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  • 1
    Online-Ressource
    Online-Ressource
    The Royal Society ; 2020
    In:  Proceedings of the Royal Society B: Biological Sciences Vol. 287, No. 1931 ( 2020-07-29), p. 20201140-
    In: Proceedings of the Royal Society B: Biological Sciences, The Royal Society, Vol. 287, No. 1931 ( 2020-07-29), p. 20201140-
    Kurzfassung: An improved understanding of life-history responses to current environmental variability is required to predict species-specific responses to anthopogenic climate change. Previous research has suggested that cooperation in social groups may buffer individuals against some of the negative effects of unpredictable climates. We use a 15-year dataset on a cooperative breeding arid zone bird, the southern pied babbler Turdoides bicolor , to test (i) whether environmental conditions and group size correlate with survival of young during three development stages (egg, nestling, fledgling) and (ii) whether group size mitigates the impacts of adverse environmental conditions on survival of young. Exposure to high mean daily maximum temperatures (mean T max ) during early development was associated with reduced survival probabilities of young in all three development stages. No young survived when mean T max 〉 38°C, across all group sizes. Low survival of young at high temperatures has broad implications for recruitment and population persistence in avian communities given the rapid pace of advancing climate change. Impacts of high temperatures on survival of young were not moderated by group size, suggesting that the availability of more helpers in a group is unlikely to buffer against compromised offspring survival as average and maximum temperatures increase with rapid anthropogenic climate change.
    Materialart: Online-Ressource
    ISSN: 0962-8452 , 1471-2954
    Sprache: Englisch
    Verlag: The Royal Society
    Publikationsdatum: 2020
    ZDB Id: 1460975-7
    SSG: 12
    SSG: 25
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 2
    Online-Ressource
    Online-Ressource
    Oxford University Press (OUP) ; 2023
    In:  Behavioral Ecology Vol. 34, No. 4 ( 2023-07-10), p. 562-570
    In: Behavioral Ecology, Oxford University Press (OUP), Vol. 34, No. 4 ( 2023-07-10), p. 562-570
    Kurzfassung: Cooperative breeding, where more than two individuals invest in rearing a single brood, occurs in many bird species globally and often contributes to improved breeding outcomes. However, high temperatures are associated with poor breeding outcomes in many species, including cooperative species. We used data collected over three austral summer breeding seasons to investigate the contribution that helpers make to daytime incubation in a cooperatively breeding species, the Southern Pied Babbler Turdoides bicolor, and the ways in which their contribution is influenced by temperature. Helpers spent a significantly higher percentage of their time foraging (41.8 ± 13.7%) and a significantly lower percentage of their time incubating (18.5 ± 18.8%) than members of the breeding pair (31.3 ± 11% foraging and 37.4 ± 15.7% incubating). In groups with only one helper, the helper’s contribution to incubation was similar to that of breeders. However, helpers in larger groups contributed less to incubation, individually, with some individuals investing no time in incubation on a given observation day. Helpers significantly decrease their investment in incubation on hot days ( & gt;35.5°C), while breeders tend to maintain incubation effort as temperatures increase. Our results demonstrate that pied babblers share the workload of incubation unequally between breeders and helpers, and this inequity is more pronounced during hot weather. These results may help to explain why recent studies have found that larger group size does not buffer against the impacts of high temperatures in this and other cooperatively breeding species.
    Materialart: Online-Ressource
    ISSN: 1045-2249 , 1465-7279
    RVK:
    Sprache: Englisch
    Verlag: Oxford University Press (OUP)
    Publikationsdatum: 2023
    ZDB Id: 1496189-1
    SSG: 12
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 3
    Online-Ressource
    Online-Ressource
    Frontiers Media SA ; 2020
    In:  Frontiers in Ecology and Evolution Vol. 8 ( 2020-6-30)
    In: Frontiers in Ecology and Evolution, Frontiers Media SA, Vol. 8 ( 2020-6-30)
    Materialart: Online-Ressource
    ISSN: 2296-701X
    Sprache: Unbekannt
    Verlag: Frontiers Media SA
    Publikationsdatum: 2020
    ZDB Id: 2745634-1
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 4
    In: General and Comparative Endocrinology, Elsevier BV, Vol. 276 ( 2019-05), p. 60-68
    Materialart: Online-Ressource
    ISSN: 0016-6480
    Sprache: Englisch
    Verlag: Elsevier BV
    Publikationsdatum: 2019
    ZDB Id: 1467679-5
    SSG: 12
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 5
    In: Journal of Experimental Biology, The Company of Biologists, Vol. 224, No. 10 ( 2021-05-15)
    Kurzfassung: Relatively little effort has been directed towards elucidating the role of physiological stress pathways in mediating avian responses to global heating. For free-ranging southern pied babblers, Turdoides bicolor, daily maximum air temperatures (Tmax) between ∼35 and ∼40°C result in reduced foraging efficiency, loss of body mass and compromised breeding success. We tested the hypothesis that very hot days are experienced as stressors by quantifying relationships between Tmax and faecal glucocorticoid metabolite (fGCM) levels in naturally excreted droppings. On days when Tmax & lt;38°C, fGCM levels were independent of Tmax (mean±s.d. 140.25±56.92 ng g−1 dry mass). At Tmax & gt;38°C, however, fGCM levels increased linearly with Tmax and averaged 190.79±70.13 ng g−1 dry mass. The effects of Tmax on fGCM levels did not carry over to the following morning, suggesting that very hot days are experienced as acute stressors.
    Materialart: Online-Ressource
    ISSN: 0022-0949 , 1477-9145
    Sprache: Englisch
    Verlag: The Company of Biologists
    Publikationsdatum: 2021
    ZDB Id: 1482461-9
    SSG: 12
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 6
    In: Conservation Physiology, Oxford University Press (OUP), Vol. 9, No. 1 ( 2021-01-01)
    Kurzfassung: High air temperatures have measurable negative impacts on reproduction in wild animal populations, including during incubation in birds. Understanding the mechanisms driving these impacts requires comprehensive knowledge of animal physiology and behaviour under natural conditions. We used a novel combination of a non-invasive doubly labelled water (DLW) technique, nest temperature data and field-based behaviour observations to test effects of temperature, rainfall and group size on physiology and behaviour during incubation in southern pied babblers Turdoides bicolor, a cooperatively breeding passerine endemic to the arid savanna regions of southern Africa. The proportion of time that clutches were incubated declined as air temperatures increased, a behavioural pattern traditionally interpreted as a benefit of ambient incubation. However, we show that (i) clutches had a & lt;50% chance of hatching when exposed to daily maximum air temperatures of & gt;35.3°C; (ii) pied babbler groups incubated their nests almost constantly (99% of daylight hours) except on hot days; (iii) operative temperatures in unattended nests frequently exceeded 40.5°C, above which bird embryos are at risk of death; (iv) pied babblers incubating for long periods of time failed to maintain water balance on hot days; and (v) pied babblers from incubating groups lost mass on hot days. These results suggest that pied babblers might leave their nests during hot periods to lower the risk of dehydration associated with prolonged incubation at high operative temperatures. As mean air temperatures increase and extreme heat events become more frequent under climate change, birds will likely incur ever greater thermoregulatory costs of incubation, leading to compromised nest attendance and increased potential for eggs to overheat, with implications for nest success and, ultimately, population persistence.
    Materialart: Online-Ressource
    ISSN: 2051-1434
    Sprache: Englisch
    Verlag: Oxford University Press (OUP)
    Publikationsdatum: 2021
    ZDB Id: 2721508-8
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 7
    In: Functional Ecology, Wiley, Vol. 33, No. 1 ( 2019-01), p. 162-174
    Kurzfassung: Doubly labelled water ( DLW ) is routinely used to measure energy expenditure and water turnover in free‐ranging animals. Standard methods involve capture, blood sampling for baseline measurement, injection with isotopic tracers, captivity for an equilibration period, post‐dose blood sampling, release and subsequent recapture for final blood sampling. Single sampling methods that minimise disturbance by reducing capture and handling time have been developed and tested. Sampling faeces rather than blood could further reduce disturbance to study animals in a range of species and study systems. However, the extent to which estimates of metabolic rate derived from blood and faecal samples diverge has not been investigated. We compared isotopic enrichment in blood and faecal samples taken concurrently from captive Southern Pied Babblers Turdoides bicolor . Isotopic enrichment levels in faeces and in blood were used to calculate initial and final ratios of for each individual. We then used these ratios to calculate daily energy expenditure ( DEE ) and directly compared measurements from blood samples with those from faecal samples within individuals. We found that faecal sampling resulted in estimates of DEE that agree with those based on blood sampling. Additionally, we field‐tested a faecal sampling protocol with a habituated population of babblers in the southern Kalahari Desert. During the field test, study animals were not captured or handled for either dosing or sampling. Field‐testing confirmed the practical feasibility of non‐invasive dosing and sampling techniques in free‐living animals, and we obtained measurements of DEE that we used to test an a priori prediction that DEE is inversely related to air temperature. Our data show decreasing DEE with increasing air temperature, a pattern consistent with studies testing similar predictions in birds using traditional DLW methods. We demonstrate that faecal samples can substitute for blood when measuring DEE using DLW and provide a method that will allow field‐based researchers to obtain sound physiological measurements while minimising handling and removal of study animals from their natural environments. A plain language summary is available for this article.
    Materialart: Online-Ressource
    ISSN: 0269-8463 , 1365-2435
    URL: Issue
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2019
    ZDB Id: 2020307-X
    ZDB Id: 619313-4
    SSG: 12
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 8
    In: Ibis, Wiley, Vol. 164, No. 1 ( 2022-01), p. 304-312
    Kurzfassung: Sex‐biased mortality in response to environmental adversity during early development occurs in a number of bird species. The three most prominent theories proposed to explain sex‐biased mortality in response to early‐life adversity are that (1) the heterogametic sex (e.g. females in birds), (2) the larger sex (could be male or female depending on species) or (3) the sex with the more costly and complex endocrine system (e.g. males producing higher levels of testosterone) will suffer higher mortality compared with the other sex when exposed to challenging conditions (e.g. suboptimal weather during early development). We tested for sex‐specific differences in the effects of very hot weather on nestling body mass and tarsus length, and survival of fledglings to nutritional independence in the Southern Pied Babbler Turdoides bicolor . The effect of exposure to high air temperatures did not differ by sex but had a consistently negative impact on nestling body mass, nestling tarsus length and fledgling survival, raising concerns about population replacement and the persistence of this species under rapidly advancing climate change.
    Materialart: Online-Ressource
    ISSN: 0019-1019 , 1474-919X
    URL: Issue
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2022
    ZDB Id: 2071870-6
    ZDB Id: 2485031-7
    ZDB Id: 2807-1
    SSG: 12
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 9
    In: Ibis, Wiley
    Kurzfassung: In the southern Kalahari Desert, cooperatively breeding Southern Pied Babblers Turdoides bicolor frequently build their nests and forage in camelthorn trees Vachellia erioloba , a keystone species in the region, and blackthorn trees Senegalia mellifera , a widespread early successional shrub. Using Ivlev's electivity indices (Ei), we show that Southern Pied Babblers preferentially nest in camelthorn trees and preferentially forage in or under camelthorn and blackthorn trees. Southern Pied Babblers primarily forage on the ground; however, they will make use of arboreal resources when these are available. We observed the birds spending the highest proportion of foraging time off the ground during October, when breeding is also most common, compared with all other months within the austral summer breeding season. They are most likely to be observed foraging in camelthorn trees earlier in the breeding season and blackthorn trees later in the breeding season. We demonstrate that Southern Pied Babblers have a strong relationship with camelthorn trees, in which they prefer to both nest and forage. We highlight the importance of protecting camelthorn trees, a keystone species in the region, as part of the conservation and management of endemic Kalahari fauna such as the Southern Pied Babbler. In addition to contributing to the literature on keystone species, our observations raise questions about the ways in which avian reproduction in the arid zone could be decoupled from rainfall via the phenology of deep‐rooted tree species.
    Materialart: Online-Ressource
    ISSN: 0019-1019 , 1474-919X
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2023
    ZDB Id: 2071870-6
    ZDB Id: 2485031-7
    ZDB Id: 2807-1
    SSG: 12
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 10
    In: Ecology Letters, Wiley, Vol. 23, No. 12 ( 2020-12), p. 1776-1788
    Kurzfassung: Climate change is affecting animal populations around the world and one relatively unexplored aspect of species vulnerability is whether and to what extent responses to environmental stressors might be mitigated by variation in group size in social species. We used a 15‐year data set for a cooperatively breeding bird, the southern pied babbler Turdoides bicolor , to determine the impact of temperature, rainfall and group size on body mass change and interannual survival in both juveniles and adults. Hot and dry conditions were associated with reduced juvenile growth, mass loss in adults and compromised survival between years in both juveniles (86% reduction in interannual survival) and adults (60% reduction in interannual survival). Individuals across all group sizes experienced similar effects of climatic conditions. Larger group sizes may not buffer individual group members against the impacts of hot and dry conditions, which are expected to increase in frequency and severity in future.
    Materialart: Online-Ressource
    ISSN: 1461-023X , 1461-0248
    URL: Issue
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2020
    ZDB Id: 2020195-3
    SSG: 12
    Standort Signatur Einschränkungen Verfügbarkeit
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