ORCID Profile
0000-0001-5010-2177
Current Organisation
University of Helsinki
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Publisher: PeerJ
Date: 21-03-2017
DOI: 10.7717/PEERJ.3062
Abstract: Video playback is becoming a common method for manipulating social stimuli in experiments. Parid tits are one of the most commonly studied groups of wild birds. However, it is not yet clear if tits respond to video playback or how their behavioural responses should be measured. Behaviours may also differ depending on what they observe demonstrators encountering. Here we present blue tits ( Cyanistes caeruleus ) videos of demonstrators discovering palatable or aversive prey (injected with bitter-tasting Bitrex) from coloured feeding cups. First we quantify variation in demonstrators’ responses to the prey items: aversive prey provoked high rates of beak wiping and head shaking. We then show that focal blue tits respond differently to the presence of a demonstrator on a video screen, depending on whether demonstrators discover palatable or aversive prey. Focal birds faced the video screen more during aversive prey presentations, and made more head turns. Regardless of prey type, focal birds also hopped more frequently during the presence of a demonstrator (compared to a control video of a different coloured feeding cup in an empty cage). Finally, we tested if demonstrators’ behaviour affected focal birds’ food preferences by giving in iduals a choice to forage from the same cup as a demonstrator, or from the cup in the control video. We found that only half of the in iduals made their choice in accordance to social information in the videos, i.e., their foraging choices were not different from random. In iduals that chose in accordance with a demonstrator, however, made their choice faster than in iduals that chose an alternative cup. Together, our results suggest that video playback can provide social cues to blue tits, but in iduals vary greatly in how they use this information in their foraging decisions.
Publisher: Proceedings of the National Academy of Sciences
Date: 04-08-2009
Abstract: Dietary ingested carotenoid biomolecules have been linked to both improved health and immunity in nestling birds. Here, we test whether maternally invested egg carotenoids can offset the cost of parasitism in developing nestling hihi ( Notiomystis cincta ) from the bloodsucking mite ( Ornithonyssus bursa ). Our results reveal clear negative effects of parasitism on nestlings, and that maternally derived carotenoids compensate this cost, resulting in growth parameters and ultimate mass achieved being similar to nonparasitized young. Our results offer an unique ex le of a direct positive relationship between enhanced maternal investment of carotenoids and an ability to cope with a specific and costly parasite in young birds. As O. bursa infestations reduce population viability in hihi, our findings also highlight the importance of key nutritional resources for endangered bird populations to better cope with common parasite infestations.
Publisher: Springer Science and Business Media LLC
Date: 25-06-2021
DOI: 10.1038/S41467-021-24154-0
Abstract: Social transmission of information is taxonomically widespread and could have profound effects on the ecological and evolutionary dynamics of animal communities. Demonstrating this in the wild, however, has been challenging. Here we show by field experiment that social transmission among predators can shape how selection acts on prey defences. Using artificial prey and a novel approach in statistical analyses of social networks, we find that blue tit ( Cyanistes caeruleus ) and great tit ( Parus major ) predators learn about prey defences by watching others. This shifts population preferences rapidly to match changes in prey profitability, and reduces predation pressure from naïve predators. Our results may help resolve how costly prey defences are maintained despite influxes of naïve juvenile predators, and suggest that accounting for social transmission is essential if we are to understand coevolutionary processes.
Publisher: Wiley
Date: 14-12-2021
DOI: 10.1111/OIK.08743
Abstract: Social information use is well documented across the animal kingdom, but how it influences ecological and evolutionary processes is only just beginning to be investigated. Here we evaluate how social transmission may influence species interactions and potentially change or create novel selection pressures by focusing on predator–prey interactions, one of the best studied ex les of species coevolution. There is extensive research into how prey can use social information to avoid predators, but little synthesis of how social transmission among predators can influence the outcome of different stages of predation. Here we review evidence that predators use social information during 1) encounter, 2) detection, 3) identification, 4) approach, 5) subjugation and 6) consumption. We use this predation sequence framework to evaluate the implications of social information use on current theoretical predictions about predator–prey dynamics, and find that social transmission has the potential to alter selection pressures for prey defences at each predation stage. This suggests that considering social interactions can help answer open questions about species coevolution, and also predict how populations and communities respond to rapid human‐induced changes in the environment.
Publisher: Wiley
Date: 19-02-2020
Publisher: Springer Science and Business Media LLC
Date: 11-06-2008
DOI: 10.1007/S00442-008-1073-3
Abstract: Carotenoids are integument pigments that often reflect foraging efficiency, disease resistance and body condition. In contrast to the widespread attention this relationship has received in adult birds, the condition dependence of nestling colouration remains an understudied component of animal communication. Here we assess the condition dependence of carotenoid pigmentation in nestling hihi (Notiomystis cincta, an endangered New Zealand bird) and examine the influence of carotenoid supplementation on nestling quality and parental visitation rates. Our results show that carotenoids provided to breeding adult hihi were transferred to their offspring and resulted in an intensified orange-yellow flange colour. After accounting for carotenoid supplementation the parameter that most consistently explained variation in nestling flange colour was nestling tarsus length at 23 days, indicating condition dependence of this trait. We did not, however, detect direct effects of carotenoid supplementation on nestling mass or immune response (or any other fitness parameter measured). Carotenoid supplementation did, however, result in an increased paternal provisioning rate.
Publisher: Oxford University Press (OUP)
Date: 03-12-2019
Abstract: Many prey species contain defensive chemicals that are described as tasting bitter. Bitter taste perception is, therefore, assumed to be important when predators are learning about prey defenses. However, it is not known how in iduals differ in their response to bitter taste, and how this influences their foraging decisions. We conducted taste perception assays in which wild-caught great tits (Parus major) were given water with increasing concentrations of bitter-tasting chloroquine diphosphate until they showed an aversive response to bitter taste. This response threshold was found to vary considerably among in iduals, ranging from chloroquine concentrations of 0.01 mmol/L to 8 mmol/L. We next investigated whether the response threshold influenced the consumption of defended prey during avoidance learning by presenting birds with novel palatable and defended prey in a random sequence until they refused to attack defended prey. We predicted that in iduals with taste response thresholds at lower concentrations would consume fewer defended prey before rejecting them, but found that the response threshold had no effect on the birds’ foraging choices. Instead, willingness to consume defended prey was influenced by the birds’ body condition. This effect was age- and sex-dependent, with adult males attacking more of the defended prey when their body condition was poor, whereas body condition did not have an effect on the foraging choices of juveniles and females. Together, our results suggest that even though taste perception might be important for recognizing prey toxicity, other factors, such as predators’ energetic state, drive the decisions to consume chemically defended prey.
Publisher: Oxford University Press (OUP)
Date: 2014
Publisher: Springer Science and Business Media LLC
Date: 03-07-2020
Publisher: Wiley
Date: 10-07-2019
Publisher: Wiley
Date: 11-12-2022
Abstract: Decades of research have shown that the coevolutionary arms race between avian brood parasites and their hosts can promote phenotypic ersification in hosts and brood parasites. However, relatively little is known about the role of brood parasitism in promoting phenotypic ersification of nestlings. We review field data collected over four decades in Australia, New Caledonia and New Zealand to assess potential for coevolutionary interactions between the shining bronze‐cuckoo ( Chalcites lucidus ) and its hosts, and how ersification at the nestling stage may be generating different subspecies. The shining bronze‐cuckoo is a specialist parasite of a few hosts in the family Acanthizidae. It has ersified into subspecies, of which the nestlings closely mimic the respective host nestlings in each region. Additionally, some cuckoo subspecies have polymorphic nestlings. The Acanthizidae hosts have similar breeding and nesting habits and only moderately effective frontline defences against parasitism at cuckoo egg laying or at the egg stages. However, some hosts have developed highly effective defences at the nestling stage by recognising and ejecting cuckoo nestlings from the nest. As with the cuckoo nestlings, some hosts have polymorphic nestlings. The coevolutionary interactions in each region suggest different evolutionary stages of the arms race in which either the parasite or the host is currently in the lead. The presence of moderately effective defences at the egg laying and egg stages might explain why some hosts do not have defences at the nestling stage. The south‐Pacific cuckoo – host systems are excellent models to explore the evolutionary mechanisms driving the ersification at the nestling stage in the coevolutionary arms race between avian brood parasites and their hosts.
Publisher: Oxford University Press (OUP)
Date: 03-06-2022
Abstract: Animals gather social information by observing the behavior of others, but how the intensity of observed cues influences decision-making is rarely investigated. This is crucial for understanding how social information influences ecological and evolutionary dynamics. For ex le, observing a predator’s distaste of unpalatable prey can reduce predation by naïve birds, and help explain the evolution and maintenance of aposematic warning signals. However, previous studies have only used demonstrators that responded vigorously, showing intense beak-wiping after tasting prey. Therefore, here we conducted an experiment with blue tits (Cyanistes caeruleus) informed by variation in predator responses. First, we found that the response to unpalatable food varies greatly, with only few in iduals performing intensive beak-wiping. We then tested how the intensity of beak-wiping influences observers’ foraging choices using video-playback of a conspecific tasting a novel conspicuous prey item. Observers were provided social information from 1) no distaste response, 2) a weak distaste response, or 3) a strong distaste response, and were then allowed to forage on evolutionarily novel (artificial) prey. Consistent with previous studies, we found that birds consumed fewer aposematic prey after seeing a strong distaste response, however, a weak response did not influence foraging choices. Our results suggest that while beak-wiping is a salient cue, its information content may vary with cue intensity. Furthermore, the number of potential demonstrators in the predator population might be lower than previously thought, although determining how this influences social transmission of avoidance in the wild will require uncovering the effects of intermediate cue salience.
Publisher: PeerJ
Date: 04-11-2019
DOI: 10.7717/PEERJ.7998
Abstract: Video playback provides a promising method to study social interactions, and the number of video playback experiments has been growing in recent years. Using videos has advantages over live in iduals as it increases the repeatability of demonstrations, and enables researchers to manipulate the features of the presented stimulus. How observers respond to video playback might, however, differ among species, and the efficacy of video playback should be validated by investigating if in iduals’ responses to videos are comparable to their responses to live demonstrators. Here, we use a novel foraging task to compare blue tits’ ( Cyanistes caeruleus ) responses to social information from a live conspecific vs video playback. Birds first received social information about the location of food, and were then presented with a three-choice foraging task where they could search for food from locations marked with different symbols (cross, square, plain white). Two control groups saw only a foraging tray with similar symbols but no information about the location of food. We predicted that socially educated birds would prefer the same location where a demonstrator had foraged, but we found no evidence that birds copied a demonstrator’s choice, regardless of how social information was presented. Social information, however, had an influence on blue tits’ foraging choices, as socially educated birds seemed to form a stronger preference for a square symbol (against two other options, cross and plain white) than the control birds. Our results suggest that blue tits respond to video playback of a conspecific similarly as to a live bird, but how they use this social information in their foraging decisions, remains unclear.
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Rose Thorogood.