Age and foraging success in European blackbirds: variation between and with individuals

Behaving efficiently (optimally or near-optimally) is central to animals' adaptation to their environment. Much evolutionary biology assumes, implicitly or explicitly, that optimal behavioural strategies are genetically inherited, yet the behaviour of many animals depends crucially on learning. The question of how learning contributes to optimal behaviour is largely open. Here we propose an associative learning model that can learn optimal behaviour in a wide variety of ecologically relevant circumstances. The model learns through chaining, a term introduced by Skinner to indicate learning of behaviour sequences by linking together shorter sequences or single behaviours. Our model formalizes the concept of conditioned reinforcement (the learning process that underlies chaining) and is closely related to optimization algorithms from machine learning. Our analysis dispels the common belief that associative learning is too limited to produce ‘intelligent’ behaviour such as tool use, social learning, self-control or expectations of the future. Furthermore, the model readily accounts for both instinctual and learned aspects of behaviour, clarifying how genetic evolution and individual learning complement each other, and bridging a long-standing divide between ethology and psychology. We conclude that associative learning, supported by genetic predispositions and including the oft-neglected phenomenon of conditioned reinforcement, may suffice to explain the ontogeny of optimal behaviour in most, if not all, non-human animals. Our results establish associative learning as a more powerful optimizing mechanism than acknowledged by current opinion.

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“…Reports that foraging efficiency often improves with age support the idea that foraging strategies are partly learned (e.g. [95–97]).…”

Section: Applications To Learning Phenomenamentioning

confidence: 90%

The power of associative learning and the ontogeny of optimal behaviour

2016

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“…For example, individual selection preference based on 100 used trees counted twice as much as one based on only 50 trees. Consequently, each woodpecker individual contributed only 1 degree of freedom in the model regardless of its number of observations (Desrochers 1992). This approach allowed us to use all observations while avoiding pseudo-replication (Machlis et al 1985).…”

Section: Characteristics Of Selected Foraging Substratesmentioning

confidence: 99%

Foraging behavior of the Eurasian Three-toed Woodpecker (Picoides tridactylus) and its implications for ecological restoration and sustainable boreal forest management

Versluijs¹,

Eggers²,

Mikusiński³

et al. 2020

ACE

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Versluijs, M., S. Eggers, G. Mikusiński, J.-M. Roberge, and J. Hjältén. 2020. Foraging behavior of the Eurasian Three-toed Woodpecker (Picoides tridactylus) and its implications for ecological restoration and sustainable boreal forest management. Avian Conservation and Ecology 15(1):6. https:// ABSTRACT. Several studies have shown that the Three-toed Woodpecker (Picoides tridactylus) is strongly favored by large-scale disturbances, including forest fires. However, natural disturbances have largely disappeared from European boreal forests because of modern forestry practices and fire suppression. We currently lack knowledge on the foraging activity and resource use of the Eurasian Three-toed Woodpecker, especially in burned forests, and this restricts our ability to develop strategies for sustainable forest management and ecological restoration aiming at improving the situation of this woodpecker and associated species. In order to fill this knowledge gap, we studied the characteristics of selected foraging substrates and the foraging behavior of the Three-toed Woodpecker during the breeding season in unburned forests and forests that have been subjected to prescribed burning. We used instantaneous sampling during two consecutive springs (2016-2017), where we observed the woodpeckers' foraging behavior during a total of 977 minutes in burned forest and 962 minutes in unburned forests. The preferred foraging substrate for Three-toed Woodpeckers in both burned and unburned forests can be characterized as freshly dead trees with a DBH > 15 cm. However, data on time spent foraging on different substrates suggest that also substrates in the 5-15 DBH range and living trees are important. Additionally, prescribed burnings led to less pronounced selection of tree species, which suggest that fire may reduce differences in abundance of saproxylic insect prey between tree species. This information on substrate selection and foraging time provide complementary knowledge and thus should be used simultaneously when management strategies for improved woodpecker habitat are developed. Our results suggest that both prescribed burning and protecting forests with high density and diversity of dead wood provides habitat opportunities for Three-toed Woodpeckers and using both in management may maximize conservation outcome. Comportement d'alimentation du Pic tridactyle (Picoides tridactylus) et ses implications pour la restauration écologique et les pratiques durables d'aménagement de la forêt boréaleRÉSUMÉ. Plusieurs études ont montré que le Pic tridactyle (Picoides tridactylus) profite des perturbations survenant sur de vastes étendues, dont les incendies de forêt. Toutefois, les perturbations naturelles n'existent presque plus dans les forêts boréales d'Europe en raison des pratiques forestières modernes et de la suppression des incendies de forêt. Le manque actuel de connaissances sur l'alimentation et l'utilisation des ressources par le Pic tridactyle, spécialement dans les forêts brûlées, restreint notre habilité à élaborer des ...

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“…Three nonexclusive hypotheses exist to explain the poorer performance of younger breeders. The first is the constraint hypothesis (Curio 1983), which states that individuals gain experience and skills over the years (e.g., Nol and Smith 1987, Desrochers 1992, De Forest and Gaston 1996. On the other hand, the restraint hypothesis (Curio 1983) suggests that younger breeders that have higher residual reproductive value than older individuals should reduce their reproductive effort to avoid incurring high survival costs (e.g., Ericsson et al 2001, Velando et al 2006).…”

Section: Introductionmentioning

confidence: 99%

From recruitment to senescence: food shapes the age‐dependent pattern of breeding performance in a long‐lived bird

Oro

Hernández

Jover

et al. 2014

Ecology

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We used a long-term data set (26 years) from Audouin's Gull (Larus audouinii), a long-lived seabird, to address the relationship between the age-dependent pattern of reproductive performance and environmental conditions during breeding. Although theoretical models predict that the youngest and oldest breeders (due to inexperience and senescence, respectively) will perform less well than intermediate age classes, few empirical data exist regarding how this expected pattern varies with food availability. To assess the influence of age and food availability (corrected by population size of the main consumers to take into account density dependence) on a number of breeding parameters (laying dates, egg volume, clutch size, and hatching success), we modeled mean and variances of these parameters by incorporating heterogeneity into generalized linear models. All parameters varied with age and to different degrees, depending on food availability. As expected, performance improved with increased food supply, and the observed age pattern was quadratic, with poorer breeding performances occurring in extreme ages. For most parameters (except for laying dates, for which age and food did not interact), the pattern changed with food somewhat unexpectedly; the differences in performance between age classes were higher (i.e., the quadratic pattern was more noticeable) when food was more readily available than when food availability was lower. We suggest that, under poor environmental conditions, only high-quality individuals of the younger and older birds bred and that the differences in breeding performance between age classes were smaller. Although variances for egg volume were constant, variances for laying dates were highest for the youngest breeders and tended to decrease with age, either due to the selection of higher-quality individuals or to a greater frequency of birds skipping breeding with age, especially when food was in low supply. Our results show that mean and variances of breeding parameters changed with age, but that this pattern was different for each parameter and also varied according to food availability. It is likely that, other than food, certain additional factors (e.g., sex, cohort effects, density dependence) also influence changes in breeding performance with age, and this may preclude the finding of a common pattern among traits and among studies on different taxa.

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Age and foraging success in European blackbirds: variation between and with individuals

Cited by 139 publications

References 31 publications

The power of associative learning and the ontogeny of optimal behaviour

The power of associative learning and the ontogeny of optimal behaviour

Foraging behavior of the Eurasian Three-toed Woodpecker (Picoides tridactylus) and its implications for ecological restoration and sustainable boreal forest management

From recruitment to senescence: food shapes the age‐dependent pattern of breeding performance in a long‐lived bird

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