Renata Durães

Annual Patterns of Molt and Reproductive Activity of Passerines in South-Central Brazil

Abstract We analyzed the occurrence of molt and brood patches in resident passerines from four localities in south-central Brazil. The annual patterns of molt and reproductive activity were very similar among the sites. Brood patches first appeared in August, but were most common between October and January, with a peak in November, early in the rainy season. Molt started in October but was most widespread from the middle to the end of the rainy season, between December and April with a peak in February. Timing of the appearance of brood patches was not related to trophic guild (insectivores, frugivores, omnivores). Molt of flight feathers started at the end of the reproductive period, which varied slightly among trophic guilds. Molt and brood patch overlap occurred in little more than 4% of individual birds, or in less than 2% considering just those molting flight feathers. This overlap occurred mostly between November and February. Regional environmental factors, instead of local factors, seem to be responsible for the annual breeding and molt patterns of the considered species. Padrões Anuais de Muda e Atividade Reprodutiva de Passeriformes na Região Centro-Sul do Brasil Resumo. Este estudo analisa a ocorrência de muda de penas e reprodução em Passeriformes residentes em quatro localidades na região centro-sul do Brasil. A atividade reprodutiva foi inferida a partir da presença de placas de incubação ativas. Os padrões anuais de muda e reprodução apresentaram-se bastante similares entre as regiões estudadas. Placas de incubação começaram a ser detectadas em agosto, sendo mais comuns entre outubro e janeiro, com um pico em novembro, no início da estação chuvosa. O principal período de mudas começou em outubro, sendo mais intensas nos dois terços finais da estação chuvosa, entre dezembro e abril, com um pico em fevereiro. Os padrões de ocorrência de reprodução e mudas apresentaram pequenas diferenças entre diferentes guildas alimentares, e, de modo geral, o início do período de mudas esteve relacionado ao fim do período reprodutivo. Sobreposição entre mudas e placas de incubação foi detectada em pouco mais de 4% do total de indivíduos analisados, ou em menos de 2%, quando apenas indivíduos mudando penas de vôo foram considerados. Esta sobreposição ocorreu principalmente entre novembro e fevereiro. Os padrões ambientais regionais, mais que os locais, parecem influenciar os ciclos anuais das espécies analisadas.

Destination-based seed dispersal homogenizes genetic structure of a tropical palm.

As the dominant seed dispersal agents in many ecosystems, frugivorous animals profoundly impact gene movement and fine‐scale genetic structure of plants. Most frugivores engage in some form of destination‐based dispersal, in that they move seeds towards specific destinations, resulting in clumped distributions of seeds away from the source tree. Molecular analyses of dispersed seeds and seedlings suggest that destination‐based dispersal may often yield clusters of maternal genotypes and lead to pronounced local genetic structure. The long‐wattled umbrellabird Cephalopterus penduliger is a frugivorous bird whose lek mating system creates a species‐specific pattern of seed dispersal that can potentially be distinguished from background dispersal processes. We used this system to test how destination‐based dispersal by umbrellabirds into the lek affects gene movement and genetic structure of one of their preferred food sources Oenocarpus bataua, a canopy palm tree. Relative to background dispersal processes, umbrellabird mating behaviour yielded more diverse seed pools in leks that included on average five times more seed sources and a higher incidence of long‐distance dispersal events. This resulted in markedly lower fine‐scale spatial genetic structure among established seedlings in leks than background areas. These species‐specific impacts of destination‐based dispersal illustrate how detailed knowledge of disperser behaviour can elucidate the mechanistic link driving observed patterns of seed movement and genetic structure.

Female mate choice across spatial scales: influence of lek and male attributes on mating success of blue-crowned manakins

Lekking males compete for females within and among leks, yet female choice is expected to work differently at each of these spatial scales. We used paternity analyses to examine how lek versus male attributes influence mate choice in the blue-crowned manakin Lepidothrix coronata. We tested the hypotheses that females prefer (i) to mate at larger leks where a larger number of potential mates can be assessed, (ii) to mate with unrelated or highly heterozygous males expected to produce high-quality offspring, (iii) to mate with males that display at higher rates, and that (iv) display honestly reflects male genetic quality. Our results show that (i) males at larger leks are not more likely to sire young, although females nesting close to small leks travel further to reach larger leks, (ii) siring males are not less related to females or more heterozygous than expected, (iii) within a lek, high-display males are more likely to sire young, and (iv) both male heterozygosity and display rate increased with lek size, and as a result display does not reliably reflect male genetic quality across leks. We suggest that female mate choice in this species is probably driven by a Fisherian process rather than adaptive genetic benefits.

ENVIRONMENTAL AND SPATIAL SEGREGATION OF LEKS AMONG SIX CO-OCCURRING SPECIES OF MANAKINS (PIPRIDAE) IN EASTERN ECUADOR

Abstract Environmental correlates and geographic spacing of leks were compared for six species of manakins (Pipridae) on two 100-ha study plots in eastern Ecuador. The “hotspot” hypothesis of lek evolution suggests that males should aggregate where females are most likely to be encountered. For ecologically similar species that co-occur at a site, leks are predicted to be clustered in space and, thus, to overlap in macroscale environmental characteristics. The geographic spacing and environmental characteristics of lek sites we observed were inconsistent with the hotspot hypothesis for lek evolution. In general, little geographic overlap occurred among leks, and geographic spacing of leks among heterospecifics more closely fit a regular than a clumped pattern. Further, environmental conditions of leks varied among species with respect to elevation and topography. Leks of some species were more likely to occur on hilltops or ridge tops (e.g., Machaeropterus regulus, Pipra erythrocephala), whereas others appeared to prefer highly dissected drainages (e.g., P. pipra), relatively flat terrain near streams (e.g., Chiroxiphia pareola), or seasonally inundated forests (e.g., P. filicauda). Using randomly placed leks, we found evidence that certain lek environments may be limited, which is consistent with observed levels of population abundances on the two plots. Such environmental limits may constrain lek placement and size. Further study is needed to determine the reproductive implications of placing leks in apparently suboptimal environments, though such compromises may reflect males making the best of a bad situation. Segregación Ambiental y Espacial de las Asambleas de Cortejo Entre Seis Especies Simpátricas de Saltarines (Pipridae) en el Oriente de Ecuador

Lek Structure and Male Display Repertoire of Blue-Crowned Manakins in Eastern Ecuador

Abstract. Among lek-breeding manakins (Pipridae), courtship repertoires are extremely diverse and have played a central role in establishing phylogenetic relationships within the family. Behaviorally, Lepidothrix is among the least known genera in the family, with brief accounts published for only two of the eight species. Here, I describe the lek structure, territory characteristics, vocalizations and behavioral display elements of the Blue-crowned Manakin (Lepidothrix coronata coronata) in eastern Ecuador. From 2003 to 2006, I located all leks in two 100-ha study plots (average of 13.5 leks 100 ha-1) and recorded behavior at individual territories in ten leks. Males displayed solitarily or at exploded leks with up to seven individual territories of ∼0.1 ha; within a lek, territory centers were separated by about 90 m. Males in definitive and predefinitive plumage (2 years and older) held stable territories, whereas first-year, female-plumaged males did not hold stable territories but sometimes associated loosely with territorial males. I noted 4 vocalizations and 11 male display behaviors during solitary and group displays involving other males and females, revealing a repertoire considerably more diverse than previously documented.

An evaluation of the use of tartar emetic in the study of bird diets in the Atlantic Forest of southeastern Brazil

Abstract Tartar emetic is frequently used to force regurgitation in birds, allowing the study of diet while minimizing mortality. However, the responsiveness to the emetic in terms of regurgitation and mortality rates has been shown to be highly species-specific. A total of 369 individuals (44 species) present in an area of Brazilian Atlantic Forest received the tartar emetic during 410 treatment events. These birds were mainly insectivores, frugivores, and omnivores. Regurgitation occurred in 70% of the treatments, with an overall pre-release mortality of 10%. Average latency time was 20 min, and it was not correlated with average species body mass. Incidence of regurgitation was lower and mortality was higher in the first hours of the day. Incidence of regurgitation varied with feeding guild, taxonomic family, and body mass classes in univariate tests, but only with guild after the effects of family and body mass had been controlled for. Incidence of mortality was affected by family. Responsiveness did not vary between males and females. Mortality occurred more frequently among individuals that failed to regurgitate than among individuals that did regurgitate (85% vs. 15% of mortality events). Recapture rates were lower among treated individuals than among untreated individuals (10 vs. 13%), and lower among treated individuals that failed to regurgitate than among those that did regurgitate (8 vs. 11%), but these differences were not statistically significant. Treated and untreated birds presented statistically similar displacement rates between transects (32 vs. 42%). Our recommendation is that the tartar emetic should be used with caution, and alternative methods should be favored for those species presenting unsatisfactory responses to the tartar emetic. We also recommend that the use of this substance should be avoided in the first hours of the day, when the birds had little time to forage.

OBTAINING OFFSPRING GENETIC MATERIAL: A NEW METHOD FOR SPECIES WITH HIGH NEST PREDATION RATES

Abstract ABSTRACT Over the past decade, the field of moleculargenetics has revolutionized our understanding ofavian mating systems, by demonstrating that socialbonds might not accurately reflect parentagebecause of unknown levels of cryptic mating(e.g., extra-pair copulations). Use ofmolecular genetics tools for paternity analysisrequires genetic material from putative parents andnestlings. Unfortunately, high nest predation ratesoften preclude detailed genetic studies of tropicaltaxa. Here, we describe a nondestructive methodthat increases the efficiency of obtaining geneticmaterial from offspring for a group of tropicalpasserines (Pipridae). The method entailsreplacing eggs with plaster replicas, incubatingeggs artificially, and returning hatchlings totheir original nests for further development. Thismethod greatly improved our ability to sampleoffspring, as we collected genetic material from100% of manipulated nests, compared to52% of unmanipulated nests.

Amphibian Diversity and Species Composition in Relation to Habitat Type and Alteration in the Mache–Chindul Reserve, Northwest Ecuador

Abstract:  Amphibians are facing extinctions worldwide as a result of numerous factors. Habitat alteration has long been implicated in the loss of biodiversity; however, we still do not know how different animal assemblages respond to habitat alteration. To investigate the impacts of anthropogenic habitat alteration on diversity, we studied amphibian assemblages across different habitats in the Chocó rainforest of northwest Ecuador. Amphibian diversity was estimated using intensive surveys along transects in primary and altered (historically logged) forest and riparian habitats, as well as along roads with varying levels of ongoing human activity. Our results suggest an interaction between habitat type and alteration on the diversity and composition of amphibian assemblages. Amphibian assemblages along rivers were the richest as well as the least impacted by habitat alteration. In addition, riparian zones harbored amphibian assemblages distinct from other habitat types, including rare and endangered species. Diversity and species richness were lower in secondary than in primary forest, suggesting that amphibian assemblages in interior forest habitat may be more vulnerable to alterations caused by logging. These findings suggest that amphibian assemblages in different habitat types (i.e., riparian vs. interior forest) may vary in vulnerability to habitat alteration. We discuss these findings in relation to land management plans that promote amphibian diversity in northwest Ecuador and recognize a good potential indicator species, Oophaga sylvatica, for identifying pristine habitat.

Impacts of Mating Behavior on Plant–Animal Seed Dispersal Mutualisms: A Case Study from a Neotropical Lek-Breeding Bird

Abstract In addition to affecting access to mates, traits under sexual selection may also impact interspecific ecological interactions such as predation, parasitism, and mutualistic interactions. This chapter addresses the ways in which sexual selection in general, and mating behavior in particular, may impact seed dispersal by lek-breeding birds. This phenomenon is likely to be of special importance in tropical rainforests, where the majority of plant species depend upon animal vectors for dispersal, and where the incidence of lekking behavior by frugivorous birds is high. We develop a series of predictions for how lekking might be expected to impact seed dispersal outcomes, tracing a chain of causality from lekking behavior to foraging ecology, to seed movement and deposition, to demographic and genetic characteristics of associated plants. Next, we summarize our efforts to test these predictions in the long-wattled umbrellabird (Cotingidae: Cephalopterus penduliger), a lek-breeding bird from a neotropical rainforest. Finally, we compare umbrellabirds with tropical and temperate counterparts that form leks and/or provide seed dispersal services. We conclude that mating behavior is likely to have an indirect but significant impact on plant species and communities via its effects on seed dispersal, and that this impact is likely to be disproportionately important in tropical rainforests.