Jakub Szymkowiak

Facing Uncertainty: How Small Songbirds Acquire and Use Social Information in Habitat Selection Process?

Habitat selection is a decision-making process that birds use to select a habitat in which they live. It is crucial for individuals to make the correct choices, because their living space directly affects their fitness. When making settlement decisions, birds are faced with uncertainty about habitat quality. In order to reduce it, they have to acquire information, which makes their world more predictable. Acquisition and use of information about habitat quality is the central part of the habitat selection process. Individuals can acquire information about habitat quality in various ways, e.g., by using own breeding experience (personal information), or by observing behavior and decisions made by other individuals (social information). In this review I briefly described the types of social information which songbirds use to assess the habitat quality. By using unified approach, I evaluated their value and availability for individuals, concluding that simultaneous use of several types of information provide the most effective way to habitat quality assessment. Furthermore, I argued why tits (Paridae) constitute a crucial link in the chain of interspecific social information transfer within songbirds’ communication networks throughout the Holarctic and suggested that they may be considered as the keystone cue-providers. Moreover, I evaluated current literature on the artificial-attraction methods and highlighted urgent research needs in context of its practical application in the conservation and management of songbirds populations.

Interspecific social information use in habitat selection decisions among migrant songbirds

Lay Summary A late arriving migrant bird species (wood warbler) are attracted to simulated presence of an earlier arriving species (chiffchaff). This habitat selection strategy was previously only described for migrants attracting to resident species, but we show that using other species as cues for good breeding sites also occurs between migrants. Wood warblers use a combination of personal information, and cues based on individuals of the same and different species to make settlement decisions.Twitter: @szymkowiakj

Predation-related costs and benefits of conspecific attraction in songbirds--an agent-based approach.

Songbirds that follow a conspecific attraction strategy in the habitat selection process prefer to settle in habitat patches already occupied by other individuals. This largely affects the patterns of their spatio-temporal distribution and leads to clustered breeding. Although making informed settlement decisions is expected to be beneficial for individuals, such territory clusters may potentially provide additional fitness benefits (e.g., through the dilution effect) or costs (e.g., possibly facilitating nest localization if predators respond functionally to prey distribution). Thus, we hypothesized that the fitness consequences of following a conspecific attraction strategy may largely depend on the composition of the predator community. We developed an agent-based model in which we simulated the settling behavior of birds that use a conspecific attraction strategy and breed in a multi-predator landscape with predators that exhibited different foraging strategies. Moreover, we investigated whether Bayesian updating of prior settlement decisions according to the perceived predation risk may improve the fitness of birds that rely on conspecific cues. Our results provide evidence that the fitness consequences of conspecific attraction are predation-related. We found that in landscapes dominated by predators able to respond functionally to prey distribution, clustered breeding led to fitness costs. However, this cost could be reduced if birds performed Bayesian updating of prior settlement decisions and perceived nesting with too many neighbors as a threat. Our results did not support the hypothesis that in landscapes dominated by incidental predators, clustered breeding as a byproduct of conspecific attraction provides fitness benefits through the dilution effect. We suggest that this may be due to the spatial scale of songbirds’ aggregative behavior. In general, we provide evidence that when considering the fitness consequences of conspecific attraction for songbirds, one should expect a trade-off between the benefits of making informed decisions and the costs of clustering.

Threat-sensitive anti-predator defence in precocial wader, the northern lapwing Vanellus vanellus

Birds exhibit various forms of anti-predator behaviours to avoid reproductive failure, with mobbing—observation, approach and usually harassment of a predator—being one of the most commonly observed. Here, we investigate patterns of temporal variation in the mobbing response exhibited by a precocial species, the northern lapwing (Vanellus vanellus). We test whether brood age and self-reliance, or the perceived risk posed by various predators, affect mobbing response of lapwings. We quantified aggressive interactions between lapwings and their natural avian predators and used generalized additive models to test how timing and predator species identity are related to the mobbing response of lapwings. Lapwings diversified mobbing response within the breeding season and depending on predator species. Raven Corvus corax, hooded crow Corvus cornix and harriers evoked the strongest response, while common buzzard Buteo buteo, white stork Ciconia ciconia, black-headed gull Chroicocephalus ridibundus and rook Corvus frugilegus were less frequently attacked. Lapwings increased their mobbing response against raven, common buzzard, white stork and rook throughout the breeding season, while defence against hooded crow, harriers and black-headed gull did not exhibit clear temporal patterns. Mobbing behaviour of lapwings apparently constitutes a flexible anti-predator strategy. The anti-predator response depends on predator species, which may suggest that lapwings distinguish between predator types and match mobbing response to the perceived hazard at different stages of the breeding cycle. We conclude that a single species may exhibit various patterns of temporal variation in anti-predator defence, which may correspond with various hypotheses derived from parental investment theory.