| 1. |
- Larson, Keith W., et al.
(författare)
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Digiscoping Vouchers for Diet Studies in Bill-load Holding Birds
- 2006
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Ingår i: Waterbirds (De Leon Springs, Fla.). - 1524-4695 .- 1938-5390. ; 29:2, s. 198-202
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Tidskriftsartikel (refereegranskat)abstract
- We conducted an observer-based diet study of Caspian Terns (Sterna caspia) incorporating digiscoping to collect digital photographic vouchers of fish. Observer-based diet studies pose several problems, ranging from differential experience and abilities of observers to the lack of vouchers for confirming identification. One solution to these problems is to recover fish either directly from birds (i.e., trapping, shooting) or ones dropped on the colony. This may not, however, be desirable or achieve adequate sample sizes. Some species are difficult to capture or methods may cause significant disturbance and/or nest abandonment. To overcome these problems, we used a relatively inexpensive new photographic technique known as digiscoping. By holding a high-resolution point-and-shoot digital camera up to the eyepiece of a spotting scope or pair of binoculars, we could take digital photographic vouchers of fish as terns brought them into the colony. During the study, we made 16,423 observations, identifying 92% of the fish to the family (3%), genus (15%), or species (74%) level. We supported these observations with over 2,500 digital photograph vouchers. Vouchers confirmed identification of all fish taxa and allowed for later identification, by us or qualified fisheries biologists, of several species unidentifiable in the field. The ability to have independent experts confirm observations and identify previously unidentifiable observations greatly expanded our understanding of the range of fish taken by Caspian Terns.
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| 2. |
- Larson, Keith W., et al.
(författare)
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Wintering Black Terns Foraging Among Manta Rays in Coastal Guerrero, Mexico
- 2007
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Ingår i: Waterbirds (De Leon Springs, Fla.). - 1524-4695 .- 1938-5390. ; 30:3, s. 448-449
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Tidskriftsartikel (refereegranskat)abstract
- Winter observations of Black Terns (Chlidonias niger) in Mexico are rare. On 19 January 2007, we observed over 3,000 Black Terns foraging among hundreds of breaching manta rays one kilometer offshore on the coast of Guerrero, Mexico.
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| 3. |
- Barshep, Yahkat, et al.
(författare)
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Impact of Climate and Predation on Autumn Migration of the Curlew Sandpiper
- 2011
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Ingår i: Waterbirds. - 1524-4695. ; 34:1, s. 41283-41283
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Tidskriftsartikel (refereegranskat)abstract
- Using constant-effort catch data, causes of annual variation in the timing of migration of Curlew Sandpipers (Calidris ferruginea) migrating through Ottenby, Sweden, as well as the trend in timing of migration from 1946-2005, was investigated. Variation in the timing of autumn migration of adult and juvenile Curlew Sandpipers was influenced by breeding success connected to predation pressure on the Arctic breeding grounds. Median migration date of adult birds was significantly later in good breeding years compared with poor breeding years while the migration of juveniles was earlier in good breeding years compared with poor breeding years. Also, adults migrated earlier when the average temperature in June was warmer. Median migration dates of adults have advanced by 23 days from 1946-2005, but the migration dates of juveniles have remained unchanged. Unchanged migration dates of juveniles indicate that earlier departure of the adult Curlew Sandpipers from the breeding grounds was not due to earlier breeding. Evidence suggests that declining breeding productivity as a result of increasing predation on broods of shorebirds might, over the years, be the reason for the observed pattern of early departure of adults from the breeding grounds. One possible consequence of earlier migration is a mismatch between timing of migration and periods of food abundance on migration routes and at the wintering grounds, leading to a decline in adult and juvenile survival and population size. Received 24 February 2010, accepted 30 September 2010.
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| 4. |
- Collis, Ken, et al.
(författare)
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Trends in Caspian Tern Nesting and Diet in San Francisco Bay : Conservation Implications for Terns and Salmonids
- 2012
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Ingår i: Waterbirds (De Leon Springs, Fla.). - : Waterbird Society. - 1524-4695 .- 1938-5390. ; 35:1, s. 25-34
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Tidskriftsartikel (refereegranskat)abstract
- Colony size, nesting ecology and diet of Caspian Terns (Hydroprogne caspia) were investigated in the San Francisco Bay area (SFBA) during 2003-2009 to assess the potential for conservation of the tern breeding population and possible negative effects of predation on survival of juvenile salmonids (Oncorhyn-chusspp.). Numbers of breeding Caspian Terns declined 36% from 2003 to 2009, mostly due to abandonment of the Knight Island colony and decline of the Brooks Island colony, the two largest colonies in the SFBA. Concurrently, nesting success declined 69% associated with colony site characteristics such as (a) quality and quantity of nesting substrate, (b) vulnerability to nest predators, (c) displacement by other colonial waterbirds and (d) human disturbance. Marine fishes were the predominant prey in tern diets from the SFBA; however, diet composition varied among colonies. Juvenile salmonids comprised 22.9% of the diet of terns nesting in the North Bay, 5.3% of diet of terns nesting in the Central Bay, and 0.1% in the South Bay. Construction or restoration of nesting islands in the South Bay may help maintain and restore breeding Caspian Terns without enhancing mortality of salmonid stocks of conservation concern.
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| 5. |
- Craig, David P., et al.
(författare)
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Migratory Connectivity of North American Caspian Tern (Hydroprogne caspia) Populations
- 2017
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Ingår i: Waterbirds (De Leon Springs, Fla.). - : The Waterbird Society. - 1524-4695 .- 1938-5390. ; 40:1, s. 58-62
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Tidskriftsartikel (refereegranskat)abstract
- Migratory connectivity of Caspian Terns (Hydroprogne caspia) was investigated using individuals marked in North America between 1922 and 2015. The results support recent genetic work describing three breeding regions (Pacific, Great Lakes, and Central Canada). Further., our results show strong migratory connectivity of Pacific breeders to wintering regions in central and western Mexico, and connectivity of Great Lakes breeders to wintering regions in the Gulf of Mexico and Caribbean. This integrated picture of demographic connectivity throughout North America should help in planning more effective management of the species.
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| 6. |
- Källander, Hans
(författare)
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Intraspecific Kleptoparasitism in the Common Coot (Fulica atra)
- 2013
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Ingår i: Waterbirds. - 1524-4695. ; 36:2, s. 225-227
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Tidskriftsartikel (refereegranskat)abstract
- In late fall and early winter > 2,000 Common Coots (Fulica atra) may gather on the small, shallow Lake Krankesjon in southern Sweden, where they dive for submerged plants. Casual observations indicated that intraspecific kleptoparasitism was common throughout these flocks. Kleptoparasitic attacks mostly occurred shortly after a Common Coot surfaced with food and before it had ingested much of it. Attacked birds rarely resisted, and kleptoparasitic individuals had a success rate of 85% (n = 290), including cases when the victim managed to keep part of the food. Kleptoparasitic Common Coots used a mixed strategy, alternating between parasitism and self-feeding. Received 26 November 2012, accepted 27 November 2012.
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| 7. |
- Nilsson, Leif, et al.
(författare)
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Numbers of mute swans and Whooper Swans in Sweden, 1967-2000
- 2002
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Ingår i: Waterbirds. - 1524-4695. ; 25:Suppl 1, s. 53-60
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Tidskriftsartikel (refereegranskat)abstract
- Mute Swans (Cygnus olor) and Whooper Swans (Cygnus cygnus) in Sweden have been monitored as part of the International Waterbird Census (IWC) since 1967. For the Whooper Swan, midwinter indices show fluctuations around a slowly increasing trend. Country-wide surveys in 1971-72, 1988-89, 1995 and 2000, however found a more substantial increase in numbers, with national totals estimated at 2,000, 4,000, 8,000 and 8,000 individuals, respectively. The difference between the trends indices and the results of the country-wide surveys is attributable to the birds using more terrestrial habitats since the early 1980s, which are less well covered by the IWC. In 1995, 33% of the swans were found on land, compared to 43% in January 2000. For the Mute Swan, the midwinter indices showed a significantly increasing trend from 1970 to 2000, whereas autumn indices from September counts fluctuated around a more or less stable level, but with a decrease in the last few years. Country-wide midwinter counts recorded about 8,000 Mute Swans in 1973, 13,000 in 1988-89 and over 15,000 in january 1993.
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| 8. |
- Sarzo, Blanca, et al.
(författare)
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Bayesian Immature Survival Analysis of the Largest Colony of Common Murre (Uria aalge) in the Baltic Sea
- 2019
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Ingår i: Waterbirds (De Leon Springs, Fla.). - : Waterbird Society. - 1524-4695 .- 1938-5390. ; 42:3, s. 304-313
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Tidskriftsartikel (refereegranskat)abstract
- In long-lived species, such as seabirds, immature survival is the most important life history parameter after adult survival. The assessment of immature survival has often been difficult due to extended periods in which young birds remain unobservable at sea. This study presents results on survival of immature Common Murre (Uria aalge) obtained from an extensive mark-recapture study of a large colony at Stora Karlso in the Baltic Sea, Sweden. This colony, in contrast with other colonies, has the unique feature that many 1-year-old birds return to the colony (12%). Between 2006 and 2016, 28,930 chicks were marked at fledging, of which 5,493 individuals were later resighted in the colony. Annual survival and recapture probabilities were estimated using Bayesian Cormack-Jolly-Seber models with four age classes for survival probability, and recapture probability being age and time dependent. Informative prior distributions were used to correct partial observability problems in older age classes (observed at breeding ledges). The estimated survival probability of 1-year-old birds was 0.53 (95% CI = 0.49-0.58), 2-year-old birds was 0.87 (0.79-0.96), 3-year-old birds was 0.96 (0.90-0.99), and 4-to-10-year old bird survival probability was 0.63 (0.61-0.64). Survival estimates for younger age classes were consistent with previous studies. Several biological factors may contribute to the observed decline in survival for older age classes.
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| 9. |
- Wille, Michelle, et al.
(författare)
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Weathering the Storm of High Pathogenicity Avian Influenza in Waterbirds
- 2023
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Ingår i: Waterbirds (De Leon Springs, Fla.). - : BioOne, Waterbird Society. - 1524-4695 .- 1938-5390. ; 46:1, s. 100-109
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Tidskriftsartikel (refereegranskat)abstract
- The ongoing panzootic of bird flu caused by high pathogenicity avian influenza (HPAI) virus is unprecedented in scale, with mass mortality events causing population level effects for several waterbird species. While the panzootic commenced in 2021, a number of key events have occurred over the past decades leading to the emergence of this viral lineage. Since 2021, tens of thousands of outbreaks have occurred affecting at least 320 species belonging to 21 orders, of which the vast majority are waterbirds. In this report we provide examples from across the globe associated with population level declines. Only Australia and Antarctica are unaffected, although this could change rapidly. Despite the carnage caused by mass mortality events, there are strategies to better protect waterbirds in both the short and long term. These include prevention of further spillover events from poultry, designing improved surveillance systems to both inform virus epidemiology and to benefit of all wild birds rather than only poultry (and humans), and respond appropriately to outbreaks in wildlife with necessary detail and resources. The loss of waterbirds at the current scale will not only be a conservation disaster, but also an ecological disaster, and therefore response to outbreaks in waterbirds must be prioritized.
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| 10. |
- Gast, Gerrie-Cor M, et al.
(författare)
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Menopausal Complaints Are Associated With Cardiovascular Risk Factors.
- 2008
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Ingår i: Hypertension. - 1524-4563. ; 51:6, s. 1492-1498
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Tidskriftsartikel (refereegranskat)abstract
- It has been hypothesized that women with vasomotor symptoms differ from those without with respect to cardiovascular risk factors or responses to exogenous hormone therapy. We studied whether the presence and extent of menopausal complaints are associated with cardiovascular risk profile. Data were used from a population-based sample of 5523 women, aged 46 to 57 years, enrolled between 1994 and 1995. Data on menopausal complaints and potential confounders were collected by questionnaires. Total cholesterol, systolic and diastolic blood pressures, and body mass index were measured. Linear and logistic regression analyses were used to analyze the data. Night sweats were reported by 38% and flushing by 39% of women. After multivariate adjustment, women with complaints of flushing had a 0.27-mmol/L (95% CI: 0.15 to 0.39) higher cholesterol level, a 0.60-kg/m(2) (95% CI: 0.35 to 0.84) higher BMI, a 1.59-mm Hg (95% CI: 0.52 to 2.67) higher systolic blood pressure, and a 1.09-mm Hg (95% CI: 0.48 to 1.69) higher diastolic blood pressure compared with asymptomatic women. Flushing was also associated with hypercholesterolemia (odds ratio: 1.52; 95% CI: 1.25 to 1.84) and hypertension (OR: 1.20; 95% CI: 1.07 to 1.34). Results were similar for complaints of night sweating. The findings support the view that menopausal complaints are associated with a less favorable cardiovascular risk profile. These findings substantiate the view that differences in the presence of menopausal symptoms as a reason for using hormone therapy could explain discrepant findings between observational research and trials.
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