-We examined the diet of Long-tailed Ducks (Clangula hyemalis) in the autumn and winter of 1998-99 in the Belcher Islands, Nunavut, Canada. Collections were made in early November before sea ice had formed and in February and March, the time of maximum ice cover. Eight birds collected in the autumn and 19 collected in the winter had food items in the proventriculus/esophagus. For birds collected in the fall, 89% (aggregate wet mass) of the diet consisted of the amphipod Calliopius laeviusculus. The remainder consisted of other smaller amphipods (5%) and sandlance (sandeels, Ammodytes sp.; 6%). In winter, Long-tailed Duck diet consisted of the amphipod Ischyrocerus anquipes (69%), fish eggs (probably sandlance; 24%), sandlance (1%) and other amphipods (5%). Longtailed Duck foraging at the landfast ice floe edge along coasts fed mostly on fish and fish eggs, while those in polynyas among islands fed on amphipods. Consuming soft-bodied prey with high energy densities is likely to allow Longtailed Ducks to successfully winter in the predominately ice-covered Hudson Bay. Received 21 December 2000, accepted 10 January 2001.
{"title":"Autumn and Winter Diet of Long-Tailed Duck in the Belcher Islands, Nunavut, Canada","authors":"S. Jamieson, G. Robertson, H. Gilchrist","doi":"10.2307/1522253","DOIUrl":"https://doi.org/10.2307/1522253","url":null,"abstract":"-We examined the diet of Long-tailed Ducks (Clangula hyemalis) in the autumn and winter of 1998-99 in the Belcher Islands, Nunavut, Canada. Collections were made in early November before sea ice had formed and in February and March, the time of maximum ice cover. Eight birds collected in the autumn and 19 collected in the winter had food items in the proventriculus/esophagus. For birds collected in the fall, 89% (aggregate wet mass) of the diet consisted of the amphipod Calliopius laeviusculus. The remainder consisted of other smaller amphipods (5%) and sandlance (sandeels, Ammodytes sp.; 6%). In winter, Long-tailed Duck diet consisted of the amphipod Ischyrocerus anquipes (69%), fish eggs (probably sandlance; 24%), sandlance (1%) and other amphipods (5%). Longtailed Duck foraging at the landfast ice floe edge along coasts fed mostly on fish and fish eggs, while those in polynyas among islands fed on amphipods. Consuming soft-bodied prey with high energy densities is likely to allow Longtailed Ducks to successfully winter in the predominately ice-covered Hudson Bay. Received 21 December 2000, accepted 10 January 2001.","PeriodicalId":266321,"journal":{"name":"Waterbirds: The International Journal of Waterbird Biology","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129780318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
-The three South American flamingos, Chilean Flamingo (Phoenicopterus chilensis), Andean Flamingo (Phoenicoparrus andinus) and James' Flamingo (Phoenicoparrus jamesi), coexist in Laguna de Pozuelos (ujuy Province, northwestern Argentina). This lake is an important overwintering habitat for Andean and James' Flamingos. The Chilean Flamingo is the predominant species and the only one breeding on the lake. This study was conducted from 1992 to 1995, during a period of drought. I report changes in the habitat conditions and how they affect the presence and abundance of flamingo species. Results indicate that in years of below average rainfall, the number of flamingos decreased appreciably, and their expected seasonal pattern of abundance is affected. Chilean Flamingo abundance showed a positive association with the size of the lake, possibly related to the scarcity of deep foraging areas. Zooplankton was lacking, so the presence of Chilean Flamingo might not be related to it. Diatom density was not a limiting resource for James and Andean Flamingos. James' Flamingo preferred to feed near the banks, and was favored by the availability of shallow foraging habitats as the lake contracted. Flamingos recorded in Laguna de Pozuelos represent a fraction of their entire populations within the high-Andes wetland complex. In this context, Pozuelos is an important habitat for flamingos and one of the main breeding grounds for Chilean Flamingo at high altitudes. Received 20 August 2000, accepted 21 December 2000.
{"title":"Habitat Changes in Laguna de Pozuelos, Jujuy, Argentina: Implications for South American Flamingo Populations","authors":"V. Mascitti","doi":"10.2307/1522238","DOIUrl":"https://doi.org/10.2307/1522238","url":null,"abstract":"-The three South American flamingos, Chilean Flamingo (Phoenicopterus chilensis), Andean Flamingo (Phoenicoparrus andinus) and James' Flamingo (Phoenicoparrus jamesi), coexist in Laguna de Pozuelos (ujuy Province, northwestern Argentina). This lake is an important overwintering habitat for Andean and James' Flamingos. The Chilean Flamingo is the predominant species and the only one breeding on the lake. This study was conducted from 1992 to 1995, during a period of drought. I report changes in the habitat conditions and how they affect the presence and abundance of flamingo species. Results indicate that in years of below average rainfall, the number of flamingos decreased appreciably, and their expected seasonal pattern of abundance is affected. Chilean Flamingo abundance showed a positive association with the size of the lake, possibly related to the scarcity of deep foraging areas. Zooplankton was lacking, so the presence of Chilean Flamingo might not be related to it. Diatom density was not a limiting resource for James and Andean Flamingos. James' Flamingo preferred to feed near the banks, and was favored by the availability of shallow foraging habitats as the lake contracted. Flamingos recorded in Laguna de Pozuelos represent a fraction of their entire populations within the high-Andes wetland complex. In this context, Pozuelos is an important habitat for flamingos and one of the main breeding grounds for Chilean Flamingo at high altitudes. Received 20 August 2000, accepted 21 December 2000.","PeriodicalId":266321,"journal":{"name":"Waterbirds: The International Journal of Waterbird Biology","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131536608","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
-Common Terns (Sterna hirundo), which breed in North America and migrate into the southern hemisphere in winter, show a wide nonbreeding distribution that includes the Atlantic coasts of Argentina and Brazil. At Punta Rasa (Samborombon Bay, Argentina), there were about 30,000 Common Terns. Their diet in winter was assessed by the analysis of regurgitated pellets collected at Punta Rasa. Adult Coleoptera, Odonata, Orthoptera and Hemiptera were the main insects found in the diet. A total of 14 species of fishes were identified. Argentine Anchovy (Engraulis anchoita) and Anchovy (Anchoa marinii) (Family Engraulidae), represented 79% by number and the 78% of the consumed biomass of fish prey. The average length of fish prey was 90.0 ? 17.6 mm. Half the prey lived in seawater, while the other half was taken in estuarine or seawater. There was no evidence of fish prey taken by terns foraging in freshwater habitats. Total consumption of food was estimated as 106 tons of fish (most of themjuvenile) during a five month period at Punta Rasa. Received 6 August 2000, accepted 9 December 2000.
{"title":"Food and Feeding Biology of the Common Tern during the Nonbreeding Season in Samborombon Bay, Buenos Aires, Argentina","authors":"Laura Mauco, M. Favero, M. Bó","doi":"10.2307/1522247","DOIUrl":"https://doi.org/10.2307/1522247","url":null,"abstract":"-Common Terns (Sterna hirundo), which breed in North America and migrate into the southern hemisphere in winter, show a wide nonbreeding distribution that includes the Atlantic coasts of Argentina and Brazil. At Punta Rasa (Samborombon Bay, Argentina), there were about 30,000 Common Terns. Their diet in winter was assessed by the analysis of regurgitated pellets collected at Punta Rasa. Adult Coleoptera, Odonata, Orthoptera and Hemiptera were the main insects found in the diet. A total of 14 species of fishes were identified. Argentine Anchovy (Engraulis anchoita) and Anchovy (Anchoa marinii) (Family Engraulidae), represented 79% by number and the 78% of the consumed biomass of fish prey. The average length of fish prey was 90.0 ? 17.6 mm. Half the prey lived in seawater, while the other half was taken in estuarine or seawater. There was no evidence of fish prey taken by terns foraging in freshwater habitats. Total consumption of food was estimated as 106 tons of fish (most of themjuvenile) during a five month period at Punta Rasa. Received 6 August 2000, accepted 9 December 2000.","PeriodicalId":266321,"journal":{"name":"Waterbirds: The International Journal of Waterbird Biology","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117059789","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
-During the winter months Snowy Egrets (Egretta thula) often form feeding associations with Redbreasted Mergansers (Mergus serrator) at Bolsa Chica Ecological Reserve, Orange County, California. We quantified and compared foraging success of egrets feeding in associations with success of egrets feeding independently. During winter 1996-1997, egrets feeding with mergansers increased their rate of prey acquisition by increasing both their striking rate (strikes/min) and their striking efficiency (captures/strike). In contrast, during winter 1997-98 we found no differences in the rate of prey acquisition between egrets feeding independently and those feeding in association with mergansers. Although we did not quantify the size of prey taken, egrets feeding in associations in 1997-1998 may have captured larger prey than those that were feeding alone. Egrets may benefit from feeding in associations with mergansers by increasing their prey capture rate and/or by capturing larger prey. Received 15 September 2000, accepted 3 October 2000.
{"title":"Feeding Associations between Snowy Egrets and Red-Breasted Mergansers","authors":"J. Bennett, W. Smithson","doi":"10.2307/1522252","DOIUrl":"https://doi.org/10.2307/1522252","url":null,"abstract":"-During the winter months Snowy Egrets (Egretta thula) often form feeding associations with Redbreasted Mergansers (Mergus serrator) at Bolsa Chica Ecological Reserve, Orange County, California. We quantified and compared foraging success of egrets feeding in associations with success of egrets feeding independently. During winter 1996-1997, egrets feeding with mergansers increased their rate of prey acquisition by increasing both their striking rate (strikes/min) and their striking efficiency (captures/strike). In contrast, during winter 1997-98 we found no differences in the rate of prey acquisition between egrets feeding independently and those feeding in association with mergansers. Although we did not quantify the size of prey taken, egrets feeding in associations in 1997-1998 may have captured larger prey than those that were feeding alone. Egrets may benefit from feeding in associations with mergansers by increasing their prey capture rate and/or by capturing larger prey. Received 15 September 2000, accepted 3 October 2000.","PeriodicalId":266321,"journal":{"name":"Waterbirds: The International Journal of Waterbird Biology","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126983176","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
-Recruitment is the process by which young birds are added to the breeding population. The two most commonly used methods to estimate recruitment in ducks are pair/brood counts, and fall age ratios based on wings returned by hunters. Direct counts on the wintering area to determine the proportion of young males to adult males (age ratios), can be used for species with delayed plumage maturation. This is useful for species that are difficult to study on the breeding grounds and are seldom hunted, such as Harlequin Ducks (Histrionicus histrionicus). Such an approach is only valid if age classes are equally sampled. Between 1994 and 1999, the proportion of male Harlequin Ducks that were immatures in the Strait of Georgia, British Columbia, was estimated at 0.068. The proportions differed across years. Little difference occurred through the winter months until spring, when there was a significant increase in proportions in March. If these age ratios are accurate, then recruitment would not be compensating for annual adult mortality and the population could have been declining during the period of our study. However, if immature males are not distributed evenly among the population, then our assessment may underestimate or overestimate proportions. Delayed breeding means that immature birds experience several additional seasons of mortality prior to breeding, and thus the actual recruitment rate into the breeding population would be lower than that presented here. Received 11 April 2000, accepted 18July 2000.
{"title":"Winter Age Ratios and the Assessment of Recruitment of Harlequin Ducks","authors":"Cyndi M. Smith, R. Goudie, F. Cooke","doi":"10.2307/1522241","DOIUrl":"https://doi.org/10.2307/1522241","url":null,"abstract":"-Recruitment is the process by which young birds are added to the breeding population. The two most commonly used methods to estimate recruitment in ducks are pair/brood counts, and fall age ratios based on wings returned by hunters. Direct counts on the wintering area to determine the proportion of young males to adult males (age ratios), can be used for species with delayed plumage maturation. This is useful for species that are difficult to study on the breeding grounds and are seldom hunted, such as Harlequin Ducks (Histrionicus histrionicus). Such an approach is only valid if age classes are equally sampled. Between 1994 and 1999, the proportion of male Harlequin Ducks that were immatures in the Strait of Georgia, British Columbia, was estimated at 0.068. The proportions differed across years. Little difference occurred through the winter months until spring, when there was a significant increase in proportions in March. If these age ratios are accurate, then recruitment would not be compensating for annual adult mortality and the population could have been declining during the period of our study. However, if immature males are not distributed evenly among the population, then our assessment may underestimate or overestimate proportions. Delayed breeding means that immature birds experience several additional seasons of mortality prior to breeding, and thus the actual recruitment rate into the breeding population would be lower than that presented here. Received 11 April 2000, accepted 18July 2000.","PeriodicalId":266321,"journal":{"name":"Waterbirds: The International Journal of Waterbird Biology","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125741323","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
-Longlining has been encouraged in Peru as an opportunity for small-scale fishermen to reduce cetacean mortality in gill nets. Very little is known about seabird by-catch in this longline fishery. In January 1999, we conducted surveys in five fishing villages in northern Peru to estimate seabird by-catch and 29 fishermen were interviewed. Eighty percent of the fishermen used frozen bait, which increases the probability of seabird mortality. Ninety percent of fishermen confirmed that birds are hooked while setting the gear. Additionally, we found that over 40% of hooked seabirds were albatrosses. The most common albatross off northern Peru is the Waved Albatross (Phoebastria irrorata) and about 60% of the population of the Chatham Island Albatross (Thalassarche eremita) winters off Peru. Both species are considered threatened due to their small population sizes. Seabird by-catch in the Peruvian small-scale longline fishery should be of conservation concern; pooled estimates of by-catch rates based on interviews were 1 to 2 birds/1,000 hooks. The estimated by-catch of albatrosses by the entire fleet is likely to lie between 2,370 and 5,610 birds each year, which represents between 5% and 13% of the pooled populations of the Waved and Chatham Island Albatrosses. Even though these numbers are extrapolations, they can be considered a rough indicator of the magnitude of the seabird by-catch by the small-scale longline fishery in Peru. Further research that includes onboard seabird by-catch surveys as well as a larger sample of interviews with fishermen are required. Public awareness that encourages the implementation of by-catch deterrence measures such as bird lines, night setting of hooks, and the use of fresh bait, will help reduce by-catch and bait loss, thus benefiting fishermen and promoting albatross conservation. Received 10 July, accepted 28 September 2000.
{"title":"Seabird By-Catch in Small-Scale Longline Fisheries in Northern Peru","authors":"J. Jahncke, E. Goya, A. Guillén","doi":"10.2307/1522255","DOIUrl":"https://doi.org/10.2307/1522255","url":null,"abstract":"-Longlining has been encouraged in Peru as an opportunity for small-scale fishermen to reduce cetacean mortality in gill nets. Very little is known about seabird by-catch in this longline fishery. In January 1999, we conducted surveys in five fishing villages in northern Peru to estimate seabird by-catch and 29 fishermen were interviewed. Eighty percent of the fishermen used frozen bait, which increases the probability of seabird mortality. Ninety percent of fishermen confirmed that birds are hooked while setting the gear. Additionally, we found that over 40% of hooked seabirds were albatrosses. The most common albatross off northern Peru is the Waved Albatross (Phoebastria irrorata) and about 60% of the population of the Chatham Island Albatross (Thalassarche eremita) winters off Peru. Both species are considered threatened due to their small population sizes. Seabird by-catch in the Peruvian small-scale longline fishery should be of conservation concern; pooled estimates of by-catch rates based on interviews were 1 to 2 birds/1,000 hooks. The estimated by-catch of albatrosses by the entire fleet is likely to lie between 2,370 and 5,610 birds each year, which represents between 5% and 13% of the pooled populations of the Waved and Chatham Island Albatrosses. Even though these numbers are extrapolations, they can be considered a rough indicator of the magnitude of the seabird by-catch by the small-scale longline fishery in Peru. Further research that includes onboard seabird by-catch surveys as well as a larger sample of interviews with fishermen are required. Public awareness that encourages the implementation of by-catch deterrence measures such as bird lines, night setting of hooks, and the use of fresh bait, will help reduce by-catch and bait loss, thus benefiting fishermen and promoting albatross conservation. Received 10 July, accepted 28 September 2000.","PeriodicalId":266321,"journal":{"name":"Waterbirds: The International Journal of Waterbird Biology","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124877045","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
--Analysis of Christmas Bird Count (CBC) data for the Honolulu, HI area showed a population which dropped following the strong 1982-1983 ENSO (El Nifio Southern Oscillation) to 4% of its pre-ENSO value for Great Frigatebirds (Fregata minor) and to 35% for Red-footed Boobies (Sula sula). The time for the populations to regain their pre-ENSO values was over a decade. CBC data for the Farallon Islands, CA shows a less striking but still significant decrease in populations of Brandt's Cormorants (Phalacrocorax penicillatus), Pelagic Cormorants (P pelagicus), and Common Murres (Uria aalge) following the 1982-1983 ENSO. Both the Hawaii and Farrallon Islands data exhibit longer term correlations with the Pacific Decadal Oscillation (PDO). Populations are suppressed during the warm phase of the PDO. CBC data for some California and Oregon coastal areas showed some weaker indications of an ENSO effect for the latter three species but little indication of a PDO effect. Received 21January 2000, accepted 20 April 2000.
{"title":"Effects of ENSO and PDO Events on Seabird Populations as Revealed by Christmas Bird Count Data","authors":"R. Vandenbosch","doi":"10.2307/1522178","DOIUrl":"https://doi.org/10.2307/1522178","url":null,"abstract":"--Analysis of Christmas Bird Count (CBC) data for the Honolulu, HI area showed a population which dropped following the strong 1982-1983 ENSO (El Nifio Southern Oscillation) to 4% of its pre-ENSO value for Great Frigatebirds (Fregata minor) and to 35% for Red-footed Boobies (Sula sula). The time for the populations to regain their pre-ENSO values was over a decade. CBC data for the Farallon Islands, CA shows a less striking but still significant decrease in populations of Brandt's Cormorants (Phalacrocorax penicillatus), Pelagic Cormorants (P pelagicus), and Common Murres (Uria aalge) following the 1982-1983 ENSO. Both the Hawaii and Farrallon Islands data exhibit longer term correlations with the Pacific Decadal Oscillation (PDO). Populations are suppressed during the warm phase of the PDO. CBC data for some California and Oregon coastal areas showed some weaker indications of an ENSO effect for the latter three species but little indication of a PDO effect. Received 21January 2000, accepted 20 April 2000.","PeriodicalId":266321,"journal":{"name":"Waterbirds: The International Journal of Waterbird Biology","volume":"105 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117230085","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
-I made 69 monthly censuses of Caribbean Flamingos (Phoenicopterus ruber ruber) from June 1990 to September 1996 in the Los Olivitos Wildlife Refuge and Fishing Reserve, western Venezuela, to determine temporal and spatial variation in abundance. Overall, the total number of flamingos increased from a mean of 3,092/month in 1990, to a mean of 8,206/month in 1995. Flamingos were most abundant in October (mean = 8,567) and November (mean = 9,183), especially in 1990, 1994, and 1995. The highest number of birds (20,000) occurred in October 1994, when monthly rainfall was also highest. Birds were few or sometimes absent from February to April. Fiftyfive percent of the birds used the central and northeast open-water area of El Arroyo, but 25% also used the outlet area of Cafio Viejo. Human intervention included the frequent presence of fisherman and their boats, and sometimes the use of Los Olivitos as a target area during military exercises in nearby areas. Dike construction by the solar saltworks may have covered about 2,500 ha of possible feeding area for flamingos, but flamingos started to feed in the saltworks (Concentrator 1) even before construction ended. MONITOREO DE FLAMENCOS CARIBEROS EN EL REFUGIO DE FAUNA LOS OLIVITOS EN EL OESTE DE VENEZUELA Resumen.-A fin de determinar la abundancia espacial y temporal del flamenco caribefio (Phoenicopterus ruber ruber) en el Refugio de Fauna Silvestre y Reserva de Pesca Cienaga de Los Olivitos, Venezuela occidental, se efectuaron 69 censos mensuales entrejunio de 1990 y septiembre de 1996. En general, se observ6 un incremento en el n6mero total de flamencos, desde un promedio de 3.092/mes en 1990 hasta un promedio de 8.206/mes en 1995. Los flamencos fueron mis abundantes en octubre (promedio = 8.567) y noviembre (promedio = 9.183), especialmente en 1990, 1994 y 1995. El nfimero mayor de aves (20.000) ocurri6 en octubre de 1994, lo cual coincidi6 con el valor mensual mis alto de precipitaci6n. De febrero a abril, se observaron pocos flamencos o estaban ausentes. El 55% de las aves utilizaron las albuferas centro y noreste del sector El Arroyo, pero tambi6n, un 25% usaron el airea aledafia a la desembocadura del Cafio Viejo. Las perturbaciones humanas incluyeron la presencia de lanchas y pescadores en forma frecuente y en ocasiones el uso de la cienaga como airea de impactaci6n (blanco) por las prdicticas militares realizadas en las dreas adyacentes. Por otro lado, la construcci6n de diques correspondiente a la empresa industrial de sal, posiblemente afect6 aproximadamente 2.500 ha de area disponible para la alimentaci6n de los flamencos. Aparentemente, esto s6lo afect6 a las aves en su etapa inicial, dado que se observaron alimentindose dentro de los mismos (Concentrador 1), ain antes de que se finalizaran los trabajos de construcci6n.
{"title":"Monitoring Caribbean Flamingos at Los Olivitos Wildlife Refuge, Western Venezuela","authors":"Daria E. Pirela","doi":"10.2307/1522153","DOIUrl":"https://doi.org/10.2307/1522153","url":null,"abstract":"-I made 69 monthly censuses of Caribbean Flamingos (Phoenicopterus ruber ruber) from June 1990 to September 1996 in the Los Olivitos Wildlife Refuge and Fishing Reserve, western Venezuela, to determine temporal and spatial variation in abundance. Overall, the total number of flamingos increased from a mean of 3,092/month in 1990, to a mean of 8,206/month in 1995. Flamingos were most abundant in October (mean = 8,567) and November (mean = 9,183), especially in 1990, 1994, and 1995. The highest number of birds (20,000) occurred in October 1994, when monthly rainfall was also highest. Birds were few or sometimes absent from February to April. Fiftyfive percent of the birds used the central and northeast open-water area of El Arroyo, but 25% also used the outlet area of Cafio Viejo. Human intervention included the frequent presence of fisherman and their boats, and sometimes the use of Los Olivitos as a target area during military exercises in nearby areas. Dike construction by the solar saltworks may have covered about 2,500 ha of possible feeding area for flamingos, but flamingos started to feed in the saltworks (Concentrator 1) even before construction ended. MONITOREO DE FLAMENCOS CARIBEROS EN EL REFUGIO DE FAUNA LOS OLIVITOS EN EL OESTE DE VENEZUELA Resumen.-A fin de determinar la abundancia espacial y temporal del flamenco caribefio (Phoenicopterus ruber ruber) en el Refugio de Fauna Silvestre y Reserva de Pesca Cienaga de Los Olivitos, Venezuela occidental, se efectuaron 69 censos mensuales entrejunio de 1990 y septiembre de 1996. En general, se observ6 un incremento en el n6mero total de flamencos, desde un promedio de 3.092/mes en 1990 hasta un promedio de 8.206/mes en 1995. Los flamencos fueron mis abundantes en octubre (promedio = 8.567) y noviembre (promedio = 9.183), especialmente en 1990, 1994 y 1995. El nfimero mayor de aves (20.000) ocurri6 en octubre de 1994, lo cual coincidi6 con el valor mensual mis alto de precipitaci6n. De febrero a abril, se observaron pocos flamencos o estaban ausentes. El 55% de las aves utilizaron las albuferas centro y noreste del sector El Arroyo, pero tambi6n, un 25% usaron el airea aledafia a la desembocadura del Cafio Viejo. Las perturbaciones humanas incluyeron la presencia de lanchas y pescadores en forma frecuente y en ocasiones el uso de la cienaga como airea de impactaci6n (blanco) por las prdicticas militares realizadas en las dreas adyacentes. Por otro lado, la construcci6n de diques correspondiente a la empresa industrial de sal, posiblemente afect6 aproximadamente 2.500 ha de area disponible para la alimentaci6n de los flamencos. Aparentemente, esto s6lo afect6 a las aves en su etapa inicial, dado que se observaron alimentindose dentro de los mismos (Concentrador 1), ain antes de que se finalizaran los trabajos de construcci6n.","PeriodicalId":266321,"journal":{"name":"Waterbirds: The International Journal of Waterbird Biology","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115474443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Social and Reproductive Relationships of Captive Caribbean Flamingos","authors":"P. W. Shannon","doi":"10.2307/1522162","DOIUrl":"https://doi.org/10.2307/1522162","url":null,"abstract":"","PeriodicalId":266321,"journal":{"name":"Waterbirds: The International Journal of Waterbird Biology","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122750894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
G. Luna‐Jorquera, S. Garthe, Felipe G. Sepulveda, Tanja Weichler, J. Vásquez
-The Humboldt Penguin (Spheniscus humboldti) has been reported as declining along its distributional range and has recently been classified as vulnerable. The actual size of the Humboldt Penguin population is still unknown, and a complete population assessment is required. Here we present a study combining both counts of molting birds on land and counts of birds at sea during the molting period. We conducted our study in the Coquimbo Region, Northern Chile, and found 7,619 birds on land and 2,700 at sea, adding up to a total of about 10,300 Humboldt Penguins during the molting season (February 1999). Since these numbers are much higher than all other recent estimates, we emphasize that assessment on land and at sea need to be combined to provide more reliable estimates. Received 20July 1999, accepted 15July 2000.
{"title":"Population size of Humboldt penguins assessed by combined terrestrial and at-sea counts","authors":"G. Luna‐Jorquera, S. Garthe, Felipe G. Sepulveda, Tanja Weichler, J. Vásquez","doi":"10.2307/1522191","DOIUrl":"https://doi.org/10.2307/1522191","url":null,"abstract":"-The Humboldt Penguin (Spheniscus humboldti) has been reported as declining along its distributional range and has recently been classified as vulnerable. The actual size of the Humboldt Penguin population is still unknown, and a complete population assessment is required. Here we present a study combining both counts of molting birds on land and counts of birds at sea during the molting period. We conducted our study in the Coquimbo Region, Northern Chile, and found 7,619 birds on land and 2,700 at sea, adding up to a total of about 10,300 Humboldt Penguins during the molting season (February 1999). Since these numbers are much higher than all other recent estimates, we emphasize that assessment on land and at sea need to be combined to provide more reliable estimates. Received 20July 1999, accepted 15July 2000.","PeriodicalId":266321,"journal":{"name":"Waterbirds: The International Journal of Waterbird Biology","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125448106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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