ABSTRACT Studies on the breeding biology of birds provide relevant infor-mation about their life history and allow the understanding of the ecological aspects that can influence their breeding success and population trends. Between October and February 2017 to 2020, we monitored nests of South American Snipe (Gallinagoparaguaiae) in a grassland under low density livestock pressure located in the Flooding Pampa, in north-eastern Buenos Aires Province, Argentina. We searched for nests by rope-dragging and monitored them regularly until either they hatched or failed. We measured each nest and its surrounding vegetation (including lateral and vertical visual obstruction readings), and distances to grassland edges. We analyzed nest-site preferences comparing nests vegetation to vegetation at random points, and estimated the apparent nest success and daily nest survival rate (DSR) of the species. We found 15 nests which had a mean clutch size of 2.8 eggs. Nests were built in ~60-centimeter-high grass clumps, and had more horizontal visual obstruction than random points. Only three nests were successful (apparent nest success = 20 %) and preda-tion was the main cause of nest failure. Nest DSR was 0.879, with a cumulative probability of survival of 8.6 % during the incubation period, which is low compared to similar species. We emphasize the need to study nest predators in the region and to continue studying avian populations breeding in these habitats, in order to shed light on the effect of habitat alteration on the population dynamics of these birds.

RESUMEN Los estudios de biología reproductiva de las aves proveen información importante sobre sus historias de vida y permiten comprender aspectos ecológicos que afectan su éxito reproductivo y sus tendencias demográficas. Desde octubre a febrero de 2017 a 2020 realizamos un monitoreo de nidos de Becasina de Bañado (Gallinagoparaguaiae) en un pastizal natural con baja carga ganadera en la Pampa Deprimida, noreste de la provincia de Buenos Aires, Argentina. Buscamos nidos mediante arrastre de soga y los monitoreamos hasta la fecha de eclosión o fracaso. Tomamos medidas de los nidos, la vegetación alrededor (incluyendo cobertura visual horizontal y superior) y distancias a los bordes de hábitat. Analizamos la selección de sitios de nidificación comparando la vegetación con la de puntos aleatorios, calculamos el éxito aparente y la tasa de supervivencia diaria (TSD) de la especie. Encontramos 15 nidos, con un tamaño promedio de puesta de 2.8 huevos. Los nidos estuvieron construidos entre pastos de ~60 cm de altura y presentaron mayor cobertura visual horizontal que los sitios aleatorios. Sólo tres nidos fueron exitosos (éxito aparente = 20 %) siendo la depredación la principal causa de fracaso. La TSD fue 0.879, calculando un éxito acumulado para la etapa de incubación de 8.6 %, que es bajo comparado con especies similares. Destacamos la necesidad de generar conocimiento sobre los depredadores de nidos en el pastizal pampeano y de continuar con estudios de las poblaciones de aves que reproducen en estos ambientes, con la finalidad de echar luz sobre el efecto de la alteración del hábitat en la dinámica poblacional de estas aves.

Abstract We report the presence of four species of waterbirds with partial leucism in the Lake of Zumpango, State of Mexico. The individuals observed with aberrant coloration were a hatchling White-faced Ibis (Plegadis chihi), an adult Common Gallinule (Gallinula galeata), an adult American Coot (Fulica americana) and an adult Killdeer (Charadrius vociferus). These are the first partial leucism records for these waterbirds in Mexico. The Lake of Zumpango is a wetland that presents high pollution levels and a high degree of anthropogenic disturbance, so future studies could contribute with knowledge about these color anomalies in the area.

Resumen Reportamos la presencia de cuatro especies de aves acuáticas con leucismo parcial en la Laguna de Zumpango, Estado de México. Los individuos que observamos, de coloración aberrante, fueron los siguientes: un polluelo recién eclosionado del ibis cara blanca (Plegadis chihi), un adulto de gallineta frente roja (Gallinula galeata), un adulto de gallareta americana (Fulica americana) y un adulto de chorlo tildío (Charadrius vociferus). Se trata de los primeros registros de leucismo parcial para estas especies de aves acuáticas en México. La Laguna de Zumpango es un humedal que presenta altos niveles de contaminación y un alto grado de perturbación antropogénica, por lo que estudios futuros podrían aportar conocimiento sobre los factores que ocasionan estas anomalías de coloración en el área.

Este estudio tuvo como propósito conocer la composición y estructura de las aves en Puerto Velero, en el departamento del Atlántico (Colombia). Se muestrearon dos coberturas (Manglar y Playa) realizando censos de aves, usando el método conteo por puntos. Las observaciones se hicieron de 06:00 a 10:00 y de 15:00 a 18:00 h y se registró la presencia y abundancia de todas las aves observadas. Se registró un total de 1.229 individuos pertenecientes a 33 especies y 17 familias. En la cobertura Manglar se observaron 28 especies y en la cobertura Playa se registraron 22. Las familias con mayor número de representantes fueron Scolopacidae (5 especies), Ardeidae y Charadriidae (4 especies cada una) y Tyrannidae (3 especies). Las especies abundantes en la zona de estudio fueron: Cathartes aura, Progne tapera, Charadrius wilsonia, Quiscalus mexicanus y Egretta thula. No hubo diferencias significativas entre la composición y abundancia de aves por cobertura. Aunque la composición de especies fue relativamente similar en ambos tipos de cobertura (61,26%), el valor del número de Hill indica que el Manglar fue la cobertura más importante con relación a la riqueza de especies. En Puerto Velero predominan aves con alto rango de distribución, pero las aves migratorias (8 familias en 4 órdenes) constituyen un componente importante de este grupo faunístico ya que son especies con requerimientos específicos en términos de disponibilidad de recursos para alimentarse, descansar y refugiarse. De igual manera, las especies residentes que se observaron cumplen un papel importante en términos de la funcionalidad ecológica y su contribución en procesos de regulación y soporte dentro del ecosistema.

The purpose of this study was to determine the composition and structure of birds in Puerto Velero, department of Atlántico, Colombia. Two bird ranges were sampled (mangrove and seashore) conducting bird census using the point count method. The observations were made from 06:00 to 10:00 h and from 15:00 to 18:00 h, local time, and the presence and abundance of all birds observed were recorded. A total of 1,229 individuals belonging to 33 species and 17 families were recorded. Twenty-eight (28) species were reported in the mangrove range and 22 species in the seashore range. The families with the greatest number of representatives were Scolopacidae (5 species), Ardeidae and Charadriidae (4 species each) and Tyrannidae (3 species). The most abundat species in the area of study were: Cathartes aura, Progne tapera, Charadrius wilsonia, Quiscalus mexicanus y Egretta thula. There were not significant differences between composition and abundance of birds per range. Although the composition of species was relatively similar in both ranges (61.26%), Hill's number value indicates that the mangrove range was the most important in relation to richness of species. High distribution range birds predominate in Puerto Velero, but migratory birds (8 families in 4 orders) are an important component of this fauna group as they are species with specific requirements in terms of availability of feeding, resting and refuge resources. Similarly, resident species observed play an important role in terms of ecological functionality and their contribution in the regulatory and support processes within the ecosystem.

Foram registradas as freqüências de ocorrências e as flutuações mensais das famílias Charadriidae e Scolopacidae ao longo de um transecto de 70 km de praia entre o Boqueirão Sul e o Boqueirão Norte na Ilha Comprida, estado de São Paulo, durante o período de um ano (Janeiro a dezembro de 2010). Um total de 12.153 indivíduos de aves foram contados com a maior abundância ocorreu entre outubro e abril e a mais baixa entre maio a setembro. Das 20 espécies registradas as mais abundantes foram Charadrius semipalmatus, Charadrius colaris, Vanellus chilensis e Tringa flavipes. As menos abundantes foram Tryngites subruficolis, Limosa haemastica,Tringa melanoleuca e Actitis macularia. Dezesseis espécies eram migrantes do Hemisfério Norte, duas migrantes do Hemisfério Sul, e duas residentes. Sete espécies foram registradas regularmente, cinco esporadicamente e oito foram ocasionais. Quatro espécies neárticas foram registradas em Junho e julho, provavelmente indicando a presença de indivíduos imaturos não reprodutores. O número de espécies e o número de indivíduos provavelmente flutuaram devido a migração ou movimentos entre as praias vizinhas. A praia da Ilha Comprida é um importante sítio de parada durante a migração para muitas aves de praia na costa Sul do estado de São Paulo. Por esse motivo, devem ser feitos esforços de preservação, especialmente tendo em conta a crescente pressão de desenvolvimento que ameaça essa região.

We recorded the frequency of occurrence and monthly fluctuations of Charadriidae and Scolopacidae along a 70km transect of beach between Boqueirão Sul and Boqueirão Norte north of Comprida island, São Paulo State over a 1-year period (Jan - 2010 to Dec - 2010). A total of 12.153 shorebirds were recorded. The greatest abundance occurred between October and April and the lowest occurred between May and September. The most abundant of the 20 species recorded were Charadrius semipalmatus, Charadrius colaris,Vanellus chilensis and Tringa flavipes. The least abundant wereTryngites subruficolis, Limosa haemastica, Tringa melanoleuca and Actitis macularia. Sixteen species were migrants from the Northern Hemisphere, two were migrants from the Southern Hemisphere, and two were residents. Seven species were recorded regularly, five were recorded sporadically, and eight were recorded occasionally. Four Nearctic species were recorded in June and July most likely indicating the presence of non-breeding immature. The number of species and the number of individuals probably fluctuated due to migration or movements between neighbouring beaches. The Comprida Island beach is important migration stopover and wintering sites for many shorebirds in south São Paulo and should be a focus of conservation efforts, especially given the increasing development pressure that threatens these areas.

Charadrius melodus es una especie migratoria en peligro de extinción. Cada año, la Laguna Madre recibe aves migratorias invernales, incluyendo a la especie antes mencionada, sin embargo su estabilidad se encuentra amenazada por el cambio de hábitat ocasionado por el dragado que se está realizando en la zona. La falta de estudios sobre C. melodus durante el invierno en la Laguna Madre, motivó la realización del trabajo (diciembre 2009-marzo 2010). Los objetivos fueron: 1) determinar la importancia del área invernal, 2) describir la etología y preferencias de sustrato en la alimentación, 3) analizar ítems alimenticios potenciales y describir la diversidad simpátrica asociadas a C. melodus. Se observaron 99 individuos durante el muestreo. Las pruebas de Cochran y Kendall presentaron una alta significancia de la especie con un tipo de sustrato y las pruebas de signos utilizando una distribución binomial indicaron que existe una alta preferencia hacia un tipo de sustrato. La mayor actividad registrada durante el periodo de muestreo fue la de alimentación. Los recursos alimenticios encontrados en las muestras de sedimentos fueron larvas de Dípteros. Las especies simpátricas a C. melodus pertenecen al orden Charadriiformes con dos familias: Charadriidae nueve especies y Scolopacidae dos especies. Por la importancia de la zona, se recomienda proteger Boca Ciega, pues representa sitios de alimentación, protección y descanso para el Chorlo melódico.

The Piping Plover (Charadrius melodus) is a migratory endangered species that arrives, along with a great number of other winter migratory birds, to Boca Ciega every year. In spite of the importance of this ecosystem, these species, are threatened by the current habitat change caused by the dredging activities in the area. With the aim to generate new information about the importance of this area during winter, we studied C. melodus activities during the winter season in Laguna Madre, from December 2009 to March 2010. Our objectives were: 1) determine the importance of the area during winter, 2) describe C. melodus ethology, feeding substrate preferences and food items, 3) to analyze and describe the sympatric diversity associated with C. melodus. A total of ninety nine individuals were observed during the monitoring. The Cochran and Kendall test showed a high significance of the species with the substrate and signs tests using a binomial distribution that indicated a high preference for algal type of substrate. The highest activity recorded for this species during this winter season was feeding. The principal food items found in sediments were larvae of Diptera: Chironomidae and Ephydridae. The sympatric species of C. melodus were two families of Charadriiforms: Scolopacidae (nine species) and Charadriidae (two species). We concluded that this is an important area for feeding, protection and rest sites for this species, and its protection and management is recommended.

O monitoramento a longo prazo das comunidades de aves, disponibilizou dados fundamentais na formulação de modelos de populações, tornando-se uma ferramenta valiosa na conservação da biodiversidade. As aves aquáticas do Saco da Fazenda foram monitoradas mensalmente através de três censos, em um mesmo dia, durante o período de janeiro de 1996 a dezembro de 2005, sendo adotado o número médio de aves por mês, como uma medida padrão da abundância. Das 50 espécies registradas, 34,0% foi regular nos censos, 12,0% sazonalmente e 54,0% de ocorrência ocasional. As aves residentes representaram 72,0% das espécies, as visitante sazonal do hemisfério norte (22,0%), das visitantes do sul da América do Sul (4,0%) e de uma espécie de ocorrência incerta no país. Dessas, sete são aves marinhas costeiras, 39 de hábitos limícolas e quatro espécies habitantes das bordas ou visitantes originários da Mata Atlântica. As famílias Ardeidae, Scolopacidae, Laridae e Charadriidae contribuíram com 64,0% das espécies, onde Phalacrocorax brasilianus (Gmelin, 1789) e Larus dominicanus Lichtenstein, 1823 foram dominantes nos censos. Apesar das flutuações sazonais, a abundância média mensal da avifauna não apresentou diferenças, mas quando confrontados os 10 anos de censos, esses foram significativamente diferentes. Enquanto que o índice de diversidade apresentou valores mensal e anual significativamente diferentes, a equitabilidade flutuou moderadamente entre os anos de coleta, mantendo-se estatisticamente semelhante, foram mensalmente diferente. Estudo como o presente, envolvendo comunidades de aves aquáticas em uma série temporal de 10 anos interruptos, são raros, mas reforçam a necessidade de considerar a época do ano, horário e o número de censos para determinar adequadamente o tamanho das populações. O contínuo monitoramento desses agrupamentos poderá contribuir na compreensão das interações entre as espécies e na avaliação da importância das populações do estuário, no contexto regional.

Long-term monitoring of bird communities provides fundamental data to build population models which are valuable instruments to biodiversity conservation. The Saco da Fazenda aquatic avifauna was monitored monthly through three-daily visual censuses from January 1996 to December 2005, adopting the monthly average number of birds as a standard measurement of abundance. A total of 50 species were registered, and considering the frequency of occurrence, 34.0% were considered regular, 12.0% seasonal and 54.0% occasional. Resident birds represented 72.0% of the total species observed, seasonal visitors from the North Hemisphere (22.0%), South America visitors (4.0%) and a single species representing a possible new occurrence for Brazil. Seven were classified as shorebirds, 39 were limnic waterbirds and four species were border inhabitants or visitors coming from the Atlantic Forest. The families Ardeidae, Scolopacidae, Laridae and Charadriidae contributed with 64.0% of the species, being Phalacrocorax brasilianus(Gmelin, 1789) and Larus dominicanus Lichtenstein, 1823 the predominant ones. Despite the seasonal fluctuations observed, monthly average abundances of avifauna presented no differences, but when comparing the 10-year censuses data set, abundances were significantly different. While the diversity index showed significant differences for both monthly and annual values, the evenness index showed moderate fluctuations along the sampled years, remaining statistically similar but monthly distinct. Long-term uninterrupted studies involving waterbird communities are unique and support the need to consider seasonality, time of the day and the number of censuses to adequately determine population's size. The continuity of such long-term monitoring, could give a substantial contribution to understand interactions among species and to evaluate the importance of the estuarine populations, in a regional context.

This study was carried out at El Paraíso lagoon, Lima, Peru, from April 1999 to April 2000. The main goals was determinated the birds specific diversity, the population density of main cinegetic bird families and the determination of the most important microhabitats for the studied groups. 81 birds species (19 species are new for the area) were reported, distribuited in 62 generas and 35 families. 46% of the diversity is given for the following families: Scolopacidae (14%), Ardeidae (10%), Laridae (7%), Anatidae (5%), Charadriidae (5%) and Columbidae (5%). The Rallidae family is the most abundant and is represented for two species Gallinula chloropus "Common Moorhen" y Fulica ardesiaca "Slate-colored Coot". It is given recommendations for the conservation of the area.

Este estudio se realizó en la laguna El Paraíso, departamento de Lima, Perú, de abril de 1999 a abril del 2000. Tuvo como objetivos la determinación de la diversidad específica en aves; la densidad poblacional de las principales familias de uso cinegético y la determinación de los microhábitats más importantes para los grupos evaluados. Se reportaron 81 especies de aves las cuales pertenecen a 62 géneros y a 35 familias. En esta cifra se reportan 19 especies nuevas para el área de Paraíso; el 46% de la diversidad de aves está dada por las familias Scolopacidae (14%), Ardeidae (10%), Laridae (7%), Anatidae (5%), Charadriidae (5%) y Columbidae (5%). La familia Rallidae es la más abundante y está representada por dos especies Gallinula chloropus "polla de agua" y Fulica ardesiaca "gallareta", siendo la primera más numerosa. Asimismo, se dan las recomendaciones para la conservación del área.

Todos os anos milhares de aves limícolas e migratórias invernam ao longo da costa da América do Sul, entre setembro e abril, onde adquirem massa corpórea e realizam mudas para retornar aos sítios de reprodução. Estudos quali-quantitativos foram realizados na Área de Proteção Ambiental de Piaçabuçu, Alagoas, Brasil, através da contagem direta, objetivando o acompanhamento das flutuações sazonais da avifauna migrante. Foram registradas cinco espécies da família Charadriidae: Vanellus chilensis (Wagler, 1827); Pluvialis squatarola (Linnaeus, 1758); Charadrius semipalmatus Bonaparte, 1825; Charadrius collaris Vieillot, 1818 e Charadrius wilsonia (Ord, 1814) e cinco espécies da família Scolopacidae: Arenaria interpres (Linnaeus, 1758); Actitis macularius (Linnaeus, 1766); Catoptrophorus semipalmatus (Gmelin, 1789); Calidris pusilla (Linnaeus, 1766) e Calidris alba (Pallas, 1764). Pluvialis squatarola, Charadrius semipalmatus, Charadrius collaris, Arenaria interpres, Calidris pusilla e Calidris alba foram consideradas constantes (presentes em mais de 50% das observações). Charadrius semipalmatus e Calidris alba apresentaram os maiores índices de freqüência de ocorrência nos meses de novembro e dezembro e, março e setembro, respectivamente. A correlação de Spearman demonstra uma forte dependência na migração destas espécies. A fidelidade dessas aves a APA de Piaçabuçu observada nessa pesquisa indica ser a área um sítio de invernada, reforçando sua importância para a conservação das espécies migratórias que utilizam o local.

Every year, thousands of limicola and migratory birds winter on the South American coast, between September and April, where they acquire body mass and undergo moulting before returning to their reproduction sites. Qualitative and quantitative studies were performed in the Piaçabuçu Protection Area located in the state of Alagoas, Brazil, by direct counting, aiming to follow upon the birds' seasonal migration. Five species of Charadriidae family were recorded: Vanellus chilensis (Wagler, 1827); Pluvialis squatarola (Linnaeus, 1758); Charadrius semipalmatus Bonaparte, 1825; Charadrius collaris Vieillot, 1818 and Charadrius wilsonia (Ord, 1814), and five of the Scolopacidae family: Arenaria interpres (Linnaeus, 1758); Actitis macularius (Linnaeus, 1766); Catoptrophorus semipalmatus (Gmelin, 1789); Calidris pusilla (Linnaeus, 1766) and Calidris alba (Pallas, 1764). Pluvialis squatarola, Charadrius semipalmatus, Charadrius collaris, Arenaria interpres, Calidris pusilla and Calidris alba were considered constant (present in over 50% of observation time). Charadrius semipalmatus and Calidris alba showed highest level of frequency during November and December and March and September, respectively. Spearman correlation shows a strong dependency on migration of this species. The birds' loyalty to the Piaçabuçu area seen in this research show that this is a preferred site for wintering thus reinforcing its importance for the conservation of the migratory species that utilize the site.

The quantitative encephalic composition and cerebral indices of Vanellus c. chilensis (southern lapwing ) were analyzed. The percentual volumes and cerebral indices for the whole encephalon and for seven components were calculated as well as relevous nuclei of the trigeminal, visual and acoustic pathways. The component of greater relative volume is the telencephalon. The neostriatum is the most developed encephalic structure. Developing of bulbus olfactorius, striatum, tectum opticum and relevous nuclei of visual and trigeminal pathways are according with the carnivorous diet of Vanellus c. chilensis. The relative size of Wulst and relevous nuclei of acoustic pathway appears associated with the complex tactics used by this species in the defense of nest. Cerebral indices of all the analyzed structures suggest that Vanellus c. chilensis is a progresive bird

Se analizó la composición cuantitativa encefálica y se estimaron índices cerebrales en Vanellus c. chilensis (tero o queltehue). Se estimó el volumen porcentual e índices cerebrales del encéfalo total y de siete de sus componentes, como así también los núcleos de relevo de las vías trigeminal, visual y acústica. El telencéfalo es el componente de mayor volumen relativo, siendo el neoestriado la estructura telencefálica de tamaño superior. El desarrollo del estriado propiamente dicho, tecto óptico y los núcleos de relevo de las vías visual y trigeminal concuerdan con la dieta carnívora de Vanellus c. chilensis. El tamaño relativo del Wulst y de los núcleos de la vía acústica se asocia a las complicadas tácticas que utiliza esta especie en la defensa del nido. Los índices cerebrales de las estructuras encefálicas analizadas indican que Vanellus c. chilensis es un ave progresiva

The northern coast of Pernambuco State, Brazil, is an wintering area for shorebirds originally from north America, especially from the east. The first flocks arrive in September, staying till April, when they molts, change plumage, and acquire enough biomass to migrate back to the northern hemisfere. In order to calculate flight range mass and length of the wing of Charadrius semipalmatus Bonaparte, 1825, Calidris fuscicollis Vieillot, 1819, C. pusilla Linnaeus, 1766 and C. alba Pallas, 1764 was recorded. Traps were carried out in Coroa do Avião (7º40' S and 34º50'W) in the northern coast of the State of Pernambuco, between May 1992 and April 1995. The length of the wing was registered with the wing spread (from the insertion of the bone till the extremity of the longest primary remige). Individuals which were changing the tenth primary were not included in this measuring. Mass was taken in grarns, and flight range was calculated using the equations proposed for adult individuais. The individual with the highest flight range reached around 1831,87 km, and had been trapped and ringed in 14th April 1994, when had 61,5 g and wing measuring 12,9 cm, with intermediate plumage. The highest flight range reached by C. fuscicollis was around 1906,43 km. It had been trapped and ringed in the 3rd of May 1992, with weight of 50 g, and wing of 12,9 cm, and had reproduction plumage. The individual with the highest flight range reached 3545,77 km, had been trapped and ringed in 15th April 1994, weighted 44 g, wing measured 10 cm, and presented intermediate plumage. The specimen of C. alba which presented the highest flight range, of 82 g, wing of 13,4 cm, and had intennediate plumage.

Thirteen species of helminth parasites were recovered from six species of charadriid shorebirds (Aves: Charadriiformes) from Belize: the ruddy turnstone, Arenaria interpres, the snowy plover, Charadrius alexandrinus, the semipalmated plover, C. semipalmatus, the killdeer, C. vociferus, the white-rumped sandpiper, Calidris fuscicollis, and the black-bellied plover, Pluvialis squatarola. Cestode species were predominant (N = 8), followed by trematode species (N = 3) and acanthocephala (N = 2). The trematode, Paramaritremopsis solielangi infected four of the six species of hosts. The cestodes, Nadejdolepis litoralis and N. paranitidulans infected three and two host species respectively. Helminth parasite species were contagious (clumped) and not evenly distributed among hosts. Twelve of the 13 species were generalists. The one specialist Microphallus kinsellae was recovered from one C. fuscicollis. Three of the four types of feeding guilds were present and in approximately the same number. All but M. kinsellae have been reported from other species of hosts, mostly from Eurasia and North America.