Beak shape and nest material use in birds

The evolution of behaviour can both influence, and be influenced by, morphology. Recent advances in methods and data availability have facilitated broad-scale investigations of physical form and behavioural function in many contexts, but the relationship between animal morphology and object manipulation—particularly objects used in construction—remains largely unknown. Here, we employ a new global database of nest materials used by 5924 species of birds together with phylogenetically informed random forest models to evaluate the link between beak shape and these nest-building materials. We find that beak morphology, together with species diet and access to materials, can predict nest-material use above chance and with high accuracy (68–97%). Much of this relationship, however, is driven by phylogenetic signal and sampling biases. We therefore conclude that while variation in nest material use is linked with that of beak shape across bird species, these correlations are modulated by the ecological context and evolutionary history of these species.This article is part of the theme issue ‘The evolutionary ecology of nests: a cross-taxon approach’

Anthropogenic nest material use in a global sample of birds

As humans increasingly modify the natural world, many animals have responded by changing their behaviour. Understanding and predicting the extent of these responses is a key step in conserving these species. For example, the tendency for some species of birds to incorporate anthropogenic items—particularly plastic material—into their nests is of increasing concern, as in some cases, this behaviour has harmful effects on adults, young and eggs. Studies of this phenomenon, however, have to date been largely limited in geographic and taxonomic scope. To investigate the global correlates of anthropogenic (including plastic) nest material use, we used Bayesian phylogenetic mixed models and a data set of recorded nest materials in 6147 species of birds. We find that, after controlling for research effort and proximity to human landscape modifications, anthropogenic nest material use is correlated with synanthropic (artificial) nesting locations, breeding environment and the number of different nest materials the species has been recorded to use. We also demonstrate that body mass, range size, conservation status and brain size do not explain variation in the recorded use of anthropogenic nest materials. These results indicate that anthropogenic materials are more likely to be included in nests when they are more readily available, as well as potentially by species that are more flexible in their nest material choice

Nest traits for the world's birds

Funding: H2020 European Research Council, Grant/Award Number: 788203; John Templeton Foundation, Grant/Award Number: 60501.Motivation: A well-constructed nest is a key element of successful reproduction in most species of birds, and nest morphology varies widely across the class. Macroecological and macroevolutionary studies tend to group nest design into a small number of discrete categories, often based on taxonomic inference. In reality, however, many species display considerable intraspecific variation in their nest-building behaviour, and broad-level categories may include several functionally distinct nest types. To address this imprecision in the literature and facilitate future studies of broad-scale variation in avian parental care, we here introduce a detailed, global comparative database of nest building in birds, together with preliminary correlations between these traits and species-level environmental variables. Main types of variables contained: We present species-level data for nest structure, location, height, material composition, sex of builder, building time and nest dimensions. Spatial location and grain: Global. Maps are presented at the 10 × 10 level. Time period and grain: Included species are generally extant, although we present some data for recently extinct taxa. The data were collected in 2017–2021 and was drawn from secondary sources published in 1992–2021. Major taxa and level of measurement: Partial or complete trait data is presented for 8601 species of birds, representing 36 of 36 orders and 239 of 243 families. Software format: Data have been uploaded as Supplementary Material in .csv format and are separated by species and source for all traits (Dataset S1, and Metadata) as well as summarized at the species level for the major structure and location variables (Dataset S2, and Metadata).Publisher PDFPeer reviewe

Nest traits for the world's birds

We thank Mike Hansell, Mike Benton and members of the Healy and Lala labs, especially Sophie Edwards and Helen Spence-Jones, for comments on project design. This work was funded by the John Templeton Foundation (#60501 to KNL) and the European Research Council (788203 ‘Innovation’).Peer reviewe

The refinement paradox and cumulative cultural evolution : complex products of collective improvement favor conformist outcomes, blind copying, and hyper-credulity

Funding: Research supported in part by an European Research Council Advanced grant to KNL (EVOCULTURE, ref. 232823).Social learning is common in nature, yet cumulative culture (where knowledge and technology increase in complexity and diversity over time) appears restricted to humans. To understand why, we organized a computer tournament in which programmed entries specified when to learn new knowledge and when to refine (i.e. improve) existing knowledge. The tournament revealed a ‘refinement paradox’: refined behavior afforded higher payoffs as individuals converged on a small number of successful behavioral variants, but refining did not generally pay. Paradoxically, entries that refined only in certain conditions did best during behavioral improvement, while simple copying entries thrived when refinement levels were high. Cumulative cultural evolution may be rare in part because sophisticated strategies for improving knowledge and technology are initially advantageous, yet complex culture, once achieved, favors conformity, blind imitation and hyper-credulity.Peer reviewe

Culture and evolvability:a brief archaeological perspective

Evolvability refers to the capacity, ability, or potential of an organism to generate heritable variation. Under this view, much extragenetic inheritance is regarded not as noise, fine-tuning, or a luxury add-on to genetic inheritance but as an essential tool for short-term adaptation. With respect to humans, the cultural contribution to evolvability is key to understanding evolution. In many instances, cultural inheritance directs genetic inheritance, not the other way around. Culture, being relatively free from the genetic leash, can produce change that genetic inheritance cannot. Soft inheritance—the view that heredity can be changed by an organism’s experiences—has been disdained for over a century, but in light of the recent outpouring of data demonstrating extragenetic inheritance, defining evolution only in terms of genetic change ignores half the adaptive process, discarding much of what is interesting and relevant. Archaeologists can play a key role in evolvability research, given their contributions to topics such as niche construction, modularity, mosaic evolution, and developmental bias

Culture and evolvability:a brief archaeological perspective

Evolvability refers to the capacity, ability, or potential of an organism to generate heritable variation. Under this view, much extragenetic inheritance is regarded not as noise, fine-tuning, or a luxury add-on to genetic inheritance but as an essential tool for short-term adaptation. With respect to humans, the cultural contribution to evolvability is key to understanding evolution. In many instances, cultural inheritance directs genetic inheritance, not the other way around. Culture, being relatively free from the genetic leash, can produce change that genetic inheritance cannot. Soft inheritance—the view that heredity can be changed by an organism’s experiences—has been disdained for over a century, but in light of the recent outpouring of data demonstrating extragenetic inheritance, defining evolution only in terms of genetic change ignores half the adaptive process, discarding much of what is interesting and relevant. Archaeologists can play a key role in evolvability research, given their contributions to topics such as niche construction, modularity, mosaic evolution, and developmental bias

Dialectics That Sweep Away ‘COWDUNG’

Developmental geneticist Conrad Waddington and evolutionary biologist Richard Lewontin, two of the pioneers of niche construction theory, were explicit in regarding organisms as co-directing their own evolution. In The Ethical Animal (1960), Waddington anticipated features of contemporary cultural evolution theory, including the evolutionary significance of cultural norms. Lewontin was suspicious of evolutionary accounts of human behaviour, which he viewed as governed by political forces and power relations, and in The Dialectical Biologist (1985) stressed how scientific enquiry could be biased by politics. Here the authors suggest that Waddington’s emphasis on ethical considerations, and Lewontin’s admonitions concerning sociopolitical interpretation of biological research, remain relevant to the field of cultural evolution, and they review some related scientific controversies. The authors argue that human cultural activities not only construct evolutionary and cultural niches, but also scientific niches. This reasoning applies to both contemporary debates within the evolutionary human sciences and wider evolutionary theory, including niche construction theory itself

Humans flexibly integrate social information despite interindividual differences in reward

There has been much progress in understanding human social learning, including recent studies integrating social information into the reinforcement learning framework. Yet previous studies often assume identical payoffs between observer and demonstrator, overlooking the diversity of social information in real-world interactions. We address this gap by introducing a socially correlated bandit task that accommodates payoff differences among participants, allowing for the study of social learning under more realistic conditions. Our Social Generalization (SG) model, tested through evolutionary simulations and two online experiments, outperforms existing models by incorporating social information into the generalization process, but treating it as noisier than individual observations. Our findings suggest that human social learning is more flexible than previously believed, with the SG model indicating a potential resource-rational trade-off where social learning partially replaces individual exploration. This research highlights the flexibility of humans' social learning, allowing us to integrate social information from others with different preferences, skills, or goals

Social learning functions as an exploration tool in correlated environments

Humans can learn from observing diverse others, even when they know little about their exact preferences, skills, or goals. Yet, while our remarkable social learning abilities have been a popular research topic, prior work has generally been limited to tasks in which observer and demonstrator share the same value function. To address this discrepancy, we use the socially correlated bandit task, where participants explore positively correlated, rather than identical, environments in groups. We extend existing work using this paradigm by comparing behaviour across individual and social rounds within participants. We replicate findings that humans are able to use correlated social information effectively, with behaviour being best described by a model noisily integrates social information. In comparing individual and social search behaviour, we find that social learning partially replaces directed exploration. In conclusion, we find that humans use social information flexibly, employing it as an exploration tool, despite our differences