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Martin U. Grüebler - One of the best experts on this subject based on the ideXlab platform.
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Post-Fledging survival of altricial birds: ecological determinants and adaptation
Journal of Field Ornithology, 2016Co-Authors: Beat Naef-daenzer, Martin U. GrüeblerAbstract:For altricial young, Fledging is an abrupt step into an unknown environment. Despite increasing numbers of studies addressing the post-Fledging period, our current knowledge of the causes and consequences of post-Fledging survival remains fragmentary. Here, we review the literature on post-Fledging survival of juvenile altricial birds, addressing the following main questions: Is low post-Fledging survival a bottleneck in the altricial reproductive cycle? What is known of proximate and ultimate causal factors such as trophic relations (food and predation), habitat conditions, or abiotic factors acting in the post-Fledging period? We analyzed weekly survival estimates from 123 data series based on studies of 65 species, covering weeks 1–13 post-Fledging. As a general pattern, survival of fledglings was low during the first week post-Fledging (median rate = 0.83), and improved rapidly with time post-Fledging (week 4 median rate = 0.96). For ground-nesting species, survival immediately after leaving nests was similar to egg-to-Fledging survival. For species breeding above-ground, survival during the first week post-Fledging was substantially lower than during both the nestling period and later post-Fledging stages. Thus, the early post-Fledging period is a bottleneck of markedly elevated mortality for most altricial species. Predation was the main proximate cause of mortality. Various factors such as habitat, annual and seasonal variation in the environment, and the physical condition of fledglings have been found to affect post-Fledging survival. Individual survival depended strongly on physical traits such as mass and wing length, which likely influence the ability of fledglings to escape predation. Trophic relationships at various levels are the main ultimate driver of adaptation of traits relevant to survival during the pre- and post-Fledging periods. Spatiotemporal dynamics of food resources determine the physical development of juveniles and, in turn, their performance after Fledging. However, predators can cause quick and efficient selection for fledgling traits and adult breeding decisions. Parental strategies related to clutch size and timing of breeding, and the age and developmental stage at which young fledge have substantial effects on post-Fledging survival. The intensity and duration of post-Fledging parental investment also influences fledgling survival. Post-Fledging mortality is therefore not a random and inevitable loss. Traits and strategies related to Fledging and the post-Fledging stage create large fitness differentials and, therefore, are integral, yet poorly understood, parts of the altricial reproductive strategy.
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survival benefits of post Fledging care experimental approach to a critical part of avian reproductive strategies
Journal of Animal Ecology, 2010Co-Authors: Martin U. Grüebler, Beat NaefdaenzerAbstract:Summary 1. Caring for offspring beyond leaving the nest is an important but under-studied part of avian life histories. Theory predicts that prolonged post-Fledging parental care should yield fitness benefits such as increased fledgling survival. Post-Fledging care is also costly in terms of time and energy available for subsequent reproduction, moult or migration. So far, direct measurements of the fitness effects of the duration of post-Fledging parental care are lacking. 2. In a partial cross-fostering experiment, barn swallow (Hirundo rustica) chicks were exchanged among broods close to Fledging. Thereby, we separated the effects of post-Fledging care from those of pre-Fledging origin on juvenile survival. 3. Prolonging post-Fledging care substantially increased juvenile survival up to 3 weeks post-Fledging. Juvenile mortality was maximal in the days following the termination of parental care, and prolonging care delayed and reduced this peak mortality. Survival of fledglings experiencing 6 days of care was Φ = 0·227, whereas fledglings experiencing 14 days of care showed a survival of Φ = 0·571. 4. Offspring from pairs providing short care showed lower post-Fledging survival than did offspring from pairs providing long care, irrespective of the actual duration of care experienced. This gives evidence for an additional survival effect of pre-Fledging factors associated with the parental duration of care. 5. The results suggest that differential survival in relation to post-Fledging parental care is a major fitness component. This relationship has profound effects on the reproductive trade-offs underlying the evolution of avian life histories.
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Survival benefits of post‐Fledging care: experimental approach to a critical part of avian reproductive strategies
The Journal of animal ecology, 2010Co-Authors: Martin U. Grüebler, Beat Naef-daenzerAbstract:Summary 1. Caring for offspring beyond leaving the nest is an important but under-studied part of avian life histories. Theory predicts that prolonged post-Fledging parental care should yield fitness benefits such as increased fledgling survival. Post-Fledging care is also costly in terms of time and energy available for subsequent reproduction, moult or migration. So far, direct measurements of the fitness effects of the duration of post-Fledging parental care are lacking. 2. In a partial cross-fostering experiment, barn swallow (Hirundo rustica) chicks were exchanged among broods close to Fledging. Thereby, we separated the effects of post-Fledging care from those of pre-Fledging origin on juvenile survival. 3. Prolonging post-Fledging care substantially increased juvenile survival up to 3 weeks post-Fledging. Juvenile mortality was maximal in the days following the termination of parental care, and prolonging care delayed and reduced this peak mortality. Survival of fledglings experiencing 6 days of care was Φ = 0·227, whereas fledglings experiencing 14 days of care showed a survival of Φ = 0·571. 4. Offspring from pairs providing short care showed lower post-Fledging survival than did offspring from pairs providing long care, irrespective of the actual duration of care experienced. This gives evidence for an additional survival effect of pre-Fledging factors associated with the parental duration of care. 5. The results suggest that differential survival in relation to post-Fledging parental care is a major fitness component. This relationship has profound effects on the reproductive trade-offs underlying the evolution of avian life histories.
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Post-Fledging Range use of Great Tit Parus major Families in Relation to Chick Body Condition
Ardea, 2008Co-Authors: Beat Naef-daenzer, Martin U. GrüeblerAbstract:The timing of breeding and the chicks' Fledging condition are major fitness-relevant traits in the Great Tit Parus major. Yet, the proximate mechanisms relating these traits to differential survival and recruitment are largely unknown. We analysed the range use of Great Tit family groups during the first 20 days after Fledging, i.e. the period of post-Fledging dependence, in relation to the juveniles' body condition. Radio-telemetry and colour marks were used to track 25 families with 107 chicks. The post-Fledging home-ranges of families with fledglings of good condition (average body mass 19 g) were c. 3 times larger than of those with poorly nourished (average 15 g) young. The rate of movements exceeding 50 m per hour was also positively correlated to the chicks' mean Fledging mass. We hypothesise that the fledglings' body condition resulted in large differences in flight performance, and consequently, spatial behaviour of the family groups. The slow movements and the close grouping of chicks of poor bo...
Tony D. Williams - One of the best experts on this subject based on the ideXlab platform.
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physiological maturity at a critical life history transition and flight ability at Fledging
Functional Ecology, 2017Co-Authors: Allison Cornell, Kate F. Gibson, Tony D. WilliamsAbstract:Summary 1.Developmental maturity (e.g. body condition, body mass) at major life history transitions is known to affect fitness across a wide range of taxa. 2.Fledging (leaving the nest), a major life-history transition in birds, is associated with high post-Fledging mortality and is widely assumed to be related to poor initial flight ability of fledglings which, in turn, might be related to developmental maturity at Fledging. 3.We investigated individual variation in developmental maturity of both somatic and physiological traits at this critical life history transition in different ecological contexts (year, 1st or 2nd broods) to determine the importance of physiological traits related to oxygen-carrying capacity (hematocrit, hemoglobin) for individual variation in initial flight ability at Fledging. 4.Hemoglobin concentration and hematocrit at Fledging had much higher variance than somatic traits and were more variable across ecological contexts. Furthermore, fledgling hemoglobin concentration was the least developmentally mature of all traits (on average only 78% of adult concentration). 5.Fledglings from 2nd broods, which are known to have lower post-Fledging survival, were less developmentally mature than fledglings from 1st broods for all traits (except tarsus), with hematocrit and hemoglobin concentration being the most developmentally immature traits (in 1st vs. 2nd broods, hematocrit: 47.1% vs. 40.9%; hemoglobin: 13.3 g/dL vs. 11.6 g/dL). 6.Models predicting individual variation in two aspects of initial flight ability (total energy gain, take-off angle) were significantly improved when physiological traits (in particular hemoglobin) were incorporated into models based on somatic traits. This article is protected by copyright. All rights reserved.
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Physiological maturity at a critical life‐history transition and flight ability at Fledging
Functional Ecology, 2016Co-Authors: Allison Cornell, Kate F. Gibson, Tony D. WilliamsAbstract:Summary 1.Developmental maturity (e.g. body condition, body mass) at major life history transitions is known to affect fitness across a wide range of taxa. 2.Fledging (leaving the nest), a major life-history transition in birds, is associated with high post-Fledging mortality and is widely assumed to be related to poor initial flight ability of fledglings which, in turn, might be related to developmental maturity at Fledging. 3.We investigated individual variation in developmental maturity of both somatic and physiological traits at this critical life history transition in different ecological contexts (year, 1st or 2nd broods) to determine the importance of physiological traits related to oxygen-carrying capacity (hematocrit, hemoglobin) for individual variation in initial flight ability at Fledging. 4.Hemoglobin concentration and hematocrit at Fledging had much higher variance than somatic traits and were more variable across ecological contexts. Furthermore, fledgling hemoglobin concentration was the least developmentally mature of all traits (on average only 78% of adult concentration). 5.Fledglings from 2nd broods, which are known to have lower post-Fledging survival, were less developmentally mature than fledglings from 1st broods for all traits (except tarsus), with hematocrit and hemoglobin concentration being the most developmentally immature traits (in 1st vs. 2nd broods, hematocrit: 47.1% vs. 40.9%; hemoglobin: 13.3 g/dL vs. 11.6 g/dL). 6.Models predicting individual variation in two aspects of initial flight ability (total energy gain, take-off angle) were significantly improved when physiological traits (in particular hemoglobin) were incorporated into models based on somatic traits. This article is protected by copyright. All rights reserved.
Beat Naef-daenzer - One of the best experts on this subject based on the ideXlab platform.
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Post-Fledging survival of altricial birds: ecological determinants and adaptation
Journal of Field Ornithology, 2016Co-Authors: Beat Naef-daenzer, Martin U. GrüeblerAbstract:For altricial young, Fledging is an abrupt step into an unknown environment. Despite increasing numbers of studies addressing the post-Fledging period, our current knowledge of the causes and consequences of post-Fledging survival remains fragmentary. Here, we review the literature on post-Fledging survival of juvenile altricial birds, addressing the following main questions: Is low post-Fledging survival a bottleneck in the altricial reproductive cycle? What is known of proximate and ultimate causal factors such as trophic relations (food and predation), habitat conditions, or abiotic factors acting in the post-Fledging period? We analyzed weekly survival estimates from 123 data series based on studies of 65 species, covering weeks 1–13 post-Fledging. As a general pattern, survival of fledglings was low during the first week post-Fledging (median rate = 0.83), and improved rapidly with time post-Fledging (week 4 median rate = 0.96). For ground-nesting species, survival immediately after leaving nests was similar to egg-to-Fledging survival. For species breeding above-ground, survival during the first week post-Fledging was substantially lower than during both the nestling period and later post-Fledging stages. Thus, the early post-Fledging period is a bottleneck of markedly elevated mortality for most altricial species. Predation was the main proximate cause of mortality. Various factors such as habitat, annual and seasonal variation in the environment, and the physical condition of fledglings have been found to affect post-Fledging survival. Individual survival depended strongly on physical traits such as mass and wing length, which likely influence the ability of fledglings to escape predation. Trophic relationships at various levels are the main ultimate driver of adaptation of traits relevant to survival during the pre- and post-Fledging periods. Spatiotemporal dynamics of food resources determine the physical development of juveniles and, in turn, their performance after Fledging. However, predators can cause quick and efficient selection for fledgling traits and adult breeding decisions. Parental strategies related to clutch size and timing of breeding, and the age and developmental stage at which young fledge have substantial effects on post-Fledging survival. The intensity and duration of post-Fledging parental investment also influences fledgling survival. Post-Fledging mortality is therefore not a random and inevitable loss. Traits and strategies related to Fledging and the post-Fledging stage create large fitness differentials and, therefore, are integral, yet poorly understood, parts of the altricial reproductive strategy.
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Survival benefits of post‐Fledging care: experimental approach to a critical part of avian reproductive strategies
The Journal of animal ecology, 2010Co-Authors: Martin U. Grüebler, Beat Naef-daenzerAbstract:Summary 1. Caring for offspring beyond leaving the nest is an important but under-studied part of avian life histories. Theory predicts that prolonged post-Fledging parental care should yield fitness benefits such as increased fledgling survival. Post-Fledging care is also costly in terms of time and energy available for subsequent reproduction, moult or migration. So far, direct measurements of the fitness effects of the duration of post-Fledging parental care are lacking. 2. In a partial cross-fostering experiment, barn swallow (Hirundo rustica) chicks were exchanged among broods close to Fledging. Thereby, we separated the effects of post-Fledging care from those of pre-Fledging origin on juvenile survival. 3. Prolonging post-Fledging care substantially increased juvenile survival up to 3 weeks post-Fledging. Juvenile mortality was maximal in the days following the termination of parental care, and prolonging care delayed and reduced this peak mortality. Survival of fledglings experiencing 6 days of care was Φ = 0·227, whereas fledglings experiencing 14 days of care showed a survival of Φ = 0·571. 4. Offspring from pairs providing short care showed lower post-Fledging survival than did offspring from pairs providing long care, irrespective of the actual duration of care experienced. This gives evidence for an additional survival effect of pre-Fledging factors associated with the parental duration of care. 5. The results suggest that differential survival in relation to post-Fledging parental care is a major fitness component. This relationship has profound effects on the reproductive trade-offs underlying the evolution of avian life histories.
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Post-Fledging Range use of Great Tit Parus major Families in Relation to Chick Body Condition
Ardea, 2008Co-Authors: Beat Naef-daenzer, Martin U. GrüeblerAbstract:The timing of breeding and the chicks' Fledging condition are major fitness-relevant traits in the Great Tit Parus major. Yet, the proximate mechanisms relating these traits to differential survival and recruitment are largely unknown. We analysed the range use of Great Tit family groups during the first 20 days after Fledging, i.e. the period of post-Fledging dependence, in relation to the juveniles' body condition. Radio-telemetry and colour marks were used to track 25 families with 107 chicks. The post-Fledging home-ranges of families with fledglings of good condition (average body mass 19 g) were c. 3 times larger than of those with poorly nourished (average 15 g) young. The rate of movements exceeding 50 m per hour was also positively correlated to the chicks' mean Fledging mass. We hypothesise that the fledglings' body condition resulted in large differences in flight performance, and consequently, spatial behaviour of the family groups. The slow movements and the close grouping of chicks of poor bo...
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Differential post-Fledging survival of great and coal tits in relation to their condition and Fledging date
Journal of Animal Ecology, 2001Co-Authors: Beat Naef-daenzer, Fritz Widmer, Maria NuberAbstract:Summary 1 We present a multivariate model of the post-Fledging survival of juvenile great and coal tits (Parus major L., P. ater L.) in relation to chick body condition and timing of breeding. Radio-telemetry and colour marks were used to track tit families during 20 days from Fledging, that is, the period of post-Fledging dependence. Data on 342 chicks of 68 broods were obtained. 2 Forty-seven per cent of juveniles died during the observation period, predation being the main cause of mortality. In the first 4 days after Fledging the mortality rate was 5–10% per day. 3 Survival of juveniles was positively correlated with Fledging mass. Furthermore, survival strongly decreased during the season. In the second half of June, mortality was five times the rate of mid-May. The differential survival resulted in selection for both early Fledging and high Fledging mass. Juvenile condition was less important for survival in birds that had fledged early in the season. Their survival rates exceeded 70% in all weight classes, whereas in late broods only the heaviest individuals survived equally well. The survival of birds Fledging both late and in poor condition was below 20%. Thus, selection for high Fledging mass was much stronger in the late season than in early broods. 4 We conclude that the impact of predation after leaving the nest results in selection for early breeding and, particularly in the late season, for high Fledging mass. This may explain why the earliest broods have been found to produce most recruits into the breeding population even if they did not profit from maximum food availability during the nestling period. On the other hand, energetic limitations may constrain the begin of egg laying in adult birds. Thus, counteracting evolutionary responses to the seasonal development of food availability (the caterpillar peak) and to the risk of post-Fledging mortality (the peak in post-Fledging mortality) may have focused the period of optimal reproduction to a narrow time-window.
Erich Kaiser - One of the best experts on this subject based on the ideXlab platform.
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do fledgling and pre breeding common swifts apus apus take part in aerial roosting an answer from a radiotracking experiment
Ibis, 2008Co-Authors: Michael K Tarburton, Erich KaiserAbstract:This study has shown that fledgling Common Swifts Apus apus spend the first post-Fledging night of their life on the wing and that pre-breeders also spend the full night on the wing. Even though this work was conducted during an unusually cold, wet period, the results show that fledglings do not return to their natal colony in the week after Fledging. It also demonstrates that yearlings are only slightly more likely than fledglings to spend any time at a particular colony, but are more likely to move from colony to colony. Older pre-breeders are more likely to spend more time at and revisit a particular colony more often than yearlings. It is our observation that only right at the end of the breeding duties will the parents participate in an evening ascent, and even then many of them return to their nest for the evening. Breeding adults displayed the greatest devotion to a particular colony. But even among such adults we detected some that ceased caring for their young a few days prior to their Fledging. Adults roost in their nestbox if they meet with bad weather.
Allison Cornell - One of the best experts on this subject based on the ideXlab platform.
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physiological maturity at a critical life history transition and flight ability at Fledging
Functional Ecology, 2017Co-Authors: Allison Cornell, Kate F. Gibson, Tony D. WilliamsAbstract:Summary 1.Developmental maturity (e.g. body condition, body mass) at major life history transitions is known to affect fitness across a wide range of taxa. 2.Fledging (leaving the nest), a major life-history transition in birds, is associated with high post-Fledging mortality and is widely assumed to be related to poor initial flight ability of fledglings which, in turn, might be related to developmental maturity at Fledging. 3.We investigated individual variation in developmental maturity of both somatic and physiological traits at this critical life history transition in different ecological contexts (year, 1st or 2nd broods) to determine the importance of physiological traits related to oxygen-carrying capacity (hematocrit, hemoglobin) for individual variation in initial flight ability at Fledging. 4.Hemoglobin concentration and hematocrit at Fledging had much higher variance than somatic traits and were more variable across ecological contexts. Furthermore, fledgling hemoglobin concentration was the least developmentally mature of all traits (on average only 78% of adult concentration). 5.Fledglings from 2nd broods, which are known to have lower post-Fledging survival, were less developmentally mature than fledglings from 1st broods for all traits (except tarsus), with hematocrit and hemoglobin concentration being the most developmentally immature traits (in 1st vs. 2nd broods, hematocrit: 47.1% vs. 40.9%; hemoglobin: 13.3 g/dL vs. 11.6 g/dL). 6.Models predicting individual variation in two aspects of initial flight ability (total energy gain, take-off angle) were significantly improved when physiological traits (in particular hemoglobin) were incorporated into models based on somatic traits. This article is protected by copyright. All rights reserved.
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Physiological maturity at a critical life‐history transition and flight ability at Fledging
Functional Ecology, 2016Co-Authors: Allison Cornell, Kate F. Gibson, Tony D. WilliamsAbstract:Summary 1.Developmental maturity (e.g. body condition, body mass) at major life history transitions is known to affect fitness across a wide range of taxa. 2.Fledging (leaving the nest), a major life-history transition in birds, is associated with high post-Fledging mortality and is widely assumed to be related to poor initial flight ability of fledglings which, in turn, might be related to developmental maturity at Fledging. 3.We investigated individual variation in developmental maturity of both somatic and physiological traits at this critical life history transition in different ecological contexts (year, 1st or 2nd broods) to determine the importance of physiological traits related to oxygen-carrying capacity (hematocrit, hemoglobin) for individual variation in initial flight ability at Fledging. 4.Hemoglobin concentration and hematocrit at Fledging had much higher variance than somatic traits and were more variable across ecological contexts. Furthermore, fledgling hemoglobin concentration was the least developmentally mature of all traits (on average only 78% of adult concentration). 5.Fledglings from 2nd broods, which are known to have lower post-Fledging survival, were less developmentally mature than fledglings from 1st broods for all traits (except tarsus), with hematocrit and hemoglobin concentration being the most developmentally immature traits (in 1st vs. 2nd broods, hematocrit: 47.1% vs. 40.9%; hemoglobin: 13.3 g/dL vs. 11.6 g/dL). 6.Models predicting individual variation in two aspects of initial flight ability (total energy gain, take-off angle) were significantly improved when physiological traits (in particular hemoglobin) were incorporated into models based on somatic traits. This article is protected by copyright. All rights reserved.