Notes on Young of Plumed Tree-Duck

The Llanos is a significant waterbird site in the Western Hemisphere, but abundance and distribution of waterbirds across this vast region are poorly known, which hampers conservation initiatives. We used point counts along road routes in the Llanos region of Venezuela to examine abundance and distribution of waterbirds during 2000–2002 within five ecoregions across the Llanos. We detected 69 species of waterbirds and recorded 283,566 individuals, of which 10 species accounted for 80% of our observations. Wading birds (Ciconiiformes) represented the largest guild both in numbers of species (26) and individuals (55%), followed by waterfowl (26%), and shorebirds (11%). Five species comprised 62% of all individuals: Cattle Egret (Bubulcus ibis), White-faced Whistling Duck (Dendrocygna viduata), Black-bellied Whistling Duck (D. autumnalis), Great Egret (Ardea alba), and Wattled Jacana (Jacana jacana). Wading birds were particularly ubiquitous with at least 21 of 26 species recorded in each of the ecoregions. Species richness (66), proportion of waterbirds detected (54%), and mean number of birds per route (1,459) were highest in the Banco-Bajio-Estero savanna ecoregion. Our study provides the most comprehensive data set available on waterbirds in the Llanos of Venezuela and highlights regions of special conservation concern.

The Water Fowl of the World By Jean Delacour; illustrated by Peter Scott. Vol. 1: The Magpie Goose, Whistling Ducks, Swans and Geese, Sheldgeese and Shelducks. Pp. 284 + 16 plates. 105s. Vol. 2: The Dabbling Ducks. Pp. 232 + 24 plates. 126s. net. (London: Country Life, Ltd., 1954 and 1956.)

The Llanos is a significant waterbird site in the Western Hemisphere, but abundance and distribution of waterbirds across this vast region are poorly known, which hampers conservation initiatives. We used point counts along road routes in the Llanos region of Venezuela to examine abundance and distribution of waterbirds during 2000–2002 within five ecoregions across the Llanos. We detected 69 species of waterbirds and recorded 283,566 individuals, of which 10 species accounted for 80% of our observations. Wading birds (Ciconiiformes) represented the largest guild both in numbers of species (26) and individuals (55%), followed by waterfowl (26%), and shorebirds (11%). Five species comprised 62% of all individuals: Cattle Egret (Bubulcus ibis), White-faced Whistling Duck (Dendrocygna viduata), Black-bellied Whistling Duck (D. autumnalis), Great Egret (Ardea alba), and Wattled Jacana (Jacana jacana). Wading birds were particularly ubiquitous with at least 21 of 26 species recorded in each of the ecoregions. Species richness (66), proportion of waterbirds detected (54%), and mean number of birds per route (1,459) were highest in the Banco-Bajio-Estero savanna ecoregion. Our study provides the most comprehensive data set available on waterbirds in the Llanos of Venezuela and highlights regions of special conservation concern.

Lesser Whistling Ducks (LWD) (Dendrocygna javanica) mostly occur in flocks and inhabit lakes, ponds and marshes within freshwater wetlands. They feed mainly on plants taken from water (seed, shoots, tuber and leaves), vertebrates (fishes) and invertebrates (mollusks and worms). In this study, habitat preference of LWD in five selected wetlands in Colombo Ramsar Wetland City (CRWC); Beddagana Wetland Park (BWP), Diyasaru Park (DP), Heen Ela Marsh (HEM), Thalangama Marsh (TM) and Kimbulawala Wetland (KW) was studied from May 2021 to April 2022 as wetlands in urban areas act as the last resort for many resident and migratory bird species and play a major role in the assemblage and conservation of water birds. Habitats present in the selected wetlands were categorized as open water body, floating vegetation, trees, grassland, paddy field, shrubs, bare land. Percentage cover of each habitat type at each sampling site were estimated using quadrat method. LWD were surveyed using line transects of 100m in length, laid in each selected study site to cover representative habitats and observations were made up to 30m towards either side of each transect. Sampling was done in three time slots of the day, morning, mid-day and evening. Floating vegetation, open water body and grassland were the preferred habitat types of D. javanica in BWP, DP, HEM and TM. LWD were not recorded in KW. Floating vegetation (54.97%) was the most preferred habitat by LWD in each study site followed by open water body (24.70%) and grassland (15.82%) habitat types. Eicchornia crassipes (Common water hyacinth) and Salvinia molesta (Giant salvinia) were their most preferred floating vegetation type. Higher abundance of LWD was recorded in TM (83.22%) followed by DP (9.17%), BWP (4.16%) and HEM (3.45%). TM which had higher abundance of LWD had higher floating vegetation coverage (28%) and was rich with E. crassipes and S. molesta. Present study revealed that, LWD mostly used E. crassipes and S. molesta as their main foraging and resting sites. Management of invasive alien species have been undertaken in Colombo wetlands and as E. crassipes and S. molesta are alien species they are currently being removed. Therefore, outright removal of E. crassipes and S. molesta may not be suitable and a monitored removal program that will conserve this habitat type should be implemented in order to conserve the habitats preferred by LWD in CRWC. 
 Keywords: Lesser whistling ducks, Wetlands, Habitat preference

Waterbirds play essential ecological function contributing to maintenance of species diversity, pest control, seed dispersal, and vectors for invertebrates. Approximately one-third of the waterbird assemblage inhabits wetland environments. However, waterbirds and their habitats are threatened by human activities capable of disrupting ecosystem. This study was conducted in Usangu Wetland Important Bird Areas to investigate the abundance, distribution, and population trends of wild avian species. Bird counting survey and questionnaire were conducted from to elicit information about abundance and distribution, and bird population trend respectively between March and May, 2022. Bird counts were conducted using 2.5 km line transects at three sites. Each site had six transect replicates to estimate relative abundance and distribution. Structured and key informant interviews were used to elicit trends of bird populations over the past 20 years and their influencing factors. Data were analyzed using R-studio version 4.0.3. Furthermore, content analysis was employed to scrutinize perceived population trends. The study cataloged a total of 34 distinct species of waterbirds. The most prevalent species included lesser moorhen (Gallinula angulata) 47.56%, Fulvous Whistling Duck (Dendrocygna bicolor) 12.01%, and Glossy ibis (Plegadis falcinellus) 10.15%. The distribution patterns of waterbirds were determined by habitat type, geographical location, farm characteristics, and the specific rice scheme type, with a greater concentration in rice plantations and outgrowers rice schemes. Local accounts underscored a declining trend in waterbird populations over past 20 years due to illegal hunting and habitat conversion. Usangu wetland has a higher abundance of water birds with disproportionate distribution bias in rice farms. In spite of rice farms suitably holding a high assemblage of water birds, its sustainability is subject to owners' decision, vegetation cover changes after rice harvest characterized by illegal hunting.

In Argentina, the Ringed Teal (Callonetta leucophrys) and the Black-bellied Whistling Duck (Dendrocygna autumnalis) are common but scarcely studied species. To characterize the seasonal distribution of nesting, the number of eggs per nests, and the eggs of these duck species, nest boxes were surveyed during six reproductive seasons in several wetlands from southwestern Corrientes province. From all these surveys, 389 nesting events were recorded for C. leucophrys and 979 nesting events for D. autumnalis. The nesting peak for C. leucophrys occurred in October-November, whereas the peak for D. autumnalis was in January-February. The clutch size was smaller for C. leucophrys than for D. autumnalis (median: 10 and 14 eggs, respectively). The inside of the nest boxes occupied by C. leucophrys were covered with down, whereas D. autumnalis did not add any extra material to cover it. Eleven females of C. leucophrys were recaptured along various reproductive seasons, at the same wetlands, and even at the same nests that they had been banded. Recaptured females of D. autumnalis did not return to the same nest box. The eggs of C. leucophrys were smaller than those of D. autumnalis (length: 46.19 ± 1.79 mm vs. 50.76 ± 1.95 mm; width: 34.04 ± 1.14 mm vs. 37.65 ± 1.19 mm; weight: 27.68 ± 2.89 g vs. 38.65 ± 3.73 g, respectively). These results highlight the utility of nest boxes to increase our knowledge about the reproductive biology of duck species that nest in cavities.

This study was carried out to examine avian species richness and diversity at the Dschang Municipal Lake and to determine the effects of ecotourism infrastructural development on the avifauna distribution. The habitat around the lake was stratified into the undeveloped eastern part with natural/farm bush vegetation cover and the infrastructural developed western part with buildings and carpet grass lawns. A total of six transects each of 400 m length were established for bird census by vision and through their calls/songs. Sixty one (61) bird species were observed at the Dschang Municipal Lake amongst which seven were Palearctic migrants, 10 Inter-African migrants and 44 Residents. Two rare and occasional species were observed; the Fulvous Whistling Duck (Dendrocygna bicolor) and Intermediate Egret (Egretta intermedia). No significant seasonal variation was observed for bird species richness and diversity as our survey seasons were not very distinct. Similarly, species richness did not vary significantly between the undeveloped and the ecotourism infrastructural developed parts but varied in diversity index. Diversity index for water birds was greater in the undeveloped part of the lake while for terrestrial birds it was the reverse. Overall, this landscape heterogeneity at the Dschang Municipal Lake with developed and undeveloped parts provide a variety of habitat types for the diversity of bird species recorded and should be properly managed and conserved from a landscape approach. Key words: Bird, wetlands, dam, seasonal variations,habitat variations.

A non-invasive study on Dendrocygna viduata was carried out at a selected water body in Osogbo, Osun State, Nigeria to investigate daily, monthly and seasonal patterns in key diurnal activities frequencies to quantify diurnal activity budgets, visibility, and habitat preference. Observations of species activities were evaluated, during morning and afternoon, and twenty six (26) species of Dendrocygna viduata was recorded. Focal animal sampling method was used to select one individual at a time for observation and collection of activity data. Overlapping in collection of data was avoided carefully. Eight key diurnal activities of White-faced Whistling Duck were selected for the study. Normality test for all response variables was conducted using Shapiro-Wilk test for normality, and results was considered significant at 5% level. There was no significant difference in the mean frequency between the different activities, such as flying, resting, bathing and preening. There was a significant difference between the species activities and season and month. During the wet season, the highest mean frequency of activities was observed in April, while in the dry season the highest mean frequency of activities was observed in December. Although, the mean frequency of activities was slightly higher in the afternoon than morning, but it was not significant and does not determine the frequency of activities employed by the White-faced whistling duck. More research is needed to assess this species in early morning or late evening to achieve greatest accuracy and time-efficiency, creating desirable habitat in the vicinity by modifying the dam to encourage aquatic plant development.

Las diferentes anormalidades en el plumaje son resultado de múltiples factores ambientales y genéticos. En México se han reportado aberraciones en el plumaje de las aves, no obstante, todas se han clasificado como leucísticas (color blanco del plumaje debido a un gen recesivo). Otros tipos de aberraciones en el plumaje se han identificado, tales como el encanecimiento progresivo, el melanismo o las mutaciones, como la marrón, aún no reportadas para México. Durante trabajo de campo con aves en el estado de Nayarit, observamos individuos de seis especies de aves con plumajes anormales que caracterizamos como no leucísticos. Determinamos encanecimiento progresivo en pijije ala blanca (Dendrocygna autumnalis), zopilote aura (Cathartes aura), playero menor (Calidris minutilla) y golondrina tijereta (Hirundo rustica); plumaje marrón en avoceta americana (Recurvirostra americana) y plumaje ino en fragata magnífica (Fregata magnificens). El plumaje marrón y el ino involucran factores genéticos. El encanecimiento progresivo fue la aberración observada más frecuente, y diversos factores, que pueden ser genéticos, están involucrados en su expresión. Estas aberraciones, sin embargo, no habían sido previamente reportadas para aves en México.

Rice fields in southwestern Louisiana provide breeding habitat for several waterbird species; however, little is known about nest density, nest survival and the importance of landscape context of rice fields in determining breeding activity. In 2004, 42 rice fields were searched for nests, and 40 were searched in 2005. Land uses surrounding rice fields, including irrigation canals, trees, crawfish ponds, rice, fallow and soybean fields, were examined to determine influence on nest density and survival. Nest densities were 13.5–16.0 nests/km2 for Purple Gallinules (Porphyrio maitinica), 3.0–13.7 nests/km2 for Fulvous Whistling Ducks (Dendrocygna bicoloi), 2.6–2.8 nests/km2 for Common Moorhens (Gallinula chloropus), 0.3–0.92 nests/km2 for Least Bitterns (Ixobiychus exilisi) and 0–0.6 nests/km2 for Mottled Ducks (Anas fulvigula). Nest survival was 52–79% for Purple Gallinules and 39–43% for Fulvous Whistling Ducks. Apparent nest success of Common Moorhens was 73–75%, 83% for Least Bitterns and 33% for Mottled Ducks. Purple Gallinule and Common Moorhen nest densities were highest in fields with a larger proportion of irrigation canals surrounding rice fields. Purple Gallinule nest densities were greater in fields devoid of trees and landscapes dominated by rice fields and pasture, rather than landscapes containing soybean fields and residential areas. Fulvous Whistling Duck nest densities were higher in agriculturally-dominated landscapes with few trees.

The Hadejia-Nguru wetlands in north-east Nigeria are of international importance for resident and migratory Anatidae but the construction of large dams upstream seriously threatens their continued existence. An analysis of waterfowl census data collected over the period 1988 to 1998 inclusive demonstrated that the extent of flooding had no effect on the species richness of waterfowl but had a significant impact on total numbers. White-faced Whistling Duck Dendrocygna viduata and Garganey Anas querquedula in particular respond to changes in flood extent. The present practice of releasing water from upstream reservoirs should therefore be continued.

Black-Bellied and Fulvous Tree Duck, in Illinois

Visual sensitivity in the black-bellied tree duck (Dendrocygna autumnalis), a crepuscular species.

that most of one side of the head had been eaten away by some predaceous animal, the specimen was in good condition, though the presence of several shot holes in the body indicated the probable cause of the bird's death.Mr. Clarence Cottam's record of the third North Carolina specimen, taken on Lake Mattamuskeet last winter (Auk, July, 1935) would place ours as the fourth record, accompanied by a specimen, from this state.A Glaucous Gull (Larus hyperboreus) was taken in the harbor off Southport, N. C., on March 22, 1935, and reached the Museum, in the flesh, on the following day.It proved to be a female in second year immature plumage.This Gull had been observed off the Southport water-front for a week or more previous to its capture, and it would appear to be the third record, accompanied by a specimen, from North Carolina, one of the other two having been taken in the same immediate locality.As I am unable to find any record of this first Southport specimen in 'The Auk,' the following data are submitted: In a letter to my brother, C. S.

(Uploaded by Plazi from the Biodiversity Heritage Library) No abstract provided.