Evidence of Low-Habitat Contamination Using Feathers of Three Heron Species as a Biomonitor of Inorganic Elemental Pollution.

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.

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.

Habitat selection, foraging behaviour and prey items of five species of herons were studied at an estuary in Chiba Prefecture, central Japan. The two largest species, the Grey Heron Ardea cinerea and the Great White Egret Egretta alba modesta fed mainly on the tidal flat and in the river. The three smaller species, the Intermediate Egret E.intermedia, the Little Egret E.garzetta and the Cattle Egret Bubulcus ibis fed mainly on farmland. The Great White Egret and Little Egret were habitat generalists using all types of habitat, whilst the three other species seemed to be habitat specialists. Grey Herons fed only in large bodies of water; Cattle Egrets were highly terrestrial feeders; Intermediate Egrets preferred farmlands or wet habitats but avoided both large bodies of water and dry habitats. The primary foraging behaviour of Grey Herons was Standing by which method they captured large prey. Great White Egrets adopted a Walking Slowly method as well as Standing, and they took significantly smaller prey than Grey Herons. Intermediate Egrets adopted mainly Walking Slowly, Standing and slow foraging behaviours, in contrast to Little Egrets that used Walking Quickly and very active foraging behaviours. Cattle Egrets foraged mainly by Walking Slowly, but also adopted active foraging behaviours. In their feeding ecology, the Grey Heron, Intermediate Egret and Little Egret in Japan seemed to be, respectively, ecological counterparts to the Great Blue Heron A.herodias, Little Blue Heron E. caerulea and Snowy Egret E.thula in North America. Recent population declines of the Intermediate Egret may be related to deterioration of the farmland habitats upon which this species depends.

La valeur ornithologique des zones humides de l'est Algerien

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.

-Agricultural development has been considered a major factor influencing changes in species, species' distributions and abundances. We examine the effects of this process on colonial ardeid populations in a Mediterranean ecosystem in south-western Spain, where an ambitious irrigation plan has lead to structural homogeneity of a large area. During this process Cattle Egret (Bubulcus ibis) and Grey Heron (Ardea cinerea) populations have increased in the area. The Cattle Egret population was strongly associated with irrigated land while the Grey Heron population increased in the general area as a consequence of the recent colonization of it, but avoided local areas with extensive irrigated lands. Little Egret (Egretta garzetta) and Black-crowned Night-heron (Nycticorax nycticorax) populations were independent of the changes in agricultural practices. Received 10 September 1997, revised 6 October 1998, accepted 15 May 1999.

Summary Tomlinson, D. N. S. 1979. Interspecific relations in a mixed heronry. Ostrich 50:193-198. Fortnightly censuses were conducted at a heronry in Lake Kyle, Rhodesia, from January toMay1974, and while certain species (Reed Cormorant Phalacrocorax africanus, Grey Heron Ardea cinerea and Black headed Heron Ardea melanocephala) continued to arrive in small parties throughout the breeding season, others (Great White Egret Egretta aha, Cattle Egret Bubulcus ibis and Night Heron Nycticorax nycticorax) exhibited a high degree of breeding synchrony. P. africanus showed a significant nesting association with A. cinerea and A. melanocephala, while N. nycticorax was associated with C. albus. B. ibis did not show any significant nesting association with the other species.

Patterns of association between algae, fishes and grey herons Ardea cinerea in the rocky littoral zone of a Scottish sea loch

Rice fields and waterbirds are an example of a synergy that can occur between agriculture and conservation. This connection is especially relevant during the farming period, when nesting waterbirds need to obtain resources to cover their energy requirements and those of their chicks in rice fields. However, new farming techniques may potentially put fulfilling this role at risk. Studies on how species use rice fields to feed during this critical period are essential to understand waterbird population dynamics and to optimize conservation measures. At present, several species of colonial birds in l’Albufera de València (Spain) that depend on trophic resources available in rice fields have decling populations and decreases in productivity. We therefore assessed trophic niche segregation in the diet of chicks of a waterbird community composed of seven species through stable isotope analyses of carbon (δ13C) and nitrogen (δ15N) obtained from chick blood and tissue samples of potential prey. According to trophic niche widths, chicks of Black‐headed GullChroicocephalus ridibundusand Gull‐billed TernGelochelidon niloticashowed a similar diet, although Gull‐billed Tern had a major trophic specialization. The Western Cattle EgretBubulcus ibisfed its chicks in a wider range of different habitats, with organisms located at the base of the food chain and with a greater importance of terrestrial prey than other species. Conversely, the Glossy IbisPlegadis falcinellushad a more differentiated diet, mostly in freshwater habitats and mainly consuming odonates. Grey HeronArdea cinerea, Little EgretEgretta garzettaand Squacco HeronArdeola ralloidesshowed overlap between their niches, largely explained by the presence and abundance of cyprinid fish and odonates in their diets. Our results suggest a less important role than expected of Red‐swamp CrayfishProcambarus clarkii, and a more important role of odonates despite being a less energy‐rich prey. In conclusion, the diet of generalistic species of waterbirds in this study suggests that their trophic niches can overlap when relative prey abundance is high.

This study measured concentrations of iron, manganese, zinc, copper, lead, and cadmium in environmental substrates (water and sediment) as well as in the diet and feathers of Black-crowned Night Heron Nycticorax nycticorax and Grey Heron Ardea cinerea chicks from Pyeongtaek heronry, Gyeonggi-do, Korea. Zinc and cadmium concentrations in sediment were relatively high, but lead was low. In the diet, only copper concentrations were higher in Black-crowned Night Herons than in Grey Herons. Cadmium concentrations in the diet of two heron species from a Pyeongtaek heron colony were also higher than reported in other studies. In feathers, iron, copper, and lead concentrations were significantly different between heron species. Iron and copper concentrations were higher in Black-crowned Night Heron chicks than in Grey Heron chicks, but lead concentrations were not. Therefore, with the exception of lead, heavy metal concentrations in feathers were not related to concentrations in the diet. Zinc, iron, and lead concentrations in heron feathers were within the ranges reported by other heron studies, but manganese, copper, and cadmium were much higher. Lead and cadmium concentrations in feathers of Black-crowned Night Heron and Grey Heron chicks were elevated to lead and cadmium concentrations in the diet. Therefore, we suggest that lead and cadmium concentrations in heron feathers reflect contamination of breeding sites and are useful bioindicators of local contamination.

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.

Rice fields have traditionally been considered key feeding grounds for many waterbird species, including herons. Studies show that field management and flooding cycles influence the reproductive parameters of these birds. L'Albufera de València, on the east coast of the Iberian Peninsula, has large areas of rice fields and is home to the third largest breeding colony of herons in Spain. Changes in water and rice field management that have occurred since the colony was last assessed (1990) may have affected the colony's reproductive performance. Clutch and brood size, and hatching, nesting and breeding success were estimated for Grey Heron Ardea cinerea, Purple Heron Ardea purpurea, Cattle Egret Bubulcus ibis, Little Egret Egretta garzetta, Squacco Heron Ardeola ralloides (Ardeidae) and Glossy Ibis Plegadis falcinellus (Threskiornithidae) in 2015–2017. The extent of flooding and cultivation of rice fields was assessed from February 2016 to June 2017. Reproductive parameters were related to the state of the rice fields. All reproductive output parameters were lower than those reported in the literature. In 2016, laying started earlier (at the end of April), when the fields were still dry and hatching started from May, after flooding. In 2017, peak hatching occurred in June, when the fields were sown. A significant relationship was found between breeding success and the area of sown fields, except for the Squacco Heron. We found that birds that initiated egg laying closer to the date of flooding had a relatively higher breeding success for the Little Egret, Glossy Ibis, Cattle Egret and Purple Heron. The success of nesting populations in this type of artificial wetland requires water management plans that synchronize flooding regimes and maintenance of flooded areas with the biological requirements of these species.

Capsule Aquatic insects made up a relatively small part of the Grey Heron’s diet, while Little Egrets consumed numerous beetles, both aquatic and terrestrial. Aims To explore the extent of insect predation by Grey Herons and Little Egrets. Regurgitated pellets were collected from beneath trees in which herons and egrets were nesting. Methods Seventy Grey Heron and 48 Little Egret pellets were collected from the RSPB reserve at Northward Hill, Kent. These pellets were disaggregated and prey items were collected and sorted under a binocular microscope. Results Grey Herons fed on a relatively small number of aquatic beetles (Coleoptera: seven species, 32 individuals) and bugs (Hemiptera: two species, six individuals). Little Egrets, in contrast, fed on a diverse array of beetle species, both aquatic (three families, 11 species, 48 individuals) and terrestrial (10 families, 35 species, 111 individuals), and also a few aquatic bugs (one family, one species, three individuals). The extent of terrestrial beetles in the diet constitutes new information for Little Egrets. Conclusion Insects, both terrestrial and aquatic, represent an important component of the diet of Little Egrets. For Grey Herons, insects are a very minor component of the diet, involving aquatic species only.

Breeding Great Cormorants Phalacrocorax carbo have been rapidly increasing in Italy since the 1990s, and have settled their colonies in sites already used by other colonial waterbirds. We investigated the patterns of interference between Grey Herons Ardea cinerea and Great Cormorants, the two species most prone to competition due to their similar preference for nest sites. The analysis of long-term population trends in colonies with both species compared to colonies without Cormorants, showed that the number of Grey Heron nests gradually decreased following the settlement of Great Cormorants. The two species exhibited a gradual spatial segregation in nest location, both horizontally and vertically, within the same colony. In some heronries we found clear examples of interaction, but we also report cases where the interaction was less clear. Thus, although Great Cormorants might be competitively dominant over Grey Herons for nest site occupancy in many of their shared colonies, the spatial competition dynamics might also be influenced by factors affecting population dynamics in the wider environment. We envisage specific observations and focus on areas with an apparent abundance of trees suitable for nesting by both species.

We compared the concentrations of 17 heavy metals and essential elements in post-hatching eggshells of two waterbirds, the obligate piscivorous great cormorant Phalacrocorax carbo (GCM) and the more omnivorous grey heron Ardea cinerea (GHR), breeding sympatrically in eight mixed colonies in Poland. We found significant inter-species and inter-colony differences in the levels of most of the elements. GHR had significantly higher concentrations of Al, which can be explained by its very low stomach pH: an acidic environment favours the release of Al compounds. Differences in Mn, Ni, Cu, Se and Hg concentrations can be attributed to the various contributions of fish and other aquatic organisms to the diet, and to the exploration of different habitats (GCM exclusively aquatic, GHR a wider range) and microhabitats (GCM, in contrast to wading GHR, dive for food, exploring the whole depth range of water bodies), differently exposed to contamination by those elements from sediments. Inter-colony differences were related to the level of industrialisation. We recorded higher levels of some elements in the eggshells (Fe, Mn in both species and Cr, Ni and Zn in GCM) collected in industrialised areas, which may be associated with the negative environmental impact of industrial areas.