Tomas Redondo

Tomas Redondo
Spanish National Research Council | CSIC · Department of Ethology and Biodiversity Conservation

Ph. D.

About

52
Publications
13,974
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1,483
Citations
Citations since 2017
7 Research Items
293 Citations
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Introduction
I am interested in how behaviour and communication evolves within animal social groups (particularly bird families) when there are conflicting evolutionary interests among the parties (e.g. parents and offspring or nestmates, including brood parasites and their hosts). In particular, I have studied the evolution of begging signals in nestling passerines and how this communicative system can be exploited by parasitic cuckoos. I have further explored how cooperation and conflict are expressed in
Additional affiliations
August 1992 - present
Spanish National Research Council
August 1992 - present
Estación Biológica de Doñana
Position
  • Researcher
January 1992 - August 1992
University of Cambridge

Publications

Publications (52)
Data
Citation: Redondo, T., Romero, J. M., Díaz-Delgado, R. & Nagy, J. (2019) Broodmate aggression and life history variation in accipitrid birds of prey. Ecology and Evolution 9(16): 9185-9206 // List: Appendix S1. Testing potential biases due to heterogeneity in sampling effort. Appendix S2. Design of evolutionary causal layouts used in Path Analysi...
Article
Full-text available
Aggressive sibling competition for parental food resources is relatively infrequent in animals but highly prevalent and extreme among certain bird families, particularly accipitrid raptors (Accipitriformes). Intense broodmate aggression within this group is associated with a suite of traits including large adult size, small brood, low provisioning...
Article
Full-text available
Telomere length is a marker of cellular senescence that relates to different components of individual fitness. Oxidative stress is often claimed as a main proximate factor contributing to telomere attrition, although the importance of this factor in vivo has recently been challenged. Early development represents an ideal scenario to address this hy...
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Full-text available
Hematological profiles are routinely used to assess the health status of animals. Several methods have been developed for blood cell counting, but they are typically expensive and/or time-consuming. Here, we present a free image-processing software, Mizutama, developed for counting cells in photographs of blood smears. Mizutama uses the thresholdin...
Article
Altricial nestlings in structured families show a diverse array of behavioural mechanisms to compete for food, ranging from signalling scrambles to aggressive interference. Rates of filial infanticide are moderately high in white storks. It has been hypothesized that this unusual behaviour is an adaptive parental response to the absence of efficien...
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Full-text available
Many theoretical models on the evolution of nestling begging assume this behavior is costly, so that only nestlings in real need of food would profit from giving intensive signals to parents. However, evidence accumulated for the last 2 decades is either contradictory (growth costs) or scant (immunological cost). Here, we experimentally test the ex...
Chapter
La comunicación animal ha evolucionado como un proceso coadaptado entre receptores y emisores. Con la comunicación, los receptores mejoran sus decisiones respecto al medio en base a las señales producidas por los emisores. A su vez, los emisores se benefician de la influencia que ejercen sobre los receptores. Las señales evolucionan a partir de ind...
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Full-text available
Theoretical models aimed at explaining the evolution of honest, informative begging signals employed by nestling birds to solicit food from their parents, require that dishonest signalers incur a net viability cost in order to prevent runaway escalation of signal intensity over evolutionary time. Previous attempts to determine such a cost empirical...
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Full-text available
Theoretical models predict that a cost is necessary to guarantee honesty in begging displays given by offspring to solicit food from their parents. There is evidence for begging costs in the form of a reduced growth rate and immunocompetence. Moreover, begging implies vigorous physical activity and attentiveness, which should increase metabolism an...
Data
Model showing the effect of treatment on protein concentration. (PDF)
Data
Full-text available
Variation in mass gained by magpie nestlings between day 1 and day 3 of the experiment. (PDF)
Data
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Model showing the effect of treatment on the concentration of active enzyme superoxide dismutase (SOD). (PDF)
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Model showing the effect of treatment on the concentration of active enzyme glutathione peroxidase (GPX). (PDF)
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Measurement of enzymatic activity. (PDF)
Data
Full-text available
Model showing the effect of treatment on the concentration of active enzyme gluthatione reductase (GR). (PDF)
Article
Theoretical models suggest that begging should be costly in order to be evolutionarily stable. However, evidence for such a cost is contradictory (e.g. for growth costs) or scant (e.g. for immunological costs). Here, we experimentally test the existence of both costs in southern shrike (Lanius meridionalis) nestlings. Nestlings were paired by nest...
Article
Like most corvids, adult magpies (Pica pica) have harsh vocal repertoires characterized by a wide distribution of energy over the frequency scale. Shortly after hatching, begging calls of magpie nestlings have a tonal quality but become increasingly noisier as they develop. The appearance of harsh structures in the calls is closely related to a pro...
Article
Great Spotted Cuckoo nestlings were shown, after some days in the nest, to have begging calls that differed depending on whether they were being reared by Magpies or Carrion Crows. They also produced calls of a pitch and repetition rate that implied a high level of hunger.
Article
Full-text available
Differentiation of begging calls during development in three species of Corvids. Sonagrams of begging calls of Corvus corone, Corvus monedula and Pica pica were compared along three nestling developmental stages using factor discriminant analysis. Results showed an early intergenerie differentiation followed by the latter splitting of the two Corvu...
Article
Full-text available
The offspring of birds and mammals use a combination of movements and vocalizations, known as begging, to solicit food from their parents. A widespread interpretation of begging is that it constitutes an honest signal of offspring need. But we know that in the house sparrow (Passer domesticus) the intensity of begging calls reflects the past experi...
Chapter
Full-text available
Brood parasites may be favoured over host nestlings due to variation in the honesty of their begging signals. Begging behaviour of great spotted cuckoo nestlings and their host magpie nestlings was recorded when controlling food need. Cuckoo begging effort was dishonest as an indicator of nutritional need, whilst magpie begging was not. Cuckoos beg...
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We investigated whether an increase in begging levels delays growth of chicks. In experiment 1, we hand-reared nine pairs of ring dove squabs, divided into a control and a begging group. All squabs received similar amounts of food, but those in the begging group had to beg for a prolonged period in order to be fed, while squabs in the control group...
Article
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Article
White stork chicks were observed to abandon their natal nests prior to independence and be adopted by neighboring foster parents in approximately 40% of broods at 3 breeding colonies. Nest switching coincided with a decrease in feeding rates by parents and an increase in aggression by siblings triggered by the flight exercises of nestmates, and aff...
Article
White stork, Ciconia ciconia, chicks were observed to abandon their natal nests prior to independence and to be adopted by neighbouring foster parents in approximately 40% of broods at three breeding colonies. Nest switching coincided with a decrease in feeding rates by parents and an increase in aggression by siblings triggered by the flight exerc...
Book
Full-text available
Este es un libro (primero publicado por autores de lengua española) que trata sobre las estrategias que los seres vivos emplean para maximizar su eficacia biológica, abordadas desde los cuatro enfoques clásicos que constituyen la esencia de la Etología: las causas inmediatas o mecanismos, la ontogenia, la filogenia y la función adaptativa
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BROOD parasites and their hosts are thought to engage in a revolutionary arms race in which parasitism selects for adaptive defences by the host (such as egg rejection), which in turn select for counter-adaptations by the parasite (such as egg mimicry)1,2. Soler and Mø11er have tested whether the duration of coevolution (measured by the duration of...
Article
Begging activity in broods of Magpies Pica pica was measured as the average total number of begging nestlings and the number of nestlings giving begging calls between 5 and 9 days since the first nestling hatched. There was considerable between-brood variation in begging activity relative to day-to-day variation within broods. Predation between 7 a...
Article
The relationship between begging behaviour, chick nutritional state, and parental distribution of food within broods was studied in 4- and 5-chick magpie Pica pica broods under natural conditions. Three components of the begging display (duration, latency, and posture) were highly correlated with each other and also with the emission and duration o...
Article
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White Storks Ciconia ciconia parents were observed to kill their smaller chick in 9 out of 63 nests observed during a three-year study. Infanticidal parents were caring for larger broods and laid larger clutches than non-infanticidal birds. Males killed the chick in 8 out of 9 cases. Victims were born from the last-hatched egg in 4- and 5-egg clutc...
Article
White Storks Ciconia ciconia paired for ca. 30 days before laying a clutch. During this period, mates copulated frequently (160 copulations/pair; 0.4 copulations/daylight h), but copulation rate was drastically reduced a week before laying of the eggs. Both fewer copulation attempts by males and lower female receptivity accounted for this reduction...
Article
In species showing sexual dimorphism, parents may obtain different fitness returns per unit of parental expenditure from sons and daughters. Parents are then expected to invest extra resources in offspring of the most profitable sex. Parent-offspring conflict theory is used to investigate whether sex biases in parental expenditure should be accompa...
Article
Full-text available
The vocal repertoire of magpie (Pica pica) chicks consists of six calls: Begging Trill (BT), Soft Whistle (SW), Begging Scream (BS), Alarm Call (AC), Distress Call (DC) and Brief Contact Note (BCN). Both BT and SW have a tonal structure and their occurrence is restricted to the nestling period. At fledging, there is a gradual change from BT into BS...
Article
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The mating behaviour of red deer stags, Cervus elaphus, has been extensively described as harem defence. However, it appears that territoriality may be chosen as a mating strategy when certain conditions are met. In a study area in southwestern Spain, early on in the rut, about 58% of adult males established territories in preferred areas, defended...
Article
A model is proposed that, starting from a general theoretical standpoint about optimal parental care, integrates previous models and generates new predictions concerning variables not previously included, namely predatory risk for both parents and offspring and age-dependent defensive tactics of nestlings. Optimal levels of parental defence are the...
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Full-text available
Magpie (Pica pica) brood defense against a human at the nest was studied in a Mediterranean population with low renesting potential. Variations in two defense measures recorded during 106 trials at 41 different nests were positively correlated with brood age. Ineremental effects due to the number of successive visits to nests by us, brood size, and...
Article
Full-text available
All nests were found in holm oaks Quercus rotundifolia. Differences between colonies were observed regarding nest-tree size but not between variables characterizing the position of the nest. Nest height above ground did not correlate with tree size, while nest distance to bole did. Birds possibly maximized nest-bole distance in order to prevent pre...
Article
Nestling begging calls of altricial species of birds have design features (wide frequency range, abrupt onsets and modulation in amplitude and frequency) that make them easily located by birds and mammals, and so may attract predators to the nest. To be maintained by natural selection, such calls must also be beneficial. It is argued here that sibl...
Article
The variability in duration and form or red deer () alarm postures was studied. 18 variables of form were measured from photographic sequences and stereotypy calculated by means of Informational redundancy (IR). Comparisons between stereotypy estimates obtained by IR and those provided by the widely used coefficient of variation proved to match eac...

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Aggressive competition for food resources amog siblings is relatively infrequent in animals in general, but also observable in certain bird families. The intensity of broodmate aggression highly varies within and among groups and is associated with several traits including body and clutch size, provisioning rate etc. Which of these components are the most influential factors? How do environmental conditions affect the level of aggression?