A5076058654- Avian ecology and behavior
- Animal Behavior and Reproduction
- Bird parasitology and diseases
- Animal Ecology and Behavior Studies
- Wildlife Ecology and Conservation
- Plant and animal studies
- Animal Vocal Communication and Behavior
- Rangeland and Wildlife Management
- Marine animal studies overview
- Genetic diversity and population structure
- Climate variability and models
- Wildlife Conservation and Criminology Analyses
- Fire effects on ecosystems
- Species Distribution and Climate Change
- Genetic and Environmental Crop Studies
- Identification and Quantification in Food
- Ecology and Vegetation Dynamics Studies
- Neurobiology and Insect Physiology Research
- Animal Behavior and Welfare Studies
- Amphibian and Reptile Biology
- Physiological and biochemical adaptations
- Insect and Pesticide Research
- Genetic and phenotypic traits in livestock
- Fish Ecology and Management Studies
- Animal Nutrition and Physiology
University of Buenos Aires
2016-2025
Fundación Ciencias Exactas y Naturales
2015-2024
Consejo Nacional de Investigaciones Científicas y Técnicas
2015-2024
Institute of Astronomy and Space Physics
2014-2022
Google (United States)
2008-2012
Experimental Medicine and Biology Institute
1984-2000
University of Cambridge
1990-1993
To test the hypothesis that selection for spatial abilities which require birds to locate and return accurately host nests has produced an enlarged hippocampus in brood parasites, three species of cowbird were compared. In shiny cowbirds, females search without assistance male; screaming males inspect hosts' together; bay-winged neither sex searches because this is not a parasite. As predicted, two parasitic had relatively larger than non-parasitic species. There no differences relative size...
Egg mimicry by obligate avian brood parasites and host rejection of non-mimetic eggs are well-known textbook examples host–parasite coevolution. By contrast, reciprocal adaptations counteradaptations beyond the egg stage in their hosts have received less attention. The screaming cowbird ( Molothrus rufoaxillaris ) is a specialist parasite whose fledglings look identical to those its primary host, baywing Agelaioides badius ). Such resemblance has been proposed as an adaptation response...
Avian brood parasites, including cuckoos and cowbirds, have multiple negative effects on their hosts. We analysed the of Shiny Cowbird Molothrus bonariensis parasitism different components (e.g. egg losses, hatching success, chick survival nest abandonment) House Wren Troglodytes aedon reproductive success. also conducted an experiment to discriminate between two mechanisms that may reduce success in parasitized clutches: lower efficiency incubation due increase clutch volume disruption host...
The optimal acceptance threshold hypothesis provides a general predictive framework for testing behavioural responses to discrimination challenges. Decision-makers should respond stimulus when the perceived difference between that and comparison template surpasses an threshold. We tested how individual components of relevant recognition cue (experimental eggs) contributed chalk-browed mockingbirds, Mimus saturninus , frequent host parasitic shiny cowbird, Molothrus bonariensis . To do this,...
Starlings' preferences for constant versus variable food sources were studied in the laboratory. The alternative gave a fixed amount of after delay. offered either varying delay (treatment A) or B). In both treatments ratio over trial length (the sum intertrial interval plus and handling times) equaled average two ratios alternative. 30% higher smaller than ratio. free-choice trials (both options available each trial), subjects risk-averse indifferent treatment A riskprone B. no-choice (only...
Despite the costs to avian parents of rearing brood parasitic offspring, many species do not reject foreign eggs from their nests. We show that where multiple parasitism occurs, rejection itself can be costly, by increasing risk host egg loss during subsequent parasite attacks. Chalk-browed mockingbirds ( Mimus saturninus ) are heavily parasitized shiny cowbirds Molothrus bonariensis ), which also puncture in Mockingbirds struggle prevent puncturing and laying, but seldom remove cowbird once...
In a study of almost 16 000 nest records from seven swallow species across the entire Western Hemisphere, clutch sizes decline with relative laying date in each population, but slope this grows steeper increasing distance equator. Late‐laying birds at all latitudes lay clutches similar sizes, suggesting that latitudinal differences may be driven primarily by earlier‐laying birds. Focused comparisons site‐years North America qualitatively different food availability indicate supply...
Brood-parasitic cowbirds are hypothesized to search for and locate host nests within a relatively constant area, as this is presumed facilitate the monitoring of over time synchronization parasitism with laying. We tested hypothesis in Shiny Cowbirds (Molothrus bonariensis) Screaming (M. rufoaxillaris), two cowbird species that differ specificity and, apparently, social mating system, by radio-tracking females males 3–6 consecutive days determining individual daily morning ranges cumulative...
Abstract We studied the effect of sex and group size on proportion time a greater rhea, Rhea americana , allocates to vigilance feeding during breeding non‐breeding seasons. analysed 175 records focal animals that were alone or in groups 2 26 birds. In both seasons, males spent more less than females. Both sexes season. Sexual seasonal differences result different mechanisms. Males had shorter bouts females but there no sexual length bouts. On contrary, having longer season During season,...
Abstract We studied the effect of group size on proportion time that greater rheas, Rhea americana , allocated to vigilance and feeding during non‐breeding season. tested whether: (1) one bird allocates (individual vigilance) decreases with size, (2) at least is vigilant (collective increases size. analyzed video‐recordings birds were foraging alone or in groups from two 12 birds. The individual decreased spent increased In both cases main significant difference was between groups....
We collected observational data in three consecutive breeding seasons to study interactions between the botfly Philornis seguyi and Red-crested Cardinals (Paroaria coronata) a temperate zone near southern limit of distribution. analyzed: (1) seasonal trends prevalence parasitism, (2) influence parasitism on nestling growth rate survival, (3) association nest site vegetation at different scales (i.e., tree, surrounding landscape) probability parasitism. Prevalence was 28% higher later season....
Some brood parasites kill all their host's offspring shortly after hatching, whereas others are tolerant and reared in mixed host–parasite broods. This difference may arise because nestling face a "provisions trade-off," whereby the presence of host nestlings can increase or decrease parasite's food intake depending on whether young cause parents to supply more extra than they consume. We model this trade-off show that optimal nestmate number from perspective depends interaction 2 parameters...
Summary The Yellow Cardinal Gubernatrix cristata is a globally endangered passerine endemic to southern South America. Although the conservation status of this species alarming, there no information about factors that affect its reproductive success. We studied breeding biology population in Corrientes province north-east Argentina and report parameters, such as timing breeding, clutch size, hatching success chick survival analyse influencing nest survival. season lasted from October...
Greater Rheas(Rhea americana) have an unusual breeding system that combines harem-defense polygyny, communal egg laying, and exclusive male parental care. We studied survivorship of eggs nests in relation to clutch size timing estimated the reproductive success males females. The number a nest varied from 8 56, although most cases it was between 20 30. Nests with more than 30 35 had longer laying periods, lost during incubation, lower hatchability. As result, chicks hatched per increased up...
The Brown-and-yellow Marshbird (Pseudoleistes virescens) is a nonterritorial blackbird with helpers at the nest that inhabits temperate marshy areas and humid grasslands of Argentina, Uruguay, Brazil. We estimated nesting success marshbirds throughout breeding season (late September to mid-December) analyzed effects brood parasitism nest-site selection (i.e. substrate) on daily survival rates different stages cycle. Most nests were started in November, these had higher rate than those...