The Experts below are selected from a list of 306 Experts worldwide ranked by ideXlab platform
Ryan J Fisher - One of the best experts on this subject based on the ideXlab platform.
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Nest Site attributes and temporal patterns of northern flicker Nest loss effects of predation and competition
Oecologia, 2006Co-Authors: Ryan J Fisher, Karen L WiebeAbstract:To date, most studies of Nest Site selection have failed to take into account more than one source of Nest loss (or have combined all sources in one analysis) when examining Nest Site characteristics, leaving us with an incomplete understanding of the potential trade-offs that individuals may face when selecting a Nest Site. Our objectives were to determine whether northern flickers (Colaptes auratus) may experience a trade-off in Nest Site selection in response to mammalian Nest predation and Nest loss to a cavity Nest competitor (European starling, Sturnus vulgaris). We also document within-season temporal patterns of these two sources of Nest loss with the hypothesis that flickers may also be constrained in the timing of reproduction under both predatory and competitive influence. Mammalian predators frequently depredated flicker Nests that were: lower to the ground, less concealed by vegetation around the cavity entrance and at the base of the Nest tree, closer to coniferous forest edges and in forest clumps with a high percentage of conifer content. Proximity to coniferous edges or coniferous trees increased the probability of Nest predation, but Nests near conifers were less likely to be lost to starlings. Flickers may thus face a trade-off in Nest Site selection with respect to safety from predators or competitors. Models suggested that peaks of Nest predation and Nest loss to eviction occurred at the same time, although a competing model suggested that the peak of Nest loss to starlings occurred 5 days earlier than the peak of mammalian predation. Differences in peaks of mammalian predation and loss to starlings may constrain any adjustment in clutch initiation date by flickers to avoid one source of Nest loss.
Karen L Wiebe - One of the best experts on this subject based on the ideXlab platform.
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Nest Site attributes and temporal patterns of northern flicker Nest loss effects of predation and competition
Oecologia, 2006Co-Authors: Ryan J Fisher, Karen L WiebeAbstract:To date, most studies of Nest Site selection have failed to take into account more than one source of Nest loss (or have combined all sources in one analysis) when examining Nest Site characteristics, leaving us with an incomplete understanding of the potential trade-offs that individuals may face when selecting a Nest Site. Our objectives were to determine whether northern flickers (Colaptes auratus) may experience a trade-off in Nest Site selection in response to mammalian Nest predation and Nest loss to a cavity Nest competitor (European starling, Sturnus vulgaris). We also document within-season temporal patterns of these two sources of Nest loss with the hypothesis that flickers may also be constrained in the timing of reproduction under both predatory and competitive influence. Mammalian predators frequently depredated flicker Nests that were: lower to the ground, less concealed by vegetation around the cavity entrance and at the base of the Nest tree, closer to coniferous forest edges and in forest clumps with a high percentage of conifer content. Proximity to coniferous edges or coniferous trees increased the probability of Nest predation, but Nests near conifers were less likely to be lost to starlings. Flickers may thus face a trade-off in Nest Site selection with respect to safety from predators or competitors. Models suggested that peaks of Nest predation and Nest loss to eviction occurred at the same time, although a competing model suggested that the peak of Nest loss to starlings occurred 5 days earlier than the peak of mammalian predation. Differences in peaks of mammalian predation and loss to starlings may constrain any adjustment in clutch initiation date by flickers to avoid one source of Nest loss.
C. Hoi - One of the best experts on this subject based on the ideXlab platform.
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Traditional versus non-traditional Nest-Site choice: alternative decision strategies for Nest-Site selection
Oecologia, 2011Co-Authors: Herbert Hoi, Anton Kristin, Francisco Valera, C. HoiAbstract:In order to understand habitat selection, it is important to consider the way individual animals assess the suitability of a future reproductive Site. One way of investigating mechanisms (such as those involved in Nest Site selection) is to examine breeding success and habitat characteristics in terms of animals returning to a place where they have already reproduced and using the same location over successive years or searching for new alternatives. This approach seems especially suitable for testing recent hypotheses suggesting that Nest Site selection is an integrative process that includes the use of social information (e.g. past breeding success of conspecifics). Determining the factors that elicit conservative or innovative behaviour regarding Nest-Site selection could be important for improving our understanding of habitat selection decisions in animals. More than half of the Nests of the long-distance migratory lesser grey shrike Lanius minor, are built in the same or neighbouring trees. We found no evidence that habitat characteristics influence Nest-Site tradition. On the contrary, social information in terms of the presence of conspecifics and past reproductive success in terms of complete Nest failures due to Nest predation (but not detailed information such as variation in fledgling number) influenced Nest-Site tradition. Hence, social information and past reproductive success may play a role in Nest-Site choice in this species. Our results further demonstrate that previous experience with a Nest Site does not appear to be beneficial.
Thomas E Martin - One of the best experts on this subject based on the ideXlab platform.
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the influence of Nest Site characteristics on the Nesting success of the karoo prinia prinia maculosa
Ostrich, 2004Co-Authors: Dianah Nalwanga, Penn Lloyd, Morné A. Du Plessis, Thomas E MartinAbstract:Choice of Nest Site has important consequences for Nest survival. We examined Nest-Site characteristics relative to Nest success in Karoo Prinias breeding in coastal dwarf shrubland, where high Nest predation is the main cause of Nest failure. Initially, we compared Nests that failed during the building, laying, incubation and Nestling stages and those from which young were successfully raised, to test whether Nests that survived to progressive stages in the Nesting cycle differed in their Nest-Site characteristics. Subsequently, we compared the characteristics of successful Nests with those of unsuccessful Nests. The Nest-Site characteristics considered included Nest height, Nest-plant height, Nest-plant species, distance from lateral foliage edge, Nest concealment, Nest-patch heterogeneity and vegetation cover at four different heights. We were unable to distinguish between the Nest-Site characteristics of Nests that failed during the various stages of the Nesting cycle. Concealment was the main Nest-si...
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Nest-Site preference and maternal effects on offspring growth
Behavioral Ecology, 2004Co-Authors: John D. Lloyd, Thomas E MartinAbstract:Maternal preferences for oviposition Sites are assumed to be adaptive, but offspring fitness is not always higher at preferred Sites and, thus, further study of the selection pressures that influence oviposition behavior is warranted. Among birds, predation is regarded as the primary agent of selection on Nest-Site microhabitat preferences, but alternatives are rarely considered. We tested the hypothesis that avian Nest-Site preferences are an adaptive response to fitness costs imposed by variation in Nest-Site microclimate. We documented that Chestnut-collared Longspurs (Calcarius ornatus) strongly preferred to orient Nests towards the southeast and showed that this preference influenced microclimate: Nests facing southeast had the highest midday temperatures. Yet, preferences were not adaptive because Nestlings in Nests with the preferred orientation gained mass at a slower rate, had retarded skeletal growth, and reached a smaller final size. We experimentally tested this result by altering orientation of Nests and confirmed, for the first time, that variation in Nestling growth was causally linked to variation in Nest microclimate arising from Nest-orientation preferences. Adults responded to the high temperatures at preferred southeast-facing Nests by spending more time shading young from the sun, apparently attempting to ameliorate heat costs. This response, however, resulted in parents spending less time feeding young, potentially explaining slower growth in these Nests. Direct effects of higher temperatures may also play a role in slower growth. Although we lack an explanation for this apparently maladaptive preference, these results demonstrate that Nest-Site choices of birds can yield fitness costs imposed by variation in Nest microclimate. Key words: Calcarius ornatus, grassland bird, maternal effects, Nest microclimate, Nest-Site selection, Nestling growth. [Behav Ecol 15:816–823 (2004)]
David A. Pike - One of the best experts on this subject based on the ideXlab platform.
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Effects of intraguild predators on Nest-Site selection by prey
Oecologia, 2012Co-Authors: Wen-san Huang, David A. PikeAbstract:Nest-Site selection involves tradeoffs between the risk of predation (on females and/or Nests) and Nest-Site quality (microenvironment), and consequently suitable Nesting Sites are often in limited supply. Interactions with “classical” predators (e.g., those not competing for shared resources) can strongly influence Nest-Site selection, but whether intraguild predation also influences this behavior is unknown. We tested whether risk of predation from an intraguild predator [the diurnal scincid lizard Eutropis ( Mabuya ) longicaudata ] influences Nest-Site selection by its prey (the nocturnal gecko Gekko hokouensis ) on Orchid Island, Taiwan. These two species putatively compete for shared resources, including invertebrate prey and Nesting microhabitat, but the larger E. longicaudata also predates G. hokouensis (but not its hard-shelled eggs). Both species Nested within a concrete wall containing a series of drainage holes that have either one (“closed-in”) or two openings (“open”). In allopatry, E. longicaudata preferred to Nest within holes that were plugged by debris (thereby protecting eggs from water intrusion), whereas G. hokouensis selected holes that were open at both ends (facilitating escape from predators). When we experimentally excluded E. longicaudata from its preferred Nesting area, G. hokouensis not only Nested in higher abundances, but also modified its Nest-Site selection, such that communal Nesting was more prevalent and both open and closed-in holes were used equally. Egg viability was unaffected by the choice of hole type, but was reduced slightly (by 7%) in the predator exclusion area (presumably due to higher local incubation temperatures). Our field experiment demonstrates that intraguild predators can directly influence the Nest density of prey by altering maternal Nest-Site selection behavior, even when the predator and prey are active at different times of day and the eggs are not at risk of predation.
