Responses of incubating hooded plovers (Thinornis rubricollis) to disturbance

Hooded Plovers (Thinornis rubricollis) and recreationists co-occur on the ocean beaches of southern Australia, and it has been suggested that disturbance of the breeding birds by humans constitutes a conservation problem. This study examines whether humans disturb incubating Hooded Plovers and places that disturbance in context with naturally occurring disturbances. Incubating Hooded Plovers encountered and responded to a variety of human and natural stimuli. The most common response involved leaving the nest for a period of time (an "absence"), and humans were responsible for 33.1% of time spent off nests. The response rates of incubating birds varied with the type of stimulus, with higher than expected response rates to two species of potentially predatory birds. About 17% of encounters with potential causes of disturbance occurred while birds were already responding to other disturbance, and this prolonged the return to the nest. Absences from the nest that were not apparently caused by disturbance were shorter and less frequent than those caused by external disturbance stimuli. Nest habitat influenced the response to encounters with humans, and on average foredune nests suffered the greatest decrease in attendance per encounter. This study has confirmed that human disturbance is more frequent than natural disturbances, and that humans decrease nest attendance substantially and more than any other source of disturbance.

Unauthorised human use of an urban coastal wetland sanctuary: current and future patterns

Urban expansion brings profound impacts and challenges to many ecosystems, including wetlands. Unauthorised public access to wetland sanctuaries can lead to a number of management problems, such as increasing disturbance to migratory shorebirds. We investigate unauthorised human use of a coastal urban wetland located in Melbourne, Australia, and use current results to predict future patterns of visitation under different management and urban development scenarios. Despite being officially closed to the public, 20.8% of the 574 ha wetland experienced human intrusions during the sampling period. These were most frequent in the section which directly abuts residential development where over 50% of the wetland experienced intrusions. The most frequently observed activities were walking (4.8 ± 4.9 intrusions per observation day), dog walking (8.5 ± 4.5), cycling (3.0 ± 1.8) and motorised trail bike riding (2.5 ± 1.0). There were significant negative relationships between the occurrence of intrusions and distance from the wetland boundary and access points. Walkers and dog walkers were likely to intrude more deeply into the wetlands than other users. We predict that once residential development is completed around the entire perimeter of the wetland that 48% of the total area will be subject to intrusions. This will increase to 58.8% if internal management tracks are opened for public use. We recommend that the current access policy is maintained, and compliance is enhanced through education and additional physical barriers. © 2006 Elsevier B.V. All rights reserved.

Stakeholder knowledge of threatened coastal species; the case of beach-goers and the Hooded Plover Thinornis rubricollis

One way of measuring pre-existing knowledge of a threatened species and its circumstances is to measure the degree of surprise expressed by stakeholders in relation to factual statements regarding the species. Beach-goers (n = 684) were surveyed in regard to their knowledge of the beach-dwelling, threatened, Hooded Plover Thinornis rubricollis, a coastal obligate in south eastern Australia. Principle components analysis revealed that respondents’ degree of knowledge could be categorized as involving ‘chick (flightless young) ecology’ and ‘human impacts’ (threatening processes). Respondents were more surprised by aspects of chick ecology than by threatening processes (F1,514 = 460.446, p < 0.001). Prior knowledge of the species was associated with less surprise at factual statements. Therefore, priorities for further education should focus on linking threats with chick ecology, particularly because an understanding that chicks are not stationary within fenced areas is critical to the interpretation and effectiveness of current signage used to mitigate human impacts.

North or south? Phylogenetic and biogeographic origins of a globally distributed avian clade

Establishing phylogenetic relationships within a clade can help to infer ancestral origins and indicate how widespread species reached their current biogeographic distributions. The small plovers, genus Charadrius, are cosmopolitan shorebirds, distributed across all continents except Antarctica. Here we present a global, species-level molecular phylogeny of this group based on four nuclear (. ADH5, FIB7, MYO2 and RAG1) and two mitochondrial (. COI and ND3) genes, and use the phylogeny to examine the biogeographic origin of the genus. A Bayesian multispecies coalescent approach identified two major clades (. CRD I and CRD II) within the genus. Clade CRD I contains three species (. Thinornis novaeseelandiae, Thinornis rubricollis and Eudromias morinellus), and CRD II one species (. Anarhynchus frontalis), that were previously placed outside the Charadrius genus. In contrast to earlier work, ancestral area analyses using parsimony and Bayesian methods supported an origin of the Charadrius plovers in the Northern hemisphere. We propose that major radiations in this group were associated with shifts in the range of these ancestral plover species, leading to colonisation of the Southern hemisphere.

Geographical variation and population structure in the White-rumped Sandpiper Calidris fuscicollis as shown by morphology, mitochondrial DNA and carbon isotope ratios

We studied the population structure of a high arctic breeding wader bird species, the White-rumped Sandpiper Calidris fuscicollis. Breeding adults, chicks and juveniles were sampled at seven localities throughout the species' breeding range in arctic Canada in 1999. The mitochondrial control region was analysed by DNA sequencing, feathers were analysed for carbon isotope ratios (C13/C12) by isotope ratio mass spectrometry, and morphological measurements were analysed using principal component analyses, taking the effect of sex into account (identified by molecular genetic methods). In general, our results support the notion that the White-rumped Sandpiper is a monotypic species with no subspecies, and most of the morphological and genetic variation occurs within sites. Nevertheless, some differences between sites were found. Birds from the two northernmost sites (Ellesmere and Devon Islands) had relatively longer bill and wing and shorter tarsus than birds sampled further south, possibly reflecting genetic differences between populations. The carbon isotope ratios were higher at the easternmost site (Baffin Island), revealing differences in the isotope content of the food. The mtDNA sequences showed no significant differentiation between sites and no pattern of isolation-by-distance was found. Based on the mtDNA variation, the species was estimated to have a long-term effective population size of approximately 9,000 females. The species shows no clear evidence of any population expansion or decline. Our results indicate that carbon isotope ratios, and possibly also certain mtDNA haplotypes, may be useful as tools for identifying the breeding origin of White-rumped Sandpipers on migration and wintering sites.

Challenges within the annual cycle of long-distance migratory waders along the East Asian-Australasian flyway

 The thesis focuses on the conservation of migratory shorebirds, particularly in this part of the world. Loss of habitats is one of the greatest threats and prioritizing the conservation of these habitats is of great importance to the future of these species.

Loss of periodicity in breeding success of waders links to changes in lemming cycles in Arctic ecosystems

Lemming population cycles in the Arctic have an important impact on the Arctic food web, indirectly also affecting breeding success in Arctic-nesting birds through shared predators. Over the last two decades lemming cycles have changed in amplitude and even disappeared in parts of the Arctic. To examine the large scale effect of these recent changes we re-analysed published data from the East Atlantic Flyway (EAF), where a relationship between lemming cycles and wader breeding success was earlier found, and new data on breeding success of waders in the East Asian-Australasian Flyway (EAAF). We found that 1) any long-term periodicities in wader breeding success existed only until the year 2000 in the EAAF and until the 1980s in the EAF; 2) studying these patterns at a smaller spatial scale, where the Siberian-Alaskan breeding grounds were divided into five geographical units largely based on landscape features, breeding success of waders from the EAAF was not correlated to an index of predation pressure, but positively correlated to Arctic summer temperatures in some species. We argue that fading out of lemming cycles in some parts of the Arctic is responsible for faltering periodicity in wader breeding success along both flyways. These changed conditions have not yet resulted in any marked changing trends in breeding success across years, and declining numbers of waders along the EAAF are therefore more likely a result of changing conditions at stop-over and wintering sites.

Home range, habitat use and movements by the little raven (Corvus mellori) in a coastal peri-urban landscape

Context In peri-urban environments, high availability of anthropogenic resources may result in relatively high abundances of some species, with potentially negative implications for other native biota. Effective management of such impacts requires understanding of the spatial ecology of problem species. However, home range and habitat use have not been described for the little raven (Corvus mellori), a superabundant native predator that occurs in urban and natural habitats, including those where threatened shorebirds breed. Aims The aim of this study was to provide basic information on little raven home range, habitat use and movements in a coastal peri-urban landscape. Methods Between October 2011 and January 2012 we radio-tracked 20 little ravens captured in a coastal wetland (near Melbourne, Australia). Key results Little ravens were highly mobile, moving up to 9.9km in an hour (median≤2km), and had large ranges: Minimum Convex Polygons were 1664-9989ha (median≤3362ha). Although most birds used both anthropogenic and natural habitats, some birds strongly selected for coastal wetland habitat. Birds used multiple roosts during the study period, most of which occurred in grassland (58.7%) or urban (22.3%) areas. Movement of up to 8.3km (median≤2.2km) between roosts during the night was also detected. Conclusions Ravens were highly mobile and used large home ranges and a variety of habitats, with habitat preferences varying between birds. Implications Considering the large home ranges and inter-individual variation in habitat preferences of little raven populations, localised management to reduce their impacts on breeding shorebirds is unlikely to be successful. Journal compilation

Long incubation bouts and biparental incubation in the nomadic Banded Stilt

Parental care strategies have been widely investigated in shorebirds that undertake long-distance regular migrations. In contrast, virtually nothing is known of the parental care of nomadic, opportunistically breeding shorebirds, although the irregular and short-lived nature of their breeding potentially accentuates the trade-offs between investment in successive clutches and between the sexes. We investigated the incubation behaviour of the nomadic, opportunistically breeding Banded Stilt (Cladorhynchus leucocephalus). Seven nests, filmed continuously with day–night cameras over 2–7 days, revealed that both sexes contributed to incubation, with males apparently the sole carer during hatching and early brood-rearing; this is a possible adaptation, which enables females to quickly produce a second clutch if favourable conditions persist. All incubator changeovers occurred after dark; incubation shifts averaged 44.8 ± 10.9 (s.e.m.) h (n = 11, 17.5–139.6 h), the longest recorded for any shorebird. Incubation constancy averaged 96.5%; this high value is possibly an adaptation to high predation and the need for rapid embryonic development in the face of ephemeral resources for breeding. Long incubation shifts may be explained by extended foraging trips to distant areas of the partially inundated salt-lake surface, where food resources had been concentrated by wind-driven water movement.

Sharing the load: role equity in the incubation of a monomorphic shorebird, the masked lapwing (Vanellus miles)

Sex roles during incubation vary dramatically in socially monogamous shorebirds. The "incubator conspicuousness" hypothesis posits that, for biparentally incubating and sexually dimorphic birds, the more conspicuous sex should incubate when visually foraging predators are inactive, and in many ecosystems this is at night. Therefore, sexually monomorphic species should share incubation equitably throughout the day and night. We examined incubation patterns in Masked Lapwings Vanellus miles and found that the contribution of the sexes to incubation was equitable. Another measure of incubation behavior, bout duration, was similar between the sexes; male bout durations were slightly shorter than for females. This finding is consistent with the predictions of the incubator conspicuousness hypothesis, although other processes may also explain equitable care.

Continental-scale decreases in shorebird populations in Australia

Decreases in shorebird populations are increasingly evident worldwide, especially in the East Asian–Australasian Flyway (EAAF). To arrest these declines, it is important to understand the scale of both the problem and the solutions. We analysed an expansive Australian citizen-science dataset, spanning the period 1973 to 2014, to explore factors related to differences in trends among shorebird populations in wetlands throughout Australia. Of seven resident Australian shorebird species, the four inland species exhibited continental decreases, whereas the three coastal species did not. Decreases in inland resident shorebirds were related to changes in availability of water at non-tidal wetlands, suggesting that degradation of wetlands in Australia’s interior is playing a role in these declines. For migratory shorebirds, the analyses revealed continental decreases in abundance in 12 of 19 species, and decreases in 17 of 19 in the southern half of Australia over the past 15 years. Many trends were strongly associated with continental gradients in latitude or longitude, suggesting some large-scale patterns in the decreases, with steeper declines often evident in southern Australia. After accounting for this effect, local variables did not explain variation in migratory shorebird trends between sites. Our results are consistent with other studies indicating that decreases in migratory shorebird populations in the EAAF are most likely being driven primarily by factors outside Australia. This reinforces the need for urgent overseas conservation actions. However, substantially heterogeneous trends within Australia, combined with declines of inland resident shorebirds indicate effective management of Australian shorebird habitat remains important.

O uso de praias arenosas com diferentes concentrações humanas por espécies de aves limícolas (Charadriidae e Scolopacidae) neárticas no sudeste do Brasil

As aves migratórias podem reconhecer humanos e animais domésticos como possíveis predadores, alterando seus padrões de abundância e comportamento de formação de bandos. O objetivo do presente estudo foi comparar a abundância de aves migratórias neárticas, a freqüência de bandos e o número médio de aves por bando em áreas com alta e baixa concentração humana em uma região costeira de praia arenosa no sudeste do Brasil. As aves, pessoas e cães foram contados mensalmente entre novembro de 2006 a abril de 2007. Foram registradas seis espécies de aves (Arenaria interpres, Calidris alba, Calidris canutus, Calidris pusilla, Charadrius semipalmatus, Pluvialis dominica) nas duas áreas, no entanto somente C. canutus foi registrado exclusivamente na área com baixa concentração humana. Houve diferença significativa no número médio de pessoas e cães entre as áreas, mas não no número médio de aves. Não houve correlação entre o número de humanos e aves, e entre cães e aves. Adicionalmente, não houve diferença significativa na freqüência de bandos e número de indivíduos por bando entre as áreas. Os resultados deste estudo destacaram a sensibilidade de C. canutus na área com alta concentração humana e a necessidade de futuras investigações que determinem os limites máximos de concentração de pessoas e cães domésticos que as aves migratórias neárticas podem tolerar para a tomada de ações de proteção em áreas costeiras com ocupação humana.

Heterospecific sociality of birds on beaches from southeastern Brazil

Studies on the sociality of heterospecific assemblages of birds have promoted a greater understanding of the types of interactions and survivorship between coexisting species. This study verified the group compositions in bird assemblages and analyzed the sociality of migratory and resident species on sandy beaches of southeastern Brazil. A transect was established on the median portion of beaches and all the groups of bird species (monospecific, heterospecific) and solitary individuals were registered four days per month from November 2006 to April 2007. The sociality of each species was calculated by its frequency in heterospecific groups, its proportional number of contacts with other species in heterospecific groups, and the number of species that it associated with. Semipalmated Sandpiper Calidris pusilla (Linnaeus, 1766) and Semipalmated Plover Charadrius semipalmatus Bonaparte, 1825 (both migratory) had the highest degree of sociality and did not show a preference to associate with either residents or migratory species. Sanderling Calidris alba (Pallas, 1764) (migratory) occupied the third position in the sociality rank and associated with migratory species frequently. Southern Caracara Carara plancus (Miller, 1777) and Black Vulture Coragyps atratus (Beschstein, 1793) (both resident) were uniquely found among heterospecific groups with necrophagous and resident species. Kelp Gull Larus dominicanus Lichtenstein, 1823 (resident) associated more frequently with resident species. The sociality in assemblages of birds may promote advantages such as an increased collective awareness in dangerous situations and indication of sites with abundant food sources.

Distribuição e conservação de aves migratórias neárticas da ordem Charadriiformes (famílias Charadriidae e Scolopacidae) no Brasil

Apesar dos esforços de pesquisa nos últimos anos, muitos dos aspectos das migrações dos charadrídeos e escolopacídeos no Brasil permanecem desconhecidos. A maioria dos estudos em escala local ou regional revela a necessidade de uma síntese das informações em escala espacial adequada para facilitar a detecção dos grandes padrões de movimento destas espécies no país. Desta forma, esta tese teve como objetivo geral identificar os padrões de distribuição e migrações das espécies de aves das famílias Charadriidae e Scolopacidae que se reproduzem no hemisfério norte e usam o território brasileiro durante as suas migrações, visando desenvolver estratégias para a conservação do grupo. Como objetivos específicos, caracterizar as principais rotas migratórias para estas espécies; identificar as áreas críticas para a conservação utilizando os critérios propostos pela metodologia das AIAs e ACBs; avaliar o estado de conservação atual das áreas críticas para a conservação destas espécies de acordo ao Sistema Nacional de Unidades de Conservação; avaliar se as áreas críticas são parte das áreas prioritárias para a conservação da biodiversidade brasileira; aplicar os critérios da Convenção de Ramsar e da WHSRN para identificar áreas críticas para conservação destas espécies. A base de dados foi estabelecida a partir de levantamento bibliográfico; consultas às coleções científicas de museus brasileiros e estrangeiros; utilização de bases de dados de recuperações de anilhas brasileiras e norte-americanas; dados cedidos por pesquisadores do Brasil, Argentina e Estados Unidos; dados de campo coletados pessoalmente no Pantanal (MS), litoral dos estados do Maranhão e Rio Grande do Sul. Entre os principais resultados, 19 das 24 espécies possuem um conjunto importante de dados, com as demais sendo ocasionais ou com poucas informações. Há uma maior concentração de dados na região costeira do país, com menor cobertura de áreas do interior. A Amazônia Ocidental mostrou-se a menos conhecida nos aspectos abordados, embora seja a via de passagem para algumas das espécies analisadas. O litoral entre a foz do Amazonas e São Luiz, no Maranhão foi a principal área de concentração em termos numéricos. A costa do Rio Grande do Sul foi o segundo local com maior destaque nas análises. Quinze espécies foram registradas em todos os meses do ano, demonstrando que nem todos os indivíduos migram anualmente para o hemisfério norte. Considerando as rotas globais, 8 espécies utilizam a rota do Atlântico e 10 a rota do Mississipi ou do centro da América do Norte. As outras 6 possivelmente utilizam-se das duas rotas. O conhecimento na utilização das 5 rotas propostas por Antas (1983) durante a migração sul-norte indicou que algumas espécies têm registros no interior da Amazônia, período em que possivelmente seus habitats estariam inundados. O padrão de chegada na migração norte-sul no Brasil é entre agosto e outubro, com incremento a partir de setembro. A migração sul-norte ocorre entre meados de março e abril na maioria das espécies. Durante o período não reprodutivo existe um padrão de distribuição ao longo da costa utilizado por 9 espécies, outro continental para 7 espécies no interior e ainda um terceiro, difuso, encontrado em 5 espécies que se distribuem tanto na costa quanto no interior do país. Foram identificadas 260 áreas críticas importantes para as espécies avaliadas. Observou-se que 72% das ACBs identificadas estão fora do SNUC. A sobreposição das ACBs com as Áreas Prioritárias para a Conservação revelou que 46% das primeiras estão sem indicação de importância neste programa. São elegíveis para os critérios da Convenção Ramsar 69 ACBs, enquanto 65 podem ser inseridas no programa da WHSRN. Entre as principais conclusões, o conhecimento de processos biológicos fundamentais à manutenção do ciclo de vida e o curso de suas migrações anuais, de parâmetros relacionados à mudas de penas, ganho de massa corporal, razão sexual e etária das populações migrantes são aspectos ainda insuficientemente detalhados para estas espécies no Brasil, e mesmo na América do Sul, assim como a necessidade de pesquisas que possam gerar estimativas e tendências populacionais, uma vez que em escala global várias destas espécies apresentam declínio populacional.