Ravens respond to unfamiliar corvid alarm calls

Davídková, Marika; Veselý, Petr; Syrová, Michaela; Nácarová, Jana; Bugnyar, Thomas

doi:10.1007/s10336-020-01781-w

Cited by 4 publications

(4 citation statements)

References 30 publications

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“…Such assessment capability by receivers was also documented in small mammals, precisely in adult Richardson´s ground squirrels (Sloan & Hare, 2008). When confronted with alarm calls from conspecifics and closely related heterospecifics during foraging, carrion crows tended to respond to any alarm calls (Bílá, Beránková, Veselý, Bugnyar, & Schwab, 2017), whereas ravens adjusted their antipredator behaviour depending on the perceived risk (whether or not they snatched food from predators; Nácarová, Veselý, & Bugnyar, 2018) and the familiarity of the calling species (Davidkova, Veselý, Syrova, Nacarovà, & Bugnyar, 2020).…”

Section: Introductionmentioning

confidence: 83%

Who is crying wolf? Seasonal effect on antipredator response to age-specific alarm calls in common ravens, Corvus corax

2021

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Communication about threats including those posed by the presence of predators occurs mainly through acoustic signals called alarm calls. The comprehension of these calls by receivers and their rapid antipredator response are crucial in terms of survival. However, to avoid overreaction, individuals should evaluate whether or not an antipredator response is needed by paying attention to who is calling. For instance, we could expect adults to be more experienced with predator encounters than juveniles and thus elicit stronger antipredator responses in others when alarming. Similarly, we could expect a stronger response to alarm calls when more than one individual is calling. To test these assumptions, we applied a playback experiment to wild ravens, in which we manipulated the age class (adult or juvenile) and the number (one or two) of the callers. Our results revealed a seasonal effect of age class but no effect of number of callers. Specifically, the ravens responded with stronger antipredator behaviour (vigilance posture) towards alarm calls from adults as compared to juveniles in summer and autumn, but not in spring. We discuss alternative interpretations for this unexpected seasonal pattern and argue for more studies on call-based communication in birds to understand what type of information is relevant under which conditions.

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Section: Introductionmentioning

confidence: 83%

Who is crying wolf? Seasonal effect on antipredator response to age-specific alarm calls in common ravens, Corvus corax

2021

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“…If receiver species differ in which of these features they recognise, then the more species presenting information, the more information that can be used (as suggested by Carlson et al ., 2020 b ). The ways that receivers may process information could be related to their own conspecific use of signals: some animal species may respond more strongly to alarm calls that are similar to conspecific alarms (Dalesman et al ., 2007; Randler, 2012; Magrath et al ., 2015 a ; Meise, Franks & Bro‐Jørgensen, 2018; Davídková et al ., 2020). Likewise, plant responses to volatile chemicals induced by herbivore damage tend to be evolutionarily conserved.…”

Section: Increased and Better Information With Higher Species Diversitymentioning

confidence: 99%

Species diversity and interspecific information flow

Goodale,

Magrath

2024

Biological Reviews

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Interspecific information flow is known to affect individual fitness, population dynamics and community assembly, but there has been less study of how species diversity affects information flow and thereby ecosystem functioning and services. We address this question by first examining differences among species in the sensitivity, accuracy, transmissibility, detectability and value of the cues and signals they produce, and in how they receive, store and use information derived from heterospecifics. We then review how interspecific information flow occurs in communities, involving a diversity of species and sensory modes, and how this flow can affect ecosystem‐level functions, such as decomposition, seed dispersal or algae removal on coral reefs. We highlight evidence that some keystone species are particularly critical as a source of information used by eavesdroppers, and so have a disproportionate effect on information flow. Such keystone species include community informants producing signals, particularly about predation risk, that influence other species' landscapes of fear, and aggregation initiators creating cues or signals about resources. We suggest that the presence of keystone species means that there will likely be a positive relationship in many communities between species diversity and information through a ‘sampling effect’, in which larger pools of species are more likely to include the keystone species by chance. We then consider whether the number and relative abundance of species, irrespective of the presence of keystone species, matter to interspecific information flow; on this issue, the theory is less developed, and the evidence scant and indirect. Higher diversity could increase the quantity or quality of information that is used by eavesdroppers because redundancy increases the reliability of information or because the species provide complementary information. Alternatively, there could be a lack of a relationship between species diversity and information if there is widespread information parasitism where users are not sources, or if information sourced from heterospecifics is of lower value than that gained personally or sourced from conspecifics. Recent research suggests that species diversity does have information‐modulated community and ecosystem consequences, especially in birds, such as the diversity of species at feeders increasing resource exploitation, or the number of imitated species increasing responses to vocal mimics. A first step for future research includes comprehensive observations of information flow among different taxa and habitats. Then studies should investigate whether species diversity influences the cumulative quality or quantity of information at the community level, and consequently ecosystem‐level processes. An applied objective is to conserve species in part for their value as sources of information for other species, including for humans.

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“…Frid and Dill (2002) suggested that "disturbance stimuli should be analogous to predation risk" and list vigilance as a response to disturbance. These disturbance stimuli include vocalizations of other species, as eavesdropping on heterospecific vocalizations allows individuals to detect the presence of a predator (Magrath et al, 2015).Common ravens (Corvus corax), for instance, respond to playback of jackdaw (Corvus monedula), blue jay (Cyanocitta cristata), European jay (Garrulus glandarius), and laughing gull (Leucophaeus atricilla) alarm calls with flight or vigilance (Davídková et al, 2020;Nácarová et al, 2018).…”

Section: Eavesdropping On Speechmentioning

confidence: 99%

Differential Survival In Carrion Crows Through Eavesdropping on Human Speech: An Agent-Based Model

Schalz

2023

Preprint

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Wild carrion crows eavesdrop on human speech and respond more strongly to it than to the calls of pigeons or parakeets. However, it remains unclear whether this behaviour provides any benefit to them, and if so, under which environmental conditions such a benefit could be expected. I used an agent-based model to examine the effect of eavesdropping on the survival of a carrion crow under different environmental conditions. The crow could gain points from foraging, but also had to avoid encounters with a human in order to not lose points. In addition to eavesdropping, it could visually scan the patch for human presence and, once detected, could keep track of the humans location. I found that eavesdropping led to higher final scores and higher rates of survival than visual scanning alone if the human density on the patch was elevated, or if there were visual obstacles reducing the accuracy of visual scans. Such environmental conditions are particularly common for urban crows foraging in areas such as public parks. The model provides a proof of concept for future empirical research into the potentially differential survival of urban crows eavesdropping on speech.

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Ravens respond to unfamiliar corvid alarm calls

Cited by 4 publications

References 30 publications

Who is crying wolf? Seasonal effect on antipredator response to age-specific alarm calls in common ravens, Corvus corax

Who is crying wolf? Seasonal effect on antipredator response to age-specific alarm calls in common ravens, Corvus corax

Species diversity and interspecific information flow

Differential Survival In Carrion Crows Through Eavesdropping on Human Speech: An Agent-Based Model

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