Black-crowned Night Heron Nycticorax Research Articles

Population Trend of Colonially Nesting Heron Species in Greece

Heron colonies are dynamic components of wetlands. Therefore, their systematic monitoring is important for the management of both birds and wetlands. During the period 1988–2018, we counted breeding pairs of seven colonial breeding heron species at 65 colonies across 37 wetlands in Greece. We considered as annual variables of a population: (a) years since 1988, (b) Natura 2000 network inclusion, (c) protected area management authority overseeing, (d) wetland type (new or restored), and (e) new colonies (established after 2003). The Cattle Egret Bubulcus ibis and the Squacco Heron Ardeola ralloides had a positive breeding population trend. The Black-crowned Night Heron Nycticorax nycticorax, Little Egret Egretta garzetta, and Grey Heron Ardea cinerea had a negative trend, while the Purple Heron Ardea purpurea population was stable. The Great White Egret Ardea alba bred sporadically at only a few sites which precluded the evaluation of its population trend. The informative population variables differed among species, even of those at the same colony, which suggests trends are also affected by conditions at wintering grounds. The study highlights the need for the systematic monitoring of heron colonies and the protection of foraging/breeding areas in order to reverse the observed negative population trends.

ĐA DẠNG THÀNH PHẦN LOÀI CHIM Ở VƯỜN CHIM ĐÀO MỸ, HUYỆN LẠNG GIANG, TỈNH BẮC GIANG

The study on Dao My Stork Garden with an area of 3 hectares located in Tan Phuc village, Dao My commune, Lang Giang district, Bac Giang province during 2017 - 2018 has identified 32 bird species belonging to 29 genera, 18 families, 7 orders, including 21 resident species, 11 winter migratory species. There is one species listed in the Vietnam Red Data Book (2007) which is Anastomus oscitans. There are 6 species of water birds living and colony nesting in the stork garden: Little Egret (Egretta garzetta), Chineses pond Heron (Ardeola bacchus), Egret Cattle (Bubulcus coromandus), Black-crowned Night Heron (Nycticorax nycticorax), Intermediate Egret (Egretta intermedia) and Asian Openbill (Anastomus oscitans). The water bird species with the highest number of population in breeding season is the Little Egret. There is a stratification of the habitat and nesting areas of water birds according to the vegetation in the stork garden. Birds mainly nest and live on eucalyptus and bamboo trees. Since this stork garden formed on the land is owned by the household, in order to preserve the stork garden for sustainablity, it is necessary to support from the local government and organizations to invest in the restoration of trees in the garden and protecting the stork garden from illegal bird hunting.

Impacts of Great Cormorant and Cattle Egret Nesting on Other Waterbirds in a Shared Breeding Site in Piedmont (NW Italy)

Some waterbird species are believed to have an impact on other waterbird species as they are able to usurp a limited habitat and destroy vegetation. In this study, we have analysed the nesting dynamics of five waterbird species: Grey Heron Ardea cinerea, Great Cormorant Phalacrocorax carbo, Little Egret Egretta garzetta, Black-crowned Night Heron Nycticorax nycticorax and Cattle Egret Bubulcus ibis, that had settled in a colony in the Royal Castle Park of Racconigi (Cuneo, NW Italy) over a 17-year period (2000 to 2017). The Great Cormorant and the Cattle Egret settled in the colony in 2008 and 2012, respectively. We analysed the relationships between the number of breeding pairs of the five species. In addition, we used the time series forecasting method to study the nesting dynamics and the impact of the new settlements on the pre-existing colony. The number of nests of the Great Cormorant and the Cattle Egret increased annually, and these species significantly affected the nesting trends of the other pre-existing species: Grey Heron, Black-crowned Night Heron and Little Egret. The Grey Heron mainly suffered from the occupation of its old nests by the Great Cormorant from 2008 to 2013. However, since 2014, the Grey Heron has been able to react, by displacing its breeding site to the tops of trees adjacent to the old heronry, and this has resulted in an even greater number of nests than before 2008. The Black-crowned Night Heron and the Little Egret suffered more from the settlement of the new species than the Grey Heron did, and started to suddenly or gradually abandon the breeding site. The colony has been modified profoundly by the settlement of the Great Cormorant and the Cattle Egret, and it is still subject to dynamics that could transform it in the coming years.

First Provincial Record of Black-crowned Night heron (Nycticorax nycticorax) in West Sumatra and the Summary of Its Sumatran Records

The Black-crowned Night heron (Nycticorax nycticorax) is a known visitor in Sumatra with more sighting records in the eastern side of the island. Meanwhile, on the west, it was historically recorded from only two offshore islands, namely Nias and Enggano. During the waterbird survey from early 2018 at Pasir Jambak Beach of Padang City in the coastline of West Sumatra, a Night heron was spotted among the colony of mixed egret species. This is the first record of its kind in the province of West Sumatra, although, previous records cover almost all provinces in Sumatra. The summary of the compiled records of this species indicates that it is probably a vagrant along the western coastline, while it visits more frequently on the eastern side.

Nocturnal Migration in the Tataka Area, Yushan National Park, Taiwan in Autumn 2014

Detecting different bird species requires different and appropriate surveying methods. We tested a new detection method for the Tataka Area in Yushan National Park, Taiwan, which is an important alpine stopover site for migratory land-birds. Numerous migrant species have previously been reported from this area during bird counts and banding operations. However, these traditional survey methods are incapable of detecting nocturnal migrants. Therefore, we applied acoustic monitoring devices to survey the flight calls of nocturnal migrants in the Tataka Area in order to identify the species and estimate their detection rate. We set up acoustic recorders at five recording stations twice a month during September, October and November, and once in December 2014. We identified 18 nocturnal migrant taxa from 801 hours of recordings. The Black-crowned Night Heron Nycticorax nycticorax was the most frequently recorded species, followed by thrushes (Turdus spp.) and the Brown Shrike Lanius cristatus. Passages of nocturnal migrants occurred during every hour of the night, but with a significantly higher detection rate during the period from 2000 to 2300. Detection rates also varied significantly among months and recording stations. Significantly higher detection rates were recorded in September and October than in November and December. The recording station on a ridge detected significantly fewer birds than the other four recording stations situated in or near valleys. This suggests that nocturnal migrants use lower-lying stream valleys in order to pass over mountain ridges at the lowest possible point. This study provides the first evidence to demonstrate that, besides landbird migrants, many shorebird species and even kingfishers migrate through alpine areas at night when they pass over Taiwan Island during autumn migration.

Breeding Phenology and Reproductive Success of Little Blue Herons (Egretta caerulea) in an Urban Mixed-Species Colony

As human populations continue to expand into suburban and rural areas, conflicts with wildlife are likely to increase. Many populations of long-legged wading birds (Family Ardeidae) face the challenge of human disturbance both at feeding sites and breeding colonies. Little Blue Herons (Egretta caerulea) are medium-sized wading birds that often join egrets and other herons in mixed-species breeding colonies. In June and July 2018, a random sample of Little Blue Heron nests located in an urban colony were monitored from incubation to fledging. The goals of this study were to (1) characterize adult nest-activity patterns over the course of the breeding cycle, and (2) document Little Blue Heron reproductive success in an urban colony and identify sources of human disturbance. Instantaneous samples with 5-min intervals were used to record adult activity during 50 h of observation at 24 nests. An additional 77 h of continuous observation at two different nests documented fine-scale activities and changes in nesting status. Observations made at random times during morning, midday, and evening periods yielded 636 nest-hours across all breeding stages. During incubation, attending parents mostly sat (63 %) or stood (23 %) in or near their nests, spent less time in nest maintenance (5 %) and self-maintenance (scratching, preening; 5 %), and seldom (< 1 %) left the nest unprotected. By the end of the breeding cycle, nests were unattended 69 % of the time. The 26 monitored nests fledged a total 39 chicks (1.4 ± 0.3 chicks/nest attempt). The 16 successful nests (61 % of all nests) fledged 2.4 ± 0.2 chicks. Known causes of nest failure included destruction or usurpation by Cattle Egrets (Bubulbus ibis) and predation by Black-crowned Night-herons (Nycticorax nycticorax). Sources of disturbance included dogs allowed in the colony, intentional loud noises, and human presence. We compare reproductive success at this urban colony to that in less disturbed colonies reported in the literature.

Distribution and abundance of marsh-nesting colonial waterbirds in Prairie Canada

Waterbird species face numerous threats and many are declining globally, but knowledge of distribution, abundance, and trend remains poor for many species. Five species of marsh-nesting colonial waterbirds are poorly monitored in Canada, and especially so in the core of their range in the Canadian Prairie Provinces (Alberta, Saskatchewan, and Manitoba). We summarized published and unpublished data on abundance and distribution of breeding colonies of Western Grebe (Aechmophorus occidentalis), Franklin's Gull (Leucophaeus pipixcan), Black Tern (Chlidonias niger), Forster's Tern (Sterna forsteri), and Black-crowned Night-Heron (Nycticorax nycticorax) in Alberta, Saskatchewan, and Manitoba. We also examined the degree of overlap in nesting phenology (egg dates) and summarized survey methods that have been used to monitor the species during the breeding season—information that may be useful for the development of a multispecies monitoring program. For all species, the largest number of records of breeding colonies occurred in Alberta, with records declining eastward through Saskatchewan and Manitoba. We identified a number of breeding colonies occurring outside of currently defined species ranges, especially for the poorly studied Forster's Tern. Of 137 waterbodies hosting a colony of at least one species over the past 10 yr, 57 (41.6%) hosted colonies of at least 2 species, and 3 (2.2%) hosted colonies of all 5 species. Species tended to be reasonably synchronous in their breeding phenology, but Franklin's Gulls and Black-crowned Night-Herons tended to initiate nesting slightly earlier than the other species. We conclude that a multispecies survey timed in late May or early June to count nests and/or incubating adults, using either ground-based or aerial surveys, would likely be the most appropriate for monitoring all species jointly in the Prairie Provinces. The approach we take to compiling data from multiple sources on species occurrence and breeding phenology may be applicable to others wishing to examine the feasibility of a multispecies monitoring plan.

Nesting Dynamics of Four Ardeid Species at Subregional Scales: Recovery Rates after Sudden Major Declines in Nest Abundance

The functional roles of nesting heron species (Ardeidae) as top predators in regional wetland landscapes may be sensitive to variation in nesting abundances at subregional scales corresponding to available habitat for nesting and foraging within individual wetland subsystems. This study investigates the dynamics of annual nesting abundances of four ardeid species within 10 major wetland subsystems of the San Francisco Bay Area, California, USA, during 1991–2010. Interrupted time series analysis was used to measure impact and recovery rates related to sudden major declines in nesting abundance below selected thresholds of annual change. Year-to-year persistence of initial impacts was above 78% for Great Blue Herons (Ardea herodias) and Great Egrets (A. alba). Snowy Egrets (Egretta thula) recovered more quickly, with 63–66% annual carryover of initial impacts. The time required for 95% recovery averaged 18.8 years for Great Blue Heron, 13.0 years for Great Egret, 7.2 years for Snowy Egret, and 14.5 years for Black-crowned Night-Heron (Nycticorax nycticorax). Most of the major subregional declines in nest abundance were associated with impacts at a single colony site. The results highlight the significant effects of sudden major declines in nesting abundance on the status of ardeids within individual wetland systems across a larger regional wetland landscape.

Interspecific Broods at Two Heronries in Iran

Abstract. Four cases of interspecific mixed broods between Little Egrets (Egretta garzetta; n = 175), Cattle Egrets (Bubulcus ibis; n = 125), Squacco Herons (Ardeola ralloides; n = 25) and Black-crowned Night-Herons (Nycticorax nycticorax; n = 199) were recorded from 7 April to 16 August 2016 at two colonies in Iran. The rare occurrence of mixed broods and the low survival of the parasite chicks suggest that brood parasitism is not adaptive in the Ardeidae.

Morphometric Differences Between Sexes of Two Subspecies of Black-crowned Night-Heron (Nycticorax nycticorax) Using Discriminant Function Analysis

The objective of this study was to develop tools for distinguishing between sexes of the two Black-crowned Night-Heron (Nycticorax nycticorax) subspecies (N. n. obscurus and N. n. hoactli) using discriminant function analysis. Significant differences were found in length of the culmen, length of the bill from the gape, and length of the wing chord between the sexes of each subspecies, with males being larger than females. The resulting discriminant functions were able to differentiate between the sexes of each studied subspecies and between subspecies after determining the sex of the individuals (with a correct classification of 77.8% for females and 97.8% for males). In females, all morphometrics were greater for N. n. obscurus than N. n. hoactli; this was also the case for males, except for bill width, which was greater in N. n. hoactli. Wing chord length was the most useful measurement for constructing the discriminant functions. External morphometrics are a valuable tool not only for discriminating between N. n. hoactli and N. n. obscurus but also for sexing these subspecies.

Dietary Segregation of Four Ardeid Species Breeding in Anzali International Wetland, Northern Iran

Abstract. The nestling diets of four heron species breeding on a small forestry islet in Anzali, Iran, were investigated to determine the dietary segregation among sympatric breeders. Regurgitated samples from Black-crowned Night-Herons (Nycticorax nycticorax), Little Egrets (Egretta garzetta), Cattle Egrets (Bubulcus ibis) and Squacco Herons (Ardeola ralloides) were collected during the breeding season from 23 May to 16 August 2016. A total of 1,606 prey items were identified representing 39 prey categories from nine different classes. Differences were detected among these four ardeid species for the percentage of each prey category. Fish dominated the regurgitates of the Blackcrowned Night-Heron (67%; n = 43 samples), Little Egret (45%; n = 33 samples) and Squacco Heron (53%; n = 10 samples), whereas arachnids and insects combined (53% and 40%, respectively, based on total number of individuals) and insects (61.9% based on weight) were the most common prey items for the Cattle Egret. Although fish items...

Nest position, breeding success and diet of the Black-crowned Night Heron, Nycticorax nycticorax in the Anzali Wetland, Northern Iran (Aves: Ardeidae)

Breeding ecology of the Black-crowned Night Heron (Nycticorax nycticorax) was studied in a mono-specific colony in the Anzali wetland, Northern Iran during the breeding season of 2016. The breeding period lasted from mid-May to late July. The average clutch size was 3.1±0.6 eggs and the breeding success 77.6%. No significant differences were found between nests built on trunks and those built on branches of trees. The clutch size and breeding success appeared to be independent of the structural variables of the nesting site (diameter of trees, height from the ground, height of nests from the canopy, nest number per tree, location of nests on trunks and branches). No significant difference was found between the timing of the start of incubation and the height of nests above the ground. The average vertical and horizontal distances between nests was one metre. Fish, particularly Carassius gibelio, dominated the diet of the nestlings.

Observations of Indirect Filial Cannibalism in Response to Nest Failure of Black-crowned Night-Herons (Nycticorax nycticorax)

ABSTRACT During 2011, four separate instances of indirect filial cannibalism, whereby adults consumed their young that died from unknown causes, were observed using video-monitoring techniques in a nesting colony of Black-crowned Night-Herons (Nycticorax nycticorax) on Alcatraz Island. Though they were not observed actively killing their young, in all four observations adult Black-crowned Night-Herons consumed their young following death (i.e., indirect filial cannibalism). We could not determine cause of chick mortality, but parental neglect was likely a contributing factor in at least two instances. Indirect filial cannibalism is not commonly documented among birds, and understanding how cannibalism contributes to nest failure can help researchers better understand factors that limit nesting populations.

Factors Affecting Foraging Microhabitat Selection by Wading Birds at an Artificial Weir

Abstract. To better understand how wading birds select among microhabitats that show spatial heterogeneity, a concrete weir located at the terminus of the Little Arkansas River in Wichita, Kansas, USA, was divided into patches based on water depth. Black-crowned Night-Herons (Nycticorax nycticorax; n = 396), Great Egrets (Ardea alba; n = 54), Snowy Egrets (Egretta thula; n = 36), and Great Blue Herons (Adrea herodias; n = 30) were observed for 60 hr from 10 June-29 July 2015. The total number of individuals was recorded, as was species-specific patch use, feeding activity, and aggression. Only time of day and water depth predicted the number of birds at the weir (R 2 = 0.52). Wading bird species differed in capture efficiency, mean prey size, and patch use. Great Blue Herons and Black-crowned Night-Herons mainly captured larger fish below the weir, Snowy Egrets captured mostly smaller fish along the weir edges, and Great Egrets captured both large and small fish. Mean fish length differed by patch and ran...

Swimming Black-Crowned Night-Herons (Nycticorax nycticorax) Kleptoparasitize American Coots (Fulica americana)

Abstract I observed black-crowned night-herons (Nycticorax nycticorax) swimming and kleptoparasitizing American coots (Fulica americana) at an artificial lake in Pinal County, Arizona. This appears to be the first record of interspecific kleptoparasitism by a swimming ardeid.

Avian Predators Target Nocturnal Runs of the Beach-Spawning Marine Fish, California Grunion,Leuresthes tenuis(Atherinopsidae)

Tidal cycles are important cues for many marine and near-shore animals. Birds that typically feed at the water's edge during daytime low tides are rarely present on beaches at night. However, we found that several species of diurnal birds reliably attended and preyed upon the nocturnal spawning runs of a marine fish, Leuresthes tenuis, the California Grunion (Teleostei: Atheriopsidae) on the shores of Malibu Lagoon State Beach (MLSB), Los Angeles County, California, USA. Avian hunters of California Grunion included Black-crowned Night Heron Nycticorax nycticorax, Great Blue Heron Ardea herodias, Snowy Egret Egretta thula, and Western Gull Larus occidentalis. Spawning runs of California Grunion are synchronized by tides within a narrow window of time, two hours following the semilunar high tides of full and new moons. These silverside fish aggregate en masse predictably, and further increase their vulnerability by fully emerging from the water while spawning. This allows the birds to capture California Grunion terrestrially. On nights when spawning runs of California Grunion could potentially occur, birds were present on MLSB, often before the fish began to run onto shore. Number of birds was high for the nights of likely runs whether after full or new moons, whether or not the fish appeared, but not on other nights. We suggest that birds rely on tidal cues to anticipate spawning runs of California Grunion, not the amount of moonlight or the actual presence of fish on shore. Shorebirds were more likely to forage at night at sites close to their upland roosting and nesting areas than at sites with less upland habitat. Observers on nearby Will Rogers State Beach and Topanga State Beach saw comparable spawning runs of California Grunion but reported significantly fewer avian predators. At MLSB, when tide conditions were right, avian predators appeared on the beach with even greater predictability than did their potential prey.

Comparison of trace element concentrations in grey heron and black-crowned night heron chicks.

Cadmium (Cd), lead (Pb), manganese (Mn), zinc (Zn), and iron (Fe) concentrations were measured in the prey and liver of grey heron (Ardea cinerea) and black-crowned night heron (Nycticorax nycticorax) chicks (24-26 days after hatching) at the Pyeongtaek colony, Korea in 2001 (n = 10, respectively) and 2008 (n = 11 and n = 10). Cadmium and Pb concentrations in livers of grey heron (Cd geomean 0.06, Pb 3.90 μg/g dw) and black-crowned night heron (Cd 0.20, Pb 4.24 μg/g dw) chicks were increased with diet concentrations of grey heron (Cd 0.18, Pb 1.76 μg/g dw) and black-crowned night heron (Cd 0.20, Pb 3.96 μg/g dw) chicks. Cadmium and Pb concentrations in prey items of grey heron and black-crowned night heron chicks were a good predictor of chick liver concentrations. Cadmium concentrations in livers of both heron species collected at the Pyeongtaek heronry were relatively low and within the background level (<3 μg/g dw) for birds. Five of 20 (25.0%) grey heron and 4 of 18 (22.2%) black-crowned night heron chicks were higher than the background level for lead (>6 μg/g dw). Prey Cd and Pb concentrations were within the range of other heron and egret studies. Manganese, Zn, and Fe concentrations in grey heron and black-crowned night heron chicks were within the background or normal physiological levels reported earlier in other birds including herons and egrets.

Concentrations of Cd, Pb, Mn and Zn in feathers and diet in heron chicks in Korea.

The feathers and diet items of grey heron (Ardea cinerea) and black-crowned night-heron (Nycticorax nycticorax) chicks were collected at the Pyeongtaek colony, Korea in 2002 and 2008, and Cd, Pb, Mn and Zn concentrations were measured. Cd and Zn concentrations were higher in both species in 2008 than 2002 and were higher in grey herons than black-crowned night-herons in 2002. In 2008, Cd concentrations were higher in black-crowned night-herons than grey herons; Zn concentrations did not differ between species. Pb and Mn concentrations did not differ between species; however, there were yearly differences. Cd, Pb and Zn concentrations of feathers and diet were significantly correlated when species and years were combined. However, the predictive power of these relationships was limited because of species and yearly differences. All heron chicks had concentrations of Cd (<2 μg/g dw) and Pb (<4 μg/g dw) consistent with background concentrations for wild birds. Mn and Zn concentrations were within the range reported for other heron and egret species.

SEROSURVEILLANCE OF AVIAN INFLUENZA VIRUS SUBTYPE H5N1 WITH HAEMAGGLUTINATION-INHIBITION ON WILD AQUATIC BIRDS IN PULAU DUA SERANG NATURAL RESERVES, BANTEN PROVINCE

Further detailed research is required to obtain deeper information on the role of wild birds on the distribution of Avian influenza in Asia. A research has been carried out on February–June 2007 focused on blood sampling (serosurveillance) of wild birds in Pulau Dua Nature Reserves (CAPD), Serang, Banten. The research is aimed to investigate the infection of AI virus sub-tye H5N1 on the studied wild birds. The blood samples were taken from studied aquatic birds, followed by HI (haemagglutination-inhibition) test. A total of 183 samples represent 7 water bird species were taken i.e Cattle egret Bubulcus ibis, Javan pond-heron Ardeola speciosa, Little egret Egretta garzetta, Intermediate egret Egretta intermedia, Black-crowned night heron Nycticorax nycticorax, Great egret Casmerodius albus and Grey heron Ardea cinerea. The result revealed that 41 (23.27%) samples showed the present of AIV antibodies serotype H5N1 which is identified as positive. Data showed 5 positive-test species, including B. ibis (29.27%), E. garzetta (29.27%), E. intermedia (4.88%), Ardeola speciosa (7.32%), and N. nycticorax (29.27%). A total of 41.46% were infected adult individual, whereas 58.54% were juveniles.

Monitoring of Heavy Metal Contamination Using Tissues of Two Ardeids Chicks, Korea

This study presents concentrations of iron, zinc, manganese, lead and cadmium in livers and kidneys of Little Egret Egretta garzetta (n = 10) and Black-crowned Night-Heron Nycticorax nycticorax (n = 10) chicks from Pyeongtaek, Gyeonggi-do, Korea. Essential element concentrations such as iron, zinc and manganese did not differ between both species chicks in livers and kidneys, but lead and cadmium concentrations were significantly greater in both tissues of Little Egret chicks (lead 2.78 +/- 4.06 microg/g wet weight, cadmium 10.3 +/- 12.8 kg/g wet weight) than in those of Black-crowned Night-Heron chicks (lead 0.92 +/- 0.73 microg/g wet weight, cadmium 1.00 +/- 1.00 kg/g wet weight). Lead and cadmium concentrations in livers of Black-crowned Night-Heron chicks were highly related to sediment and/or prey concentrations of their foraging sites in Korean studies. It shows that lead and cadmium concentrations in livers of heron chicks can reflect those of surrounding environment of breeding sites. In this study, cadmium concentrations were higher in kidneys than in livers and it's not recent high-level exposure but chronic background exposure to cadmium contamination around breeding site. Therefore, we suggest that cadmium concentrations in livers and kidneys can be used as a bioindicator of acute and/or chronic local contamination.