Opportunistic predation reveals a hidden cost of fighting in birds

Diniz, Pedro

doi:10.1007/s43388-020-00020-3

Cited by 9 publications

(2 citation statements)

References 30 publications

(37 reference statements)

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“…Such an increase in capture probability is possible owing to fatigue of the prey, its injury, if it is slowed down, or if failed capture attempts attract the attention of other predators nearby or increase their vigilance. It is no surprise that fatigue or injury increases predation risk (Ota 2018, Diniz 2020), or that predation success of ambush predators decreases with increasing movement speed of the prey (Van Damme and Van Dooren 1999, Clemente and Wilson 2016). In addition, injury impairs the prey's movement or maneuverability, which leads to higher predation success (Downes and Shine 2001, Krause et al 2017).…”

Section: Discussionmentioning

confidence: 99%

Four scenarios in which shadow competition should be prominent and factors affecting its strength

Scharf,

Ruxton

2023

Oikos

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Shadow competition is the interception of moving prey by a predator closer to its arrival source, preventing its availability to predators downstream. Shadow competition is likely common in nature, and unlike some other competition types, has a strong spatial component (with the exception of competition for space, which clearly also has a spatial component). We used an individual‐based spatially‐explicit simulation model to examine whether shadow competition takes place and which factors affect it in four scenarios considering ambush predators and active prey. First, when prey capture is uncertain (‘the ricochet effect'). Here, the strength of shadow competition increases when it is harder to capture prey after the first unsuccessful capture attempt, whereas shadow competition is moderated if capture success is higher in successive attempts. Second, shadow competition becomes stronger when predators can capture prey arriving only from certain directions. Third, when prey tend to move along a barrier after encountering it. Here, predators located along this barrier may be more successful than those at random positions, but shadow competition in this scenario drastically decreases the capture success of predators in central positions along a barrier (i.e. having more than a single neighbor). Finally, in three‐level systems of plants in clusters, herbivores searching for plants, and predators ambushing herbivores inside plant patches, predators with ambush locations in the periphery of plant patches are more successful than those at the patch center, especially at high predator densities. Our simulation indicates that shadow competition is plausibly relevant in various scenarios of ambush predators and prey, and that it varies based on the habitat structure and capture probability of prey by predators as well as the change in capture probability with successive encounters.

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Section: Discussionmentioning

confidence: 99%

Four scenarios in which shadow competition should be prominent and factors affecting its strength

Scharf,

Ruxton

2023

Oikos

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“…Aggressive behaviors help individuals to gain access to and defend resources such as food, territories, mates, nesting sites, display sites, and roosting sites. These behaviors, however, can be costly when aggressive encounters escalate to physical battles, which can be energetically demanding ( e.g ., Riechert, 1988 ; Rovero et al, 2000 ; deCarvalho, Watson & Field, 2004 ; Briffa & Sneddon, 2007 ; Viera et al, 2011 ) and result in increased predation risk ( e.g ., Jakobsson, Brick & Kullberg, 1995 ; Diniz, 2020 ), injury ( e.g ., Robertson, Gibbs & Stuchbury, 1986 ), or death ( e.g ., Hof & Hazlett, 2012 ; Lowney et al, 2017 ; Guo & Dukas, 2020 ). Individuals can settle disputes without incurring these costs by instead signaling during aggressive encounters.…”

Section: Introductionmentioning

confidence: 99%

Aggressive signaling among competing species of birds

Kenyon¹,

Martin²

2022

PeerJ

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Aggressive interactions help individuals to gain access to and defend resources, but they can be costly, leading to increased predation risk, injury, or death. Signals involving sounds and color can allow birds to avoid the costs of intraspecific aggressive encounters, but we know less about agonistic signaling between species, where fights can be frequent and just as costly. Here, we review photographic and video evidence of aggressive interactions among species of birds (N = 337 interactions documenting the aggressive signals of 164 different bird species from 120 genera, 50 families, and 24 orders) to document how individuals signal in aggressive encounters among species, and explore whether these visual signals are similar to those used in aggressive encounters with conspecifics. Despite the diversity of birds examined, most aggressively signaling birds displayed weapons (bills, talons, wings) used in fighting and placed these weapons closest to their heterospecific opponent when signaling. Most species oriented their bodies and heads forward with their bills pointing towards their heterospecific opponent, often highlighting their face, throat, mouth, and bill. Many birds also opened their wings and/or tails, increasing their apparent size in displays, consistent with the importance of body size in determining behavioral dominance among species. Aggressive postures were often similar across species and taxonomic families. Exceptions included Accipitridae and Falconidae, which often highlighted their talons in the air, Columbidae, which often highlighted their underwings from the side, and Trochilidae, which often hovered upright in the air and pointed their fanned tail downward. Most species highlighted bright carotenoid-based colors in their signals, but highlighted colors varied across species and often involved multiple colors in combination (e.g., black, white, and carotenoid-based colors). Finally, birds tended to use the same visual signals in aggressive encounters with heterospecifics that they use in aggressive encounters with conspecifics, suggesting that selection from aggressive interactions may act on the same signaling traits regardless of competitor identity.

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