Bird tolerance to humans in open tropical ecosystems

AbstractAnimal tolerance towards humans can be a key factor facilitating wildlife–human coexistence, yet traits predicting its direction and magnitude across tropical animals are poorly known. Using 10,249 observations for 842 bird species inhabiting open tropical ecosystems in Africa, South America, and Australia, we find that avian tolerance towards humans was lower (i.e., escape distance was longer) in rural rather than urban populations and in populations exposed to lower human disturbance (measured as human footprint index). In addition, larger species and species with larger clutches and enhanced flight ability are less tolerant to human approaches and escape distances increase when birds were approached during the wet season compared to the dry season and from longer starting distances. Identification of key factors affecting animal tolerance towards humans across large spatial and taxonomic scales may help us to better understand and predict the patterns of species distributions in the Anthropocene.</jats:p

Relationship between bird-of-prey decals and bird-window collisions on a Brazilian university campus

Bird-window collisions are a dramatic cause of bird mortality globally. In Latin America, statistics are generally very scarce and/or inaccessible so the frequency of such incidents is still poorly understood. Nevertheless, civilians have applied preventive methods (e.g. adhesive bird-of-prey decals) sparsely but, to our knowledge, no study has evaluated their effectiveness in Brazil. Here, we estimated the mortality rate of bird-window collisions and tested the effectiveness of bird-of-prey decals at preventing such accidents. We undertook daily searches for bird carcasses, presumably resulting from window collisions, near all buildings on a university campus over seven months. Adhesive bird-of-prey decals were then applied to the two buildings with the highest mortality rates and surveys continued for over 12 more months. The mortality rates before and after the application of decals and between seasons were then compared using Friedman test. We recorded 36 collisions, 29 around the two buildings with the highest collision rates 19 prior and 10 after our intervention with associated collision rates of 0.08 and 0.04 collisions/day. Although mortality was reduced by almost half, this difference was not statistically significant. The Blue-black grassquit, Volatinia jacarina (Linnaeus, 1766), and Ruddy ground dove, Columbina talpacoti (Temminck, 1810) suffered the highest number of collisions, followed by the Rufous-collared sparrow, Zonotrichia capensis (P. L. Statius Müller, 1776). Our bird-of-prey decals and efforts were insufficient to prevent or dramatically reduce the number of bird-window collisions. Therefore, we recommend that different interventions be used and additional long-term studies undertaken on their efficacy

Experimental birds managment in anthropic areas, using nest-boxes

Use of nest-boxes for management of cavity nesting birds in anthropic areas can give good results. In November 1987, data collection begun in UNICAMP, Campinas (São Paulo), with the objective of favouring establishment and increase in urban bird communities. The House Wren (Troglodytes aedon Viellot. 1807) and House Sparrow (Passer domesticus Linnaeus, 1758) used the nest boxes for reproduction. Nests were collected and analysed (weight, used materials, incubation chamber materials, nest form). House Sparrow used thin materials, like straw, paper and plastic, while house wren used heavy materials, like sticks, wire and tabs of soff drink cans. The nest-boxes offered favorable conditions to bird reproduction and protection in disturbed areas, and showed signs of leading to increase in diversity of species, that might use this nest-boxes for reproduction in the future.749758Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Factors affecting escape distance in birds

ABSTRACT The flight initiation distance has been used either to understand the cost-benefit trade-offs related to the risk of predation or as an important tool for wildlife managers. Although this variable is well-discussed for temperate regions, it is still poorly known in the Neotropics. Here we analyze the escape behavior of birds from southeastern Brazil, comparing an urban to a non-urban area. We tested for the influence of sites (urban vs. non-urban area), approaching (by one vs. two people), daytime (morning vs. afternoon), seasons (breeding vs. non-breeding) and body mass on the determination of the initial (FID) and final (FFD) flight distances across different bird species. We predict that FID will be greater in rural areas and under a greater threat (higher number of predators approaching) in the afternoon and in the non-breeding season. We also expect a direct relationship between body mass and FID and between FID and FFD. We sampled 11 species after measuring 331 escape behaviors, and we confirmed our predictions for sites (five species), daytime (one species) and rejected our premise about seasons for one species. Mean FID was strongly affected by body mass, and directly affected FFD. Adjustments in FID are, most likely, an important adaptive trait in urban habitats and may partially explain the predominance of species with higher ecological plasticity in cities

Interhabitat variation in diplochory : seed dispersal effectiveness by birds and ants differs between tropical forest and savanna

Diversified assemblages of frugivores interact with fruits/seeds in tropical environments. Species within assemblages vary largely in body size, abundance, seed treatment and places of seed deposition, with possible delayed consequences for seed dispersal and plant regeneration. The variable outputs of the interaction may be magnified when considering different habitats and diplochoric plants that include more than one agent in subsequent steps of dispersal. Here we compared the contribution of birds and ants to the seed dispersal effectiveness (SDE) of two species of Etythroxylum shrubs that grow in Atlantic forest and Cerrado savannas in Brazil. We compared the number of seeds dispersed by each one of 16 bird and 30 ant species and their delayed consequences for seed germination and seedling survival combining experimental and modeling approaches. We observed shifts in the role of different dispersal agents between habitats, with birds being more important in the forest while ants are highlighted in the savanna. Quantity and quality components of SDE were not correlated, but large body size emerged as an important trait driving the quantity (birds) and quality (ants) components of SDE. A high diversified assemblage of dispersal agents does not always result in redundant effects for SDE, with some species consistently providing better dispersal than others and several opportunities for complementary effects. Therefore, even in diversified assemblages operating in diplochoric dispersal systems, there is the opportunity for ecological specialization384857CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP478938/2011-0; 302219/2017-0não tem02/12895-8; 2014/23141-1; 2017/16645-

Testing camera traps as a potential tool for detecting nest predation of birds in a tropical rainforest environment

Identification of the predators of bird nests is essential to test ecological and evolutionary hypotheses and to make practical management decisions. A variety of nest monitoring devices have been proposed but many remain difficult to set up in the field. The aim of this study was to test camera traps as a potential tool to study predation of natural nests in a tropical rainforest environment. Specifically, we registered the predators, assessed their size range, and we compared the use of one and two cameras per nest. Of 122 nests from 24 bird species, 45 (37%) were depredated, and the cameras recorded the predator species in 29 of the total of depredated nests (64%). We identified predators in eight of 16 depredated nests (50%) in which we used one camera trap per nest, and we identified predators in 21 of 29 depredated nests (72%) when we used two camera traps per nest. The predators included six species of birds and six species of mammals, with body masses varying from 20 g to 16.5 kg. Causes for 10 of the 16 detection failures were identified and are discussed. These results suggest that camera traps are viable tools to investigate nest predation in a tropical rainforest area