Factors Affecting Sleep/vigilance Behaviour in Incubating Mallards

Javůrková, Veronika; Hořák, David; Kreisinger, Jakub; Klvaňa, Petr; Albrecht, Tomáš

doi:10.1111/j.1439-0310.2011.01878.x

Cited by 17 publications

(22 citation statements)

References 59 publications

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“…Use of the behaviour varies with time of day (Javůrková et al . ) and season (Midtgård ). However, there have been no extensive studies of the frequency of this specific behaviour in relation to ambient temperature in wild bird populations, although Brodsky & Weatherhead () identified it as one of a number of behaviours that black ducks ( Anas rubripes ) adopt on very cold days.…”

Section: Introductionmentioning

confidence: 99%

Bill size mediates behavioural thermoregulation in birds

2017

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Summary Bird bills have been the subject of classic evolutionary studies that demonstrate how morphological adaptations are driven by foraging ecology. As significant areas of heat loss, bills are also under selection with respect to thermoregulation, yet the ecological consequences of this function have been largely ignored until recently. Given the role of bills in thermoregulation is important, we predict that birds should behave to minimise heat loss through their bills at lower ambient temperatures by attempting to insulate their bill in their plumage. Our second prediction is that this thermoregulatory behaviour should be utilised more by species with relatively larger bills, because they will be more prone to heat loss. We demonstrate both these predictions to be correct using field observations and a comparative analysis of nine shorebird species. First, the placement of the bill within the back plumage while roosting (‘back rest’ behaviour), which insulates the bill, becomes more frequent at cooler temperatures. Second, species with large bills relative to their body size do indeed use back rest behaviour more frequently across a range of temperatures. Our findings show that behavioural thermoregulation can be mediated by bill size, and that bill morphology is not only relevant to foraging ecology but also influences behavioural adaptations to climate. A http://onlinelibrary.wiley.com/doi/10.1111/1365-2435.12814/suppinfo is available for this article.

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Section: Introductionmentioning

confidence: 99%

Bill size mediates behavioural thermoregulation in birds

2017

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“…Ambient temperature and wind speed were recorded at 5-min intervals (and averaged) during each video bout (taken as close to the birds as possible without causing disturbance) using a Kestrel 3000 pocket weather meter (Nielsen-Kellerman Company, Boothwyn, PA, USA). Ambient temperature has been shown in previous studies to effect the use of thermoregulatory behaviours (Midtgård 1978, Anderson and Williams 2010, Bouchard and Anderson 2011, Javůrková et al 2011, Ryeland et al 2017, Yorzinski et al 2018 and is therefore appropriate to use here. Furthermore, gaining operative or microclimate temperature would cause disturbance to the birds, which would result in modification of behaviours.…”

Section: Observations Of Shorebird Behaviourmentioning

confidence: 99%

“…The covering of bare appendages generally increases with decreasing ambient temperature (Amlaner andBall 1983, Ryeland et al 2017). For example, placing the bill back and within the plumage, and standing on one leg occurs more at low ambient temperatures, across all temperatures studied (Midtgård 1978, Anderson and Williams 2010, Bouchard and Anderson 2011, Javůrková et al 2011, Ryeland et al 2017, Yorzinski et al 2018.…”

Section: Introductionmentioning

confidence: 99%

Leg length and temperature determine the use of unipedal roosting in birds

Ryeland

Weston

Symonds

2019

Journal of Avian Biology

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The function of standing on one leg in birds has long been attributed to reducing heat loss from the unfeathered legs to the external environment. Whilst a handful of single‐species studies correlate the use of the behaviour with ambient temperature, the degree to which it is used across taxa is unknown. Given that leg‐length varies between species, the length of the leg (relative to body size) may mediate the use of this thermoregulatory behaviour, such that birds with longer legs should roost on one leg more than those with relatively shorter legs at any given ambient temperature. We tested this prediction through field observations and comparative analyses of nine shorebird species, with varying tarsi length relative to body size. Six of the nine species examined used unipedal standing more as temperatures decrease, indicating its role as a heat conservation behaviour. We also found that species with relatively longer legs roosted on one leg more frequently across a wide range of temperatures. Species with shorter leg lengths likely rely less on this posture to insulate the relatively smaller surface area of the legs. Our findings showed that the long accepted notion that birds stand on one leg more at colder temperatures holds, and that species with smaller relative leg length were less reliant on this behaviour to minimise heat loss from these bare appendages.

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“…; Javurkova et al. ) and may thus provide a good measure of vigilance. Based on the above theory, we predicted that the proportion of sleeping birds in loafing groups would increase through time, reflecting the lower perception of predation risk when gulls are not harassed by potential cruising predators such as bald eagles ( Haliaeetus leucocephalus ) or disturbed by people.…”

Section: Introductionmentioning

confidence: 99%

“…Sleeping can be characterized as a low vigilance state because even though sleeping gulls open their eyes periodically, their reaction time to external events is substantially diminished relative to alert individuals (Amlaner & McFarland 1981). Adjustments in sleeping have been related to variation in predation risk in other species (Rattenborg et al 1999;Mathews et al 2006;Javurkova et al 2011) and may thus provide a good measure of vigilance. Based on the above theory, we predicted that the proportion of sleeping birds in loafing groups would increase through time, reflecting the lower perception of predation risk when gulls are not harassed by potential cruising predators such as bald eagles (Haliaeetus leucocephalus) or disturbed by people.…”

Section: Introductionmentioning

confidence: 99%

Vigilance Decreases with Time at Loafing Sites in Gulls (Larus spp.)

Beauchamp

Ruxton

2012

Ethology

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Understanding how animals partition effort between vigilance for predators and other conflicting activities has been a mainstay of animal behaviour research. Classical theories implicitly assume that animals alternate between high and low vigilance states over short timescales, but that average effort invested in vigilance is constant over an extended bout of such alternations. However, one recent model suggests that vigilance should be adjusted dynamically to short‐term changes in the perception of predation risk and would tend to decrease with time. Indeed, as time passes by without disturbances, perception of the need for vigilance should decrease and prey animals may allocate more time to competing activities. Here, we examined how the proportion of sleeping gulls (Larus spp.) in loafing groups changed over time. Sleeping gulls can only maintain low levels of vigilance against external threats (compared to alert individuals), and we predicted that the proportion of sleeping gulls at loafing sites should increase over time when no disturbances occur. Statistically significant changes in the proportion of sleeping gulls as a function of time occurred in the majority of sequences and an increase was observed significantly more often than predicted by chance alone. This temporal pattern cannot be caused by reduction in hunger levels because gulls are not feeding at loafing sites. The results indicate that vigilance can be adjusted dynamically in response to short‐term temporal changes in the perception of predation risk.

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Factors Affecting Sleep/vigilance Behaviour in Incubating Mallards

Cited by 17 publications

References 59 publications

Bill size mediates behavioural thermoregulation in birds

Bill size mediates behavioural thermoregulation in birds

Leg length and temperature determine the use of unipedal roosting in birds

Vigilance Decreases with Time at Loafing Sites in Gulls (Larus spp.)

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