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A review of the diet of the gray-hooded attila (Attila rufus)
Abstract
The knowledge on the diet of neotropical birds species is incipient, and even common and widespread species still lack this basic information. In the present study we reviewed the diet of the gray-hooded attila (Attila rufus), a species endemic to the Atlantic Forest biome. For this, three approaches were used: literature review, citizen science data and fieldwork. Data from fieldwork was obtained through the monitoring of prey items used to feed nestlings from two nests found in the 2023/24 breeding season in the municipality of Santo Amaro da Imperatriz, Santa Catarina state, southern Brazil. We found a total of 18 publications (papers and books) reporting some aspect of the species’ diet, citizen science data was composed by 121 media, and 49 nestling feeding events were observed during fieldwork. Our results indicate that vertebrates, especially anurans, and larger arthropods are the most important components of the bird diet. Fruits were also consumed but their importance in the diet is unclear due to absence of quantitative data. Therefore, the gray-hooded attila can be considered primarily a carnivore-insectivore bird and one of the most specialised Atlantic Forest passerines preying on vertebrates.
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The present study reports for the first time the predation of a tropical house gecko (Hemidactylus mabouia) by white-throated woodcreeper (Xiphocolaptes albicollis), a species of neotropical forest bird. Since reports on predation are few and scattered, we also present a brief review of the predatory birds of H. mabouia.
Systematic assessments of species extinction risk at regular intervals are necessary for informing conservation action1,2. Ongoing developments in taxonomy, threatening processes and research further underscore the need for reassessment3,4. Here we report the findings of the second Global Amphibian Assessment, evaluating 8,011 species for the International Union for Conservation of Nature Red List of Threatened Species. We find that amphibians are the most threatened vertebrate class (40.7% of species are globally threatened). The updated Red List Index shows that the status of amphibians is deteriorating globally, particularly for salamanders and in the Neotropics. Disease and habitat loss drove 91% of status deteriorations between 1980 and 2004. Ongoing and projected climate change effects are now of increasing concern, driving 39% of status deteriorations since 2004, followed by habitat loss (37%). Although signs of species recoveries incentivize immediate conservation action, scaled-up investment is urgently needed to reverse the current trends.
Birds are important bioindicators and have been frequently used to ascertain and monitor environmental changes. Therefore, even today in the twenty-first century, it is of great importance to study and accumulate basic information on birds’ natural history, including their diet. Here, we analyzed 180 stomach contents for 93 species of birds belonging to 34 families. These birds have been collected mostly in the Brazilian Cerrado savannas, with some few samples obtained in the Atlantic Forest. We found in the stomach contents analyzed mostly arthropods, especially the insect orders Coleoptera and Hymenoptera. Vegetable matter, especially fruits, grains, and unidentified seeds, was also prevalent, but it was often not possible to identify the botanical material, which was frequently ground up. This is one of the most comprehensive studies to date about the diet of Brazilian birds, covering a poorly sampled region in the state of Mato Grosso as well as understudied species.
This data paper describes a compilation of 73,075 quantitative diet data records for 759 primarily North American bird species, providing standardized information not just on the diet itself, but on the context for that diet information including the year, season, location, and habitat type of each study. The methods used for collecting and cleaning these data are described, and we present tools for summarizing and visualizing diet information by bird species or prey.
Birds often hold important positions in the food webs of ecosystems. As a result, interactions between birds and their prey have attracted attention not only in ecology, but also in fields like agriculture and conservation. Avian food resources are well researched in Japan, however there is no database critically reviewing molluscs as a food resource for birds. Here, we present a new database reviewing dietary information for all Japanese bird species. In addition to addressing general diet categories and specific food habits for each bird, we include detailed data on the molluscan prey observed for all species that consume them. The information within this database was collected through intense literary review to provide a complete look at bird species historically present around the country. We also include new information on snail species found in the upper digestive tract of harvested wild birds. This database is publicly available in the Zenodo repository. The information should aid research around the Japanese archipelago, especially projects involving birds or molluscs.
Securing the long-term resilience of the world’s most speciose avifauna, that of the Neotropics, requires spatially and temporally explicit data to inform decisions. We examine gaps in our knowledge of the region’s avifauna through the lens of the biodiversity shortfall concept: the gaps between realized knowledge and complete knowledge. This framework serves as a useful tool to take stock of the last 25 yr of Neotropical ornithological work since the untimely death of Ted Parker. Here, we highlight 7 key shortfalls: taxonomy, distribution, abundance, evolutionary patterns, abiotic tolerances, species traits, and biotic interactions. We then propose an eighth—and new—“Parkerian” shortfall that reflects a lack of basic natural history knowledge key to understanding how species might respond to environmental challenges. Bridging this shortfall will help reverse declines by informing reintroduction, recovery network, and habitat restoration efforts. We discuss the challenges imposed by each shortfall and how strategies such as citizen-science initiatives and technological advances can either remedy or mitigate the uncertainty they generate.
The bird fauna of the Brazilian Atlantic Forest is exceptionally diverse and threatened, with high levels of endemism. Available lists of the endemic birds of the Atlantic Forest were generated before recent taxonomic revisions lumped or split species and before the recent increase in species occurrence records. Our objective, therefore, was to compile a new list of the endemic birds of the Atlantic Forest, characterize these species in terms of conservation status and natural history traits, and map remaining vegetation and protected areas. We combined GIS analysis with a literature search to compile a list of endemic species and, based on the phylogeny and distribution of these species, characterized areas in terms of species richness, phylogenetic diversity, and endemism. We identified 223 species of birds endemic to the Atlantic Forest, including 12 species not included in previous lists. In addition, 14 species included in previous lists were not considered endemic, either because they occur outside the Atlantic Forest biome or because they are not considered valid species. The typical Atlantic Forest endemic bird is a small forest-dependent invertivore. Of the species on our list, 31% are considered threatened or extinct. Only ~ 34% of the spatial analysis units had > 10% forest cover, and protected area coverage was consistently low (< 1%). In addition, we found spatial incongruity among the different measures of biodiversity (species richness, relative phylogenetic diversity, restricted-range species, and irreplaceability). Each of these measures provides information concerning different aspects of biological diversity. However, regardless of which aspect(s) of biodiversity might be considered most important, preservation of the remaining areas of remnant vegetation and further expansion of protected areas are essential if we are to conserve the many endemic species of birds in the Atlantic Forest.
INTRODUÇÃO Gostaríamos inicialmente de propor um pequeno desafio ao leitor: escolha um trecho mais ou menos primitivo de Mata Atlântica no sudeste do Brasil, entre al-guns passos em seu interior, fique de pé e gire lentamente sobre seus calcanhares num círculo completo. Tente, então, re-conhecer num raio de dez metros, ou um pouco mais, uma parcela da profusão de plantas que você notará desde o solo, pas-sando pelos troncos de árvores, até o estra-to médio da floresta. Não fique desapon-tado, ou mesmo desestimulado, caso não consiga identificar praticamente nenhuma delas. Isto aconteceria, quase certamente, com muitos naturalistas, ornitólogos, en-tomólogos e até mesmo com grande parte dos botânicos. Não é um exagero afirmar que um cientista precisaria de várias vidas para estudar a história natural de apenas uma parte destas plantas, assim como as interações que elas estabelecem entre si e com animais de diversos tipos. Uma das mais famosas características de uma flo-resta tropical é a extrema diversidade de formas de vida. Não é incomum que um quilômetro quadrado de florestas na Amé-rica do Sul contenha várias centenas de es-pécies de plantas ou de aves, assim como incontáveis tipos de borboletas, besouros e outros insetos (Wilson 1997). O palco de nosso estudo é a complexa Mata Atlântica, um dos mais importantes e emblemáticos biomas deste continen-te. A despeito de encontrar-se atualmente bastante depauperada e fragmentada, em virtude do impiedoso processo de colo-nização empregado pelo homem, a Mata Atlântica ainda abriga mais de 8.000 es-pécies endêmicas de plantas vasculares, anfíbios, répteis, aves e mamíferos (Dean 1996, Myers et al. 2000, Parrini 2015). Ao lado da vasta Amazônia, as florestas costeiras do leste do Brasil respondem pela maior parte da magnífica e exuberante biodiver-sidade brasileira. Por outro lado, a extrema riqueza biológica de ecossistemas florestais, como a Mata Atlântica, costuma impor Figura 1. Mapa da Sede Teresópolis do Parnaso, com indicação da Estrada da Barragem, trilhas limítrofes e outros pontos de interesse mencionados neste trabalho. Meramente esquemático e ilustrativo.
The dataset provided here includes 8320 frugivory interactions (records of pairwise interactions between plant and frugivore species) reported for the Atlantic Forest. The dataset includes interactions between 331 vertebrate species (232 birds, 90 mammals, five fishes, one amphibian and three reptiles) and 788 plant species. We also present information on traits directly related to the frugivory process (endozoochory), such as the size of fruits and seeds and the body mass and gape size of frugivores. Data were extracted from 166 published and unpublished sources spanning from 1961 to 2016. While this is probably the most comprehensive dataset available for a tropical ecosystem, it is arguably taxonomically and geographically biased. The plant families better represented are Melastomataceae, Myrtaceae, Moraceae, Urticaceae and Solanaceae. Myrsine coriacea, Alchornea glandulosa, Cecropia pachystachya, and Trema micrantha are the plant species with the most animal dispersers (83, 76, 76 and 74 species, respectively). Among the animal taxa, the highest number of interactions is reported for birds (3883), followed by mammals (1315). The woolly spider monkey or muriqui, Brachyteles arachnoides, and rufous-bellied thrush, Turdus rufiventris, are the frugivores with the most diverse fruit diets (137 and 121 plants species, respectively). The most important general patterns that we note are that larger seeded plant species (>12 mm) are mainly eaten by terrestrial mammals (rodents, ungulates, primates and carnivores) and that birds are the main consumers of fruits with a high concentration of lipids. Our dataset is geographically biased, with most interactions recorded for the southeast Atlantic Forest. This article is protected by copyright. All rights reserved.
Pequeno é ainda o número de trabalhos que tratam do conteúdo gástrico das aves do Brasil. Existem muitas indicações espalhadas nos trabalhos clássicos sobre a avifauna, como, por exemplo, nos estudos do Príncipe de Wied, Burmeister e outros, resultados aproveitados em larga escala por A. Brehm no seu célebre livro u Tierleben". Nos últimos anos apareceram algumas publicações brasileiras sobre este assunto. Em 1941 veio a lúmen o trabalho de João Moojen, José Cândido de Carvalho e Hugo de Souza Lopes, sobre as aves dos arredores de Viçosa (MG), de Ilha Seca no Noroeste de São Paulo e de Salobra no Leste de Mato Grosso, apresentando os resultados de 784 exemplares de aves (189 espécies). Em 1949 foi publicado um trabalho póstumo de Adolpho Hempel, incluindo 61 espécies em 110 exemplares, além de informações sobre 53 perdizes {Rhynchotus) e 117 codornas (Nothura), provenientes do Estado de São Paulo e regiões limítrofes.
Souza, R.D.R. de, M.T. Moroti, J. Briet, and I.F. Machado. 2016. Vitreorana uranoscopa. Predation by Attila rufus. Herpetological Review 47(4) 651.
Dietary studies give vital insights into foraging behaviour, with implications for understanding changing environmental conditions and the anthropogenic impacts on natural resources. Traditional diet sampling methods may be invasive or subject to biases, so developing non‐invasive and unbiased methods applicable to a diversity of species is essential.
We used digital photography to investigate the diet fed to chicks of a prey‐carrying seabird and compared our approach (photo‐sampling) to a traditional method (regurgitations) for the greater crested tern Thalasseus bergii .
Over three breeding seasons, we identified >24 000 prey items of at least 48 different species, more than doubling the known diversity of prey taken by this population of terns. We present a method to estimate the length of the main prey species (anchovy Engraulis encrasicolus ) from photographs, with an accuracy <1 mm and precision ~ 0·5 mm. Compared to regurgitations at two colonies, photo‐sampling produced similar estimates of prey composition and size, at a faster species accumulation rate. The prey compositions collected by two researchers photo‐sampling concurrently were also similar.
Photo‐sampling offers a non‐invasive tool to accurately and efficiently investigate the diet composition and prey size of prey‐carrying birds. It reduces biases associated with observer‐based studies and is simple to use. This methodology provides a novel tool to aid conservation and management decision‐making in the light of the growing need to assess environmental and anthropogenic change in natural ecosystems.
Descriptions of avian diets currently lack consistent terminology and standardized methods. As a consequence, most available classifications, especially for tropical birds, are inconsistent and often misleading. We identified 23 food categories most commonly eaten by birds (e.g., seeds, fruits, and insects) and proposed standard names that accurately describe the diet type associated with each food category (e.g., granivore, frugivore, and insectivore). We also propose a classification scheme for avian diet types that takes into account the number of food categories consumed and the volumetric proportion (based on stomach content analysis) of each category eaten to indicate the diet type of a species, using a binomial terminology. Given that bird diets encompass a continuum between some extremes commonly treated as distinct categories, we adopted arbitrary breaking points to delimit distinct diet types. For example, species with different proportions of insects and fruits in their diets can be classified as insectivores (IN), insectivores secondarily frugivores (INFR), frugivores-insectivores (FR-IN), frugivore secondarily insectivores (FRIN), and frugivores (FR). Because many factors can influence avian diets, the diet types of species can also be classified based on age-related, sexual, seasonal, and/or geographic variation, e.g., young are insectivores and adults are frugivores, we believe that our classification scheme provides a standardized terminology that can contribute to a more consistent and effective exchange of information about avian diets.
Enigmatic amphibian declines were first reported in southern and southeastern Brazil in the late 1980s and included several species of stream-dwelling anurans (families Hylodidae and Cycloramphidae). At that time, we were unaware of the amphibian-killing fungus Batra-chochytrium dendrobatidis (Bd); therefore, pollution, habitat loss, fragmentation and unusual climatic events were hypothesized as primary causes of these declines. We now know that multiple lineages of Bd have infected amphibians of the Brazilian Atlantic forest for over a century, yet declines have not been associated specifically with Bd outbreaks. Because stream-dwelling anurans occupy an environmental hotspot ideal for disease transmission , we investigated temporal variation in population and infection dynamics of three stream-adapted species (Hylodes asper, H. phyllodes, and Cycloramphus boraceiensis) on the northern coast of São Paulo state, Brazil. We surveyed standardized transects along streams for four years, and show that fluctuations in the number of frogs correlate with specific climatic variables that also increase the likelihood of Bd infections. In addition, we found that Bd infection probability in C. boraceiensis, a nocturnal species, was significantly higher than in Hylodes spp., which are diurnal, suggesting that the nocturnal activity may either facilitate Bd zoospore transmission or increase susceptibility of hosts. Our findings indicate that, despite long-term persistence of Bd in Brazil, some hosts persist with seasonally variable infections, and thus future persistence in the face of climate change will depend on the relative effect of those changes on frog recruitment and pathogen proliferation.
Seabirds are upper trophic level predators, and are often highly sensitive to changes in the availability of their prey. Altered prey assemblages resulting from fluctuations in oceanographic conditions may be mirrored by shifts in seabird diet. Long-term studies of dietary change in seabirds therefore provide valuable insight into the nature of environmental shifts within the systems in which they forage. In recent decades, the Agulhas region in South Africa has undergone significant oceanographic change related to warming and intensification of the Agulhas current. Concurrent with this change, the population of Cape gannets Morus capensis at Bird Island, Algoa Bay, has grown rapidly, probably as a result of an increased availability of its dominant prey items, sardine Sardinops sagax and anchovy Engraulis encrasicolus. Using one of the longest and most complete time-series available on diet of a seabird (spanning 34 years), we tested for changes in composition and the abundance of dominant prey species of this population. These observed changes were also compared with acoustic survey estimates of their biomass, and annual catch data. Since 1979, the prey composition has remained similar, but the dietary contribution of sardine and anchovy, which fluctuated inversely to each other, increased over the study period. These shifts seem to be reflective of fluctuations in the stock size of sardine and anchovy. Conversely, a third species, saury Scomberesox saurus, dominant in the non-breeding diet of the 1980s, decreased significantly in dietary abundance over the following two decades. It is likely that dietary shifts of Cape gannets at Bird Island were related to climate-mediated oceanographic change. The implications of such changes are discussed.
Em florestas tropicais, ainda são incipientes os estudos que tratam da influência dos bambus na dinâmica da vegetação. Pela grande capacidade de se expandir rapidamente no ambiente seja por crescimento vegetativo ou por produção massiva de sementes, os bambus promovem alterações significativas na estrutura das comunidades vegetais. Desta forma, esse estudo teve como objetivo avaliar o ciclo de vida das plantas em ambientes com (B) e sem bambus (SB) em uma área de floresta Atlântica densamente ocupada pelo bambu nativo Guadua tagoara. Os objetivos específicos deste estudo foram separados em capítulos. Para o capítulo 1, conhecer a composição de aves associadas aos ambientes com e sem bambus, identificar as aves que compõem a guilda de dispersores de sementes de Euterpe edulis, Sloanea guianensis e Virola bicuhyba e avaliar o potencial de dispersão das aves registradas em censos. Para o capítulo 2, avaliar o padrão espacial dos estágios iniciais da regeneração da comunidade de plantas nos ambientes B e SB. Finalmente para o capítulo 3, quantificar as perdas de propágulos e as probabilidades de transição entre cada etapa demográfica das três espécies de plantas selecionadas, e identificar os gargalos demográficos do recrutamento que podem colapsar a regeneração natural das três espécies de plantas nos ambientes B e SB. Verificamos que nos ambientes B foi registrado maior número de espécies de aves do que em ambientes SB. A maioria das aves registradas em censos nos dois ambientes foi insetívora, seguida por espécies frugívoras. A efetividade da dispersão de Euterpe, Sloanea e Virola, esteve restrita a um pequeno grupo de dispersores efetivos. As aves que mais contribuíram para a dispersão de Virola ocorreram mais freqüentemente em B. Este padrão foi similar para Sloanea, enquanto Euterpe apresentou um padrão misto, com algumas espécies de aves contribuindo para a dispersão em B e outras espécies em SB. Concluímos que um número considerável de espécies de aves frugívoras pode favorecer bordas de manchas de bambu e seu interior e que estes ambientes constituem elementos importantes da vegetação por funcionarem como áreas de abrigo e alimentação para muitas espécies de aves. Considerando o padrão espacial, verificamos que a comunidade de plantas da área estudada está com o recrutamento limitado nos dois ambientes como resultado da combinação de fatores bióticos e abióticos. Os bambus influenciam o padrão da chuva de sementes no complexo mosaico florestal quanto ao número de recrutas e riqueza de espécies de sementes. Além disso, os hotspots de recrutamento aparecem como extremamente dinâmicos e relacionados à expansão e declínio das manchas de G. tagoara. Os bambus promovem a heterogeneidade da floresta, mas as características de rápida colonização de G. tagoara e seu comportamento invasivo podem ser mais um fator de limitação do crescimento das comunidades vegetais sendo importante seu manejo. Quando avaliamos o ciclo de vida das plantas em nível populacional, verificamos que os propágulos das três espécies, quando protegidos da atividade de vertebrados, apresentaram maior probabilidade de chegar às fases posteriores do recrutamento. Assim, concluímos que a susceptibilidade à predação foi o principal gargalo demográfico durante as fases iniciais do estabelecimento. Os efeitos da presença do bambu no estabelecimento inicial são espécie-específica, pois nossos resultados indicam que o estabelecimento inicial de Euterpe, Sloanea e Virola na floresta Atlântica pode ser extremamente desigual, com uma profunda influência da heterogeneidade criada pelas manchas de bambu.
We investigated if passerine birds act as important predators of small vertebrates within the Neotropics. We surveyed published studies on bird diets, and information on labels of museum specimens, compiling data on the contents of 5,221 stomachs. Eighteen samples (0.3%) presented evidence of predation on vertebrates. Our bibliographic survey also provided records of 203 passerine species preying upon vertebrates, mainly frogs and lizards. Our data suggest that vertebrate predation by passerines is relatively uncommon in the Neotropics and not characteristic of any family. On the other hand, although rare, the ability to prey on vertebrates seems to be widely distributed among Neotropical passerines, which may respond opportunistically to the stimulus of a potential food item.
New technologies are rapidly changing the way we collect, archive, analyze, and share scientific data. For example, over the next several years it is estimated that more than one billion autonomous sensors will be deployed over large spatial and temporal scales, and will gather vast quantities of data. Networks of human observers play a major role in gathering scientific data, and whether in astronomy, meteorology, or observations of nature, they continue to contribute significantly. In this paper we present an innovative use of the Internet and information technologies that better enhances the opportunity for citizens to contribute their observations to science and the conservation of bird populations. eBird is building a web-enabled community of bird watchers who collect, manage, and store their observations in a globally accessible unified database. Through its development as a tool that addresses the needs of the birding community, eBird sustains and grows participation. Birders, scientists, and conservationists are using eBird data worldwide to better understand avian biological patterns and the environmental and anthropogenic factors that influence them. Developing and shaping this network over time, eBird has created a near real-time avian data resource producing millions of observations per year.
This study presents quantitative information on the diet of 22 passerine bird species occurring in an area of Atlantic forest in Southeast Brazil, based on the analysis of 253 regurgitation samples obtained with tartar emetic. Sampling adequacy was verified by cumulative curves with randomized re- sampling, what allowed identifying 13 species for which diet diversity was adequately sampled during the study period. Ten samples were sufficient to adequately describe the diet diversity of most species. We used a quantitative index to describe diet composition that incorporates information on both abundance and occurrence of diet categories, and we propose the use of this index in bird diet studies as a more informa- tive alternative than the usually adopted indices of relative abundance. The most important diet categories overall were Coleoptera, Formicidae, non-ant Hymenoptera, adult and larval Lepidoptera, Araneae, insect eggs, Blattodea oothecae, Homoptera, fruits, and seeds. Guild affiliation and intraguild differences in the diet of the bird species are discussed. Accepted 30 November 2004.
RESUMO. Dieta de algumas aves da Mata Atlântica. Para muitas espécies de aves Neotropicais simplesmente inexistem dados relativos à sua dieta, uma informação fundamental para o estabelecimento de estratégias de conservação. Neste estudo são apresentados dados sobre a dieta de 88 espécies de aves da Mata Atlântica, sendo analisados 326 conteúdos estomacais obtidos através da regurgitação forçada por tártaro emético. Os insetos encontrados foram agrupados em ordens e os demais artrópodes em classes. As sementes foram classificadas em morfotipos, agrupadas em classes de tamanho e contadas. Os principais artrópodes ingeridos foram os Coleoptera e Formicidae. Já entre as sementes predominaram as compreendidas entre 0,1 e 1,5 mm. A publicação de novos e detalhados estudos sobre a dieta de aves Neotropicais é fortemente recomendada. PALAVRAS-CHAVE: aves, dieta, Mata Atlântica, neotrópicos, tártaro emético. ABSTRACT. The diet of many neotropical birds is unknown and these data are essential for the development of conservation strategies. Here we describe the diet of 88 Atlantic Forest bird species, from 326 individuals whose stomach contents were obtained by regurgitation by the use of tartar emetic. Stomach contents were examined in the laboratory under a stereomicroscope. Insects were grouped by Order and other arthropods by Class. Seeds were counted, measured, and identified to family level when possible. The main arthropods in the diet were Coleoptera and Hymenoptera (Formicidae). Seeds ingested were mostly small (< 1.5 mm). New diet studies for neotropical birds are strongly recommended.
Spatial and temporal distribution of anurans in a swamp of Reserva Biológica de Duas Bocas, Southeastern Brazil. This study aimed to investigate space and time partitioning related to reproductive activity of anuran species in a swamp of Reserva Biológica de Duas Bocas, State of Espírito Santo, Southeastern Brasil. We evaluate space use distribution through vertical distribution, obtained by the measurement of height in relation to water, and horizontal distribution, obtained by the recognition of regions and microhabitats used as calling sites at the swamp. To verify temporal distributions, the annual activity period and daily vocalization turn of each species were recorded. Nineteen species, distributed among three families, were recorded at the swamp. Hylidae was the most numerous family, followed by Leptodactylidae and Bufonidae. Statistical analysis detected significant difference in vertical distribution of hylids. Species of three families used different microhabitats at the swamp. Vertical and horizontal distributions of nine species were influenced by environmental variables. The number of species was positively correlated with water depth. The smallest aggregations were observed in cold months and the largest, in hot and rainy months. The number of calling males of thirteen species was influenced by at least one environmental variable. Statistical analysis did not allow detection of significant differences among the onsets of species call activities, but significant differences between call activities peak and end were detected. Despite sharing reproductive resources, species had some level of overlap in all parameters searched and this suggests that spatial and temporal distributions were not determinant as a reproductive isolation mechanism of anuran species at the swamp.
Although tropical forest birds are known to prey upon small lizards and
frogs, no study has documented the attributes of vertebrate-eating birds or
whether birds prey opportunistically on the different elements of the
herpetofauna within tropical communities. This study is based on a 14-mo
investigation on avian diet, supplemented with a 3-y census of frogs and a
1-y census of lizards in a humid forest of central Panama. From 91 bird
species, 1086 regurgitates were collected, in which were found 75 lizards
and 53 frogs. Over 50% of the common, primarily insectivorous bird species
preyed upon lizards or frogs, with a mean frequency of 0.26
prey/sample. These birds (22 species, nine families) foraged on various
substrates from different strata of the forest, fed on invertebrates
averaging from 3.3 to 17.2 mm in length, weighed from 11 to 195 g, and had
bill lengths that varied from 12.2 to 49.8 mm. Based on a logistic
regression analysis, intensity of foraging at army-ant swarms was the
variable that best explained the likelihood that a bird species preyed upon
lizards, leading to a classification that was 91% correct. In contrast, bill
length and body length classified correctly 88% of the frog-eating birds,
which showed a fairly constant 1:7 bill length/body length ratio (as opposed
to a mean but highly variable 1:10 ratio in other species). A multiple
regression analysis showed that seasonal variation in intensity of lizard
predation was positively related to arthropod abundance except during the
breeding season when lizard intake decreased, presumably because nesting
birds did not follow ant swarms. Intensity of frog predation correlated with
frog abundance over time, the latter being inversely related to arthropod
availability. Ninety-seven per cent of all lizards and frogs identified in
the diet samples (n = 105) were from two genera, Anolis and
Eleutherodactylus, respectively. Prey size distribution in the regurgitates
suggested an optimal prey size of 33.5 mm snout-vent length (SVL) for
lizards and 14.5 mm SVL for frogs. Birds preyed opportunistically on the
different Anolis species, but almost exclusively upon juvenile
individuals. Abundances of the different Eleutherodactylus species
correlated with their predation rates, but these frogs represented only 10%
of all the frogs observed during the censuses. The two most common local
anurans, Colostethus
flotator and Bufo
typhonius, were not taken by any bird
species.
Biodiversity of insects is threatened worldwide. Here, we present a comprehensive review of 73 historical reports of insect declines from across the globe, and systematically assess the underlying drivers. Our work reveals dramatic rates of decline that may lead to the extinction of 40% of the world's insect species over the next few decades. In terrestrial ecosystems, Lepidoptera, Hymenoptera and dung beetles (Coleoptera) appear to be the taxa most affected, whereas four major aquatic taxa (Odonata, Plecoptera, Trichoptera and Ephemeroptera) have already lost a considerable proportion of species. Affected insect groups not only include specialists that occupy particular ecological niches, but also many common and generalist species. Concurrently, the abundance of a small number of species is increasing; these are all adaptable, generalist species that are occupying the vacant niches left by the ones declining. Among aquatic insects, habitat and dietary generalists, and pollutant-tolerant species are replacing the large biodiversity losses experienced in waters within agricultural and urban settings. The main drivers of species declines appear to be in order of importance: i) habitat loss and conversion to intensive agriculture and urbanisation; ii) pollution, mainly that by synthetic pesticides and fertilisers; iii) biological factors, including pathogens and introduced species; and iv) climate change. The latter factor is particularly important in tropical regions, but only affects a minority of species in colder climes and mountain settings of temperate zones. A rethinking of current agricultural practices, in particular a serious reduction in pesticide usage and its substitution with more sustainable, ecologically-based practices, is urgently needed to slow or reverse current trends, allow the recovery of declining insect populations and safeguard the vital ecosystem services they provide. In addition, effective remediation technologies should be applied to clean polluted waters in both agricultural and urban environments.
The seed dispersal system of a neotropical tree, Cabralea canjerana (Meliaceae), was studied in two forested areas in southeastern Brazil. The first study site, Parque Estadual Intervales (PEI), is a 49,000-ha reserve composed mostly of old-growth Atlantic rain forest. The second site, Mata de Santa Genebra (MSG), is a 250-ha fragment of old-secondary semideciduous forest whose present bird fauna differs markedly from the original, in part as a consequence of forest fragmentation. At PEI 35 bird species ate the diaspores of C. canjerana. Black-tailed tityra (Tityra cayana, Tyrannidae) was the main seed disperser, but several other species were also important seed dispersers. In contrast, at MSG C. canjerana diaspores were eaten by 14 bird species. At this area, the red-eyed vireo (Vireo olivaceus, Vireonidae) was the most important seed disperser, but it was also a ‘waster’ which dropped seeds beneath parent plants, or carried them to sites unsuitable for germination. At PEI, exposed seeds on the forest floor were heavily preyed upon by rodents and insects. Insects destroyed mainly seeds deposited near to parent plants. Insect predation was less intense at MSG than at PEI. The rodent density at MSG was unusually small, and part of the post-dispersal seed predation may be done by terrestrial birds, such as doves and tinamous, which are especially common at MSG. Some of the differences recorded between the seed dispersal systems of C. canjerana at PEI and MSG may have been the result of the fragmentation and isolation of the latter area.
An adaptable and highly variable species, the Bright-rumped Attila ranges across the whole breadth of tropical America and from sea level up to 6,000 or 7,000 feet. It inhabits not only rain forests and deciduous woodland but often enters plantations and clearings with scattered trees. It is usually seen alone, high in the trees.
Its diet includes insects, small lizards, tiny frogs, fruits, and arillate seeds. Sometimes it catches small creatures from pasture grass or low weeds in plantations. Occasionally it forages with army ants.
Both sexes deliver clear, melodious, far-carrying songs or calls, in Costa Rica chiefly from February to April.
A nest found in the Caribbean lowlands of Costa Rica was a bulky open cup, situated 32 inches above the ground on a little shelf in the deep embayment between two high plank buttresses of a great tree at the edge of a cacao plantation. In 1967 this nest held four nestlings that flew on 24 April. A new nest built in the very same site in the following year contained four newly laid eggs on 13 March. They resembled the eggs of certain American flycatchers more than those of other cotingas.
Only the female incubated. During an all-day watch, her sessions ranged from 63 to 111 minutes, her recesses from 13 to 60 minutes, and she covered her eggs for 67% of the time. When she returned to her nest she was escorted closely by her mate. While sitting, she often sang a long-drawn, subdued nest song, or in a louder voice answered her mate with a song similar to his. The incubation period was no less than 18 days.
Newly hatched nestlings had flesh-coloured skin shaded by dark grey down that was abundant for a passerine. The interior of the mouth was bright orange-yellow. Even before they were feathered, these nestlings gave weaker-voiced imitations of their parents' calls or songs, and soon they could reproduce much of the adults' repertoire. The nestling period was about 18 days.
Only the female brooded the nestlings, but the two parents took about equal parts feeding them, chiefly with small lizards, tiny frogs, and a few insects, brought one at a time in the parents' bills.
The parents defended the territory around their nest, vigorously attacking intruders of their own species.
Detailed information about the range and composition of the diets of free-ranging wild animals is extremely limited. The nutritional protocols of wildlife-conservation programmes or the maintenance of wild animals in captivity are based on a limited understanding of species’interactions and habitat strategies. More detailed information on diet can be obtained from direct observations of feeding, analysis of leftover food around feeding or nest/den sites, or identification of components in the digesta at various stages through the digestive tract, including faeces or pellets. In order to gather more specific data from animals it is essential that the food that has been consumed can be identified, even if it only appears as fragments within the digesta, faeces or pellets. The amounts eaten and how various foods respond to the rigours of digestion are also important; for example, soft prey items may be under-represented or non-existent at the end of the digestion process. This article describes various methods that can be used to identify the food items consumed by animals and suggests studies that can be carried out in both the wild and captivity to facilitate the development of a detailed and species-specific reference bank of food items.
The nest and eggs of the Ochraceous Attila Attila Torridus in South-West Ecuador with notes on parental care
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Aves se alimentando de Alchornea glandulosa (Euphorbiaceae) na Mata Atlântica do sudeste do Brasil
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Vitreorana uranoscopa. Predation by Attila rufus
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