1990s, the greater snow goose Anser caerulescens atlanticus population grew from 3000 individuals to more than 700 000. Because of concerns about Arctic degradation of natural habitats through overgrazing, a working group recommended the stabilization of the population. Declared overabundant in 1998, special management actions were then implemented in Canada and the United States. Meanwhile, a cost–benefit socioeconomic analysis was performed to set a target population size. Discussions aiming towards attaining a common vision were undertaken with stakeholders at multiple levels. The implemented measures have had varying success; but population size has been generally stable since 1999. To be effective and meet social acceptance, management actions must have a scientific basis, result from a consensus among stakeholders, and include an efficient monitoring programme. In this paper, historical changes in population size and management decisions along with past and current challenges encountered are discussed.
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77 © WILDLIFE BIOLOGY · 9:3 (2003) Effects of collar-attached transmitters on behaviour, pair bond and breeding success of snow geese Anser caerulescens atlanticus
2016Co-Authors: Frederic Demers, Jeanfrancois Giroux, Gilles Gauthier, Joel BetyAbstract:transmitters on behaviour, pair bond and breeding success of snow geese Anser caerulescens atlanticus.- Wildl. Biol. 9: 77-86. There is growing evidence that harnesses may not be an effective technique to attach radio-transmitters on geese. The use of neck collars is an alternative, but studies on the effect of collars with or without radios on geese have reached divergent conclusions. As our objective was to determine if radio neck collars affect behaviour, pair bonds and breeding success of greater snow geese Anser caerulescens atlanticus, we fitted 230 females with radio neck collars during the 1995-1998 moulting periods on Bylot Island, Nunavut. Data were subse-quently obtained for 159 birds on the staging and breeding grounds. Radios rep-resented 2.5 ± 0.1 % ( ± SE) of the birds’body mass. Unmarked geese and those fitted with conventional plastic collars served as controls. The behaviour of radio-collared geese was affected during the first fall after marking, but negative effects disappeared thereafter. Geese with conventional collars had similar behaviour as unmarked birds. Divorce rates were low for birds with conventional collars (0-4%), but were as great as 30 % for radio-collared geese. We suggest that the modified behaviour of the radio-collared females promoted separation from the male. Apparent breeding propensity, nest initiation date, clutch size and nest-ing success of radio-marked birds were also negatively affected. Until better alternatives are developed, we recommend minimizing the mass of radio col-lars to < 2.5 % of the birds ’ body mass and reducing the antenna length. This implies a trade-off between effects on birds and performance of the transmit-ters in terms of battery mass (longevity) and antenna length (range)
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ARCTIC Habitat Use by Greater Snow Geese During the Brood-Rearing Period
2015Co-Authors: Jeanfrancois GirouxAbstract:ABSTRACT. Observations of habitat use by the Greater Snow Goose (Anser caerulescens atlanricus) were conducted at Jungersen Bay, northern Baffin Island, from 27 July- 17 August 1981. Density of geese using the study area was estimated at 425 birds.km-2. The average of 2.8 young per family did not change during our study. Non-breeding geese were first observed in flight on I August and were seen regularly until 13 August. Three types of habitat used by geese during the brood-rearing period were distinguished: tidal marshes dominated by Carex subsparhacea and Puccinellia phryganodes; wet moss-covered meadows with up to 5 cm of standing water, dominated by Carex srans, Duponriafisheri, Calamagrosris neglecra, and Arctagrosris latifolia; and, around ponds, bands of vegetation 1-2 m wide dominated by Carex srans. The three most important species of monocots grazed by geese were Puccinelliaphrygwwdes, Carex subspathacea, and C. srans. It is unlikely that habitat and food resources are limiting factors for Greater Snow Geese in the High Arctic during the brood-rearing period. We suggest that potential breeding areas for this species be iden-tified and given special protection
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ORIGINAL PAPER Cache and carry: hoarding behavior of arctic fox
2014Co-Authors: Jeanfrancois Giroux, Vincent Careau, Dominique Berteaux, -f. J. GirouxAbstract:Abstract Food-hoarding animals are expected to preferentially cache items with lower perishability and/or higher consumption time. We observed arctic foxes (Alopex lagopus) foraging in a greater snow goose (Anser caerulescens atlanticus) colony where the main prey of foxes consisted of goose eggs, goslings, and lemmings (Lemmus and Dicrostonyx spp.). We recorded the number of prey consumed and cached and the time that foxes invested in these activities. Foxes took more time to consume a goose egg than a lemming or gosling but cached a greater proportion of eggs than the other prey type. This may be caused by the eggshell, which presumably decreases the perishability and/or pilfering risk of cached eggs, but also increases egg consumption time. Arctic foxes usually Communicated by E. Korpimäk
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cache and carry hoarding behavior of arctic fox
Behavioral Ecology and Sociobiology, 2007Co-Authors: Jeanfrancois Giroux, Vincent Careau, Dominique BerteauxAbstract:Food-hoarding animals are expected to preferentially cache items with lower perishability and/or higher consumption time. We observed arctic foxes (Alopex lagopus) foraging in a greater snow goose (Anser caerulescens atlanticus) colony where the main prey of foxes consisted of goose eggs, goslings, and lemmings (Lemmus and Dicrostonyx spp.). We recorded the number of prey consumed and cached and the time that foxes invested in these activities. Foxes took more time to consume a goose egg than a lemming or gosling but cached a greater proportion of eggs than the other prey type. This may be caused by the eggshell, which presumably decreases the perishability and/or pilfering risk of cached eggs, but also increases egg consumption time. Arctic foxes usually recached goose eggs but rarely recached goslings or lemmings. We tested whether the rapid-sequestering hypothesis could explain this recaching behavior. According to this hypothesis, arctic foxes may adopt a two-stage strategy allowing both to maximize egg acquisition rate in an undefended nest and subsequently secure eggs in potentially safer sites. Foxes spent more time carrying an egg and traveled greater distances when establishing a secondary than a primary cache. To gain further information on the location and subsequent fate of cached eggs, we used dummy eggs containing radio transmitters. Lifespan of primary caches increased with distance from the goose nest. Secondary caches were generally located farther from the nest and had a longer lifespan than primary caches. Behavioral observations and the radio-tagged egg technique both gave results supporting the rapid-sequestering hypothesis.
Fred Cooke - One of the best experts on this subject based on the ideXlab platform.
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© 2004 British Ornithologists ’ Union Blackwell Publishing, Ltd. First pairing in Snow Geese Anser caerulescens: at what age and at what time of year does it occur?
2015Co-Authors: Barbara Ganter, Sean W. Boyd, Vasily V. Baranyuk, Fred CookeAbstract:In migratory birds, the place and time of pair formation are important parameters for population structure and dynamics. Geese are not only migratory but also exhibit long-term monogamy, and therefore the first pairing event in a bird’s lifetime is of particular import-ance. Through behavioural observations of young, known-age, marked birds conducted on the wintering grounds during three winter seasons we investigated two aspects of the timing of first pair formation in the Wrangel Island population of Snow Geese Anser caerulescens: (1) the age at which birds first form pair bonds, and (2) the seasonal pattern of first pair formation. Wrangel Island Snow Geese paired considerably later in life than Snow Geese from a low-Arctic population: almost none of the birds formed pairs in their second winter, and many were still in sibling groups for at least part of that season. The proportion of birds in pairs continued to increase until at least 5 years of age. Most pairing took place during the observation periods, and in general the proportion of birds in pair bonds increased gradually throughout the winter season. The amount of pairing during spring migration or summer varied annually and among cohorts, indicating that even very young birds may be able to form pair bonds quickly if conditions on the breeding grounds are unusually favourable. Pairin
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intraseasonal variation in the development of sexual size dimorphism in a precocial bird evidence from the lesser snow goose
Journal of Animal Ecology, 1996Co-Authors: Evan G Cooch, David B. Lank, Fred CookeAbstract:Among species which feed their young, particularly those with large size dimorphism, parental investment trade-offs between growth and survival of male and female offspring, and parental fitness, may be significant (sensu Trivers & Willard 1973). In contrast, little is known about the effects of variation in food supply on sex-differential growth and survival in species with precocial young. In such cases, where parental investment is generally smaller, the trade-off is more proximate ; how should individual offspring allocate resources to maximize their fitness. We examined this question by assessing the effects of seasonal variation in feeding conditions on growth and survival of male and female offspring of an obligate avian herbivore with precocial young, the lesser snow goose (Anser caerulescens caerulescens L.), using long-term observational data from 1969 to present. Snow geese show limited sexual size dimorphism, with males being 2-6% larger at all ages post-hatching. Growth of snow goose goslings has been previously shown to be extremely sensitive to variation in food supply, and previous analysis of this species indicated even small differences in growth rates may significantly affect the probability of survival. We found a highly significant difference in the relative body mass, but not structural size, of male and female goslings at fledging in response to seasonal declines in food supply, with males showing a greater proportional fledging mass decrease than females. Despite growth differences there was no detectable seasonal variation in gosling survival between the sexes, and no difference between male and female goslings in survival to fledging overall. Since the analysis involved only goslings which had survived to fledging, it can be difficult to determine if the seasonal decrease in dimorphism reflects either (i) seasonal differences in relative growth of male and female goslings, or (ii) increasing mortality of larger male goslings later in the season. However, the failure to find any sex-specific differences in mortality generally favours the hypothesis of proportionately slower growth of males hatched later in the season. The lack of sexual differences in survival despite measurable differences in sex-specific growth may reflect some level of adaptation to maximize the probability of survival of each sex. However, the possibility that the proportionately greater seasonal declines exhibited by males may reflect a simple constraint, rather than an adaptation, cannot presently be ruled out.
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dominance brood size and foraging behavior during brood rearing in the lesser snow goose an experimental study
The Condor, 1995Co-Authors: R S Mulder, T D Williams, Fred CookeAbstract:We investigated the relationship between brood size and social dominance during the brood-rearing period in Lesser Snow Geese (Anser caerulescens caerulescens) by experimentally manipulating food availability to create high-biomass food patches. A total of 128 social interactions were subsequently observed in experimental areas; the rate of interactions was significantly higher in experimental high-biomass plots (9.6 hr −1 ) than in control, low-biomass, areas (0.4 hr −1 ). During social interactions families (pairs with one or more goslings) were always dominant over pairs without goslings. However, there was no clear dominance hierarchy among families in relation to brood size. Neither aggressiveness (the number of interactions initiated) nor the proportion of successful interactions varied consistently with brood size. We conclude that, during brood rearing, dominance ranking is determined more by individual variation in aggressiveness of adult (parent) birds, rather than by any «motivational» effect of offspring or by brood size per se. Geese fed longer in the high biomass plots (mean 19.2 min per visit) than in control plots (2.9 min), and birds «defended» high biomass areas: 32% of all interactions involved a social unit inside the experimental plot driving off a social unit which was trying to enter the plot from outside. This suggests that geese derived benefits from monopolization of good quality food patches. The behavior of foraging geese varied in relation to food availability: birds took fewer steps per minute during both feeding and non-feeding bouts in the experimental plots and females, but not males, had shorter feeding bouts in experimental plots, i.e., they adopted the vigilant head-up posture more frequently. We suggest that the benefits of utilizing high biomass food patches during brood-rearing include higher intake rates, decreased energetic costs of foraging and reduced predation risk through increased vigilance behavior by parents and greater cohesion of the family unit
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environmental degradation food limitation and reproductive output juvenile survival in lesser snow geese
Journal of Animal Ecology, 1993Co-Authors: Tony D Williams, Evan G Cooch, R L Jefferies, Fred CookeAbstract:Long-term changes in pre-fledging gosling survival, in relation to food availability, were investigated in a population of lesser snow geese (Anser caerulescens caerulescens) at La Perouse Bay, Manitoba. Both colony size and the density of birds using brood-rearing areas increased over the duration of the study (the former from 2000 to 8-9000 pairs). Annual mean size of broods using traditional brood-rearing areas (as a proportion of initial brood size) declined significantly between 1979 and 1991, from 0.9-1.0 to 0.6-0.8. Mean proportion of marked goslings in a brood that survived from hatch to ringing (5-6 weeks of age) declined from approximately 65% prior to 1980 to 35-40% in recent years
Vincent Careau - One of the best experts on this subject based on the ideXlab platform.
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ORIGINAL PAPER Cache and carry: hoarding behavior of arctic fox
2014Co-Authors: Jeanfrancois Giroux, Vincent Careau, Dominique Berteaux, -f. J. GirouxAbstract:Abstract Food-hoarding animals are expected to preferentially cache items with lower perishability and/or higher consumption time. We observed arctic foxes (Alopex lagopus) foraging in a greater snow goose (Anser caerulescens atlanticus) colony where the main prey of foxes consisted of goose eggs, goslings, and lemmings (Lemmus and Dicrostonyx spp.). We recorded the number of prey consumed and cached and the time that foxes invested in these activities. Foxes took more time to consume a goose egg than a lemming or gosling but cached a greater proportion of eggs than the other prey type. This may be caused by the eggshell, which presumably decreases the perishability and/or pilfering risk of cached eggs, but also increases egg consumption time. Arctic foxes usually Communicated by E. Korpimäk
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cache and carry hoarding behavior of arctic fox
Behavioral Ecology and Sociobiology, 2007Co-Authors: Jeanfrancois Giroux, Vincent Careau, Dominique BerteauxAbstract:Food-hoarding animals are expected to preferentially cache items with lower perishability and/or higher consumption time. We observed arctic foxes (Alopex lagopus) foraging in a greater snow goose (Anser caerulescens atlanticus) colony where the main prey of foxes consisted of goose eggs, goslings, and lemmings (Lemmus and Dicrostonyx spp.). We recorded the number of prey consumed and cached and the time that foxes invested in these activities. Foxes took more time to consume a goose egg than a lemming or gosling but cached a greater proportion of eggs than the other prey type. This may be caused by the eggshell, which presumably decreases the perishability and/or pilfering risk of cached eggs, but also increases egg consumption time. Arctic foxes usually recached goose eggs but rarely recached goslings or lemmings. We tested whether the rapid-sequestering hypothesis could explain this recaching behavior. According to this hypothesis, arctic foxes may adopt a two-stage strategy allowing both to maximize egg acquisition rate in an undefended nest and subsequently secure eggs in potentially safer sites. Foxes spent more time carrying an egg and traveled greater distances when establishing a secondary than a primary cache. To gain further information on the location and subsequent fate of cached eggs, we used dummy eggs containing radio transmitters. Lifespan of primary caches increased with distance from the goose nest. Secondary caches were generally located farther from the nest and had a longer lifespan than primary caches. Behavioral observations and the radio-tagged egg technique both gave results supporting the rapid-sequestering hypothesis.