Grit ingestion and size-related consumption of tubers by Graylag Geese

In herbivorous birds the processing rate of food is constrained by gizzard capacity. To enhance digestive processes, many species ingest grit to grind the food. Grit ingestion, however, may further limit the capacity of file gizzard. Graylag Geese (Anser anser) wintering in SW Spain fed mainly on Alkali Bulrush (Scirpus maritimus) tubers, showing a preference for small tubers. This preference may be due to a faster disintegration of small tubers than larger ones inside the gizzard. As larger tubers are likely coarser than smaller tubers, more grit would be necessary to process larger tubers. However, the ingestion of more grit to grind large tubers would be at the expense of ingesting additional tubers because of gizzard capacity limitations. Under these circumstances, there may be an inverse relationship between tuber size and amount of grit ingested to optimize food ingestion. Indeed, we found such a relationship. Grit facilitated the disintegration of tubers. This suggests that relying on some amount of grit to facilitate the grinding of food should outweigh the loss of gizzard capacity to the amount of food ingested.Peer Reviewe

The role of parasites in the invasion success of the exotic brine shrimp Artemia Franciscana in the Meditarranean region

Trabajo presentado en el Symposium for European Freshwater Science, celebardo en Girona del 27 de junio al 1 de julio de 2011.Biological invasions are main threats to biodiversity at global scale and increasing numbers of studies suggest that parasites may have a role. However, the mechanism through which parasites may influence the outcome of the invasion is poorly understood. Here we provide evidence supporting the role of parasites as potential agents mediating the competitive exclusion of Mediterranean brine shrimps Artemia (A. parthenogenetica and A. salina) by the exotic American A. franciscana, using different native and invasive populations from South Spain and South France. Our results revealed high rates of infection by cestodes in native brine shrimps, sometimes with extreme prevalences of up to 100%. In contrast, A. franciscana populations showed very low diversity, prevalence and burden of cestodes. The effect of parasites in native populations was multiple, ranging from reproduction and survival, to life history traits, microhabitat selection and diet. Infection strongly reduced host fitness by both, reducing fecundity (parasite castration) and indirectly increasing predation by birds final hosts as revealed by prey choice experiments. We found evidence that high rate of parasitism (particularly the castrating parasite Flamingolepis liguloides, the most prevalent cestode in natives but nearly absent in the exotic Artemia), indirectly affected the life-history strategy of non infected individuals, inducing for example earlier maturation. Moreover cestodes influenced spatial (vertical and horizontal) distribution of the host, altering the diet as revealed by isotopic analysis. Contrasting with the strong impact of parasites in native populations, we have never observed any pathology (castration, behavioural alteration, etc) associated with infection in the exotic species. Overall, the results of this study suggest that the large impact of cestode on the native, but not the invading species, is likely to confer a decisive competitive advantage to the invader, contributing to explain the demographic success of A. franciscana in the Mediterranean region.Peer reviewe

Cardiovascular disease, chronic kidney disease, and diabetes mortality burden of cardiometabolic risk factors from 1980 to 2010: A comparative risk assessment

Background: High blood pressure, blood glucose, serum cholesterol, and BMI are risk factors for cardiovascular diseases and some of these factors also increase the risk of chronic kidney disease and diabetes. We estimated mortality from cardiovascular diseases, chronic kidney disease, and diabetes that was attributable to these four cardiometabolic risk factors for all countries and regions from 1980 to 2010. Methods: We used data for exposure to risk factors by country, age group, and sex from pooled analyses of population-based health surveys. We obtained relative risks for the effects of risk factors on cause-specific mortality from meta-analyses of large prospective studies. We calculated the population attributable fractions for each risk factor alone, and for the combination of all risk factors, accounting for multicausality and for mediation of the effects of BMI by the other three risks. We calculated attributable deaths by multiplying the cause-specific population attributable fractions by the number of disease-specific deaths. We obtained cause-specific mortality from the Global Burden of Diseases, Injuries, and Risk Factors 2010 Study. We propagated the uncertainties of all the inputs to the final estimates. Findings: In 2010, high blood pressure was the leading risk factor for deaths due to cardiovascular diseases, chronic kidney disease, and diabetes in every region, causing more than 40% of worldwide deaths from these diseases; high BMI and glucose were each responsible for about 15% of deaths, and high cholesterol for more than 10%. After accounting for multicausality, 63% (10·8 million deaths, 95% CI 10·1-11·5) of deaths from these diseases in 2010 were attributable to the combined effect of these four metabolic risk factors, compared with 67% (7·1 million deaths, 6·6-7·6) in 1980. The mortality burden of high BMI and glucose nearly doubled from 1980 to 2010. At the country level, age-standardised death rates from these diseases attributable to the combined effects of these four risk factors surpassed 925 deaths per 100 000 for men in Belarus, Kazakhstan, and Mongolia, but were less than 130 deaths per 100 000 for women and less than 200 for men in some high-income countries including Australia, Canada, France, Japan, the Netherlands, Singapore, South Korea, and Spain. Interpretation: The salient features of the cardiometabolic disease and risk factor epidemic at the beginning of the 21st century are high blood pressure and an increasing effect of obesity and diabetes. The mortality burden of cardiometabolic risk factors has shifted from high-income to low-income and middle-income countries. Lowering cardiometabolic risks through dietary, behavioural, and pharmacological interventions should be a part of the global response to non-communicable diseases. Funding: UK Medical Research Council, US National Institutes of Health. © 2014 Elsevier Ltd

Breeding biology of two sympatric coots with contrasting conservation status

Capsule: Red-knobbed Coots Fulica cristata and Common Coots Fulica atra have similar breeding biology except in chick survival, which was significantly lower in Red-knobbed Coots. Aims: To provide information on the breeding biology of Red-knobbed Coots in Spain and to compare this with similar data for Common Coots. Methods: During two consecutive breeding seasons, clutch size, egg size, brood size and chick survival of Red-knobbed and Common Coots were studied in nearly all of the lagoons in which Red-knobbed Coots were breeding. Results: Clutch size was similar in the two species. Egg volume varied between years within species. Both species had similar brood sizes but chick survival differed significantly, being lower in Red-knobbed Coots (36% and 55% in 2002 and 2003, respectively) than in Common Coots (93% and 91% in 2002 and 2003, respectively). The number of fledglings per pair was lower in Red-knobbed Coots (0.9 and 2.1 in 2002 and 2003, respectively) than in Common Coots (2.2 and 3.0 in 2002 and 2003, respectively). Conclusion: The disparity in productivity between Red-knobbed and Common Coots in the lagoons of southern Spain is mainly due to differential chick survival rates. These differences could be the key factor that has led to their currently different conservation status in Spain. © 2008 British Trust for Ornithology.Peer Reviewe

Differences in food assimilation between two coot species assessed with stable isotopes and particle size in faeces: Linking physiology and conservation

The red-knobbed coot Fulica cristata experienced a dramatic population decline in Spain, where the common coot F. atra does not face conservation problems. This is puzzling because both species have similar ecologies. It has been suggested that habitat alterations affected the quality of food plants, and this impacted differentially both coots. To verify this, we conducted experiments to determine the assimilation efficiency of both species in relation to food quality. Two types of diets differing in fibre content (commercial food and Potamogeton pectinatus) were offered to captive red-knobbed and common coots, during both spring and autumn. We examined variations in faecal particle size among coot species and diets, indicative of the facility with which food can be assimilated, and used the stable isotope technique to study differences between coot species in stable isotope fractionations from consumption to excretion. Faecal particle size was larger in red-knobbed than in common coots when fibre content was high, but was similar when it was low. Faecal particle sizes were larger in autumn, when fibre content was higher, than in spring. In general, δ15N in faeces of red-knobbed coots was greater than in faeces of common coots. These results suggest that the digestive efficiency of the red-knobbed coot was lower than that of the common coot, and that the differences increased when the fibre content in food plants increased. Managers should try to make available to coots wetland habitat with high quality food, which may be facilitated by prolonging the hydroperiods. © 2007 Elsevier Inc. All rights reserved.Peer Reviewe

Breeding biology of two sympatric coots with contrasting conservation status: Capsule Red-knobbed Coots Fulica cristata and Common Coots Fulica atra have similar breeding biology except in chick survival, which was significantly lower in Red-knobbed Coots

7 pages.[Aims] To provide information on the breeding biology of Red-knobbed Coots in Spain and to compare this with similar data for Common Coots.[Methods] During two consecutive breeding seasons, clutch size, egg size, brood size and chick survival of Red-knobbed and Common Coots were studied in nearly all of the lagoons in which Red-knobbed Coots were breeding.[Results] Clutch size was similar in the two species. Egg volume varied between years within species. Both species had similar brood sizes but chick survival differed significantly, being lower in Red-knobbed Coots (36% and 55% in 2002 and 2003, respectively) than in Common Coots (93% and 91% in 2002 and 2003, respectively). The number of fledglings per pair was lower in Red-knobbed Coots (0.9 and 2.1 in 2002 and 2003, respectively) than in Common Coots (2.2 and 3.0 in 2002 and 2003, respectively).[Conslusion] The disparity in productivity between Red-knobbed and Common Coots in the lagoons of southern Spain is mainly due to differential chick survival rates. These differences could be the key factor that has led to their currently different conservation status in Spain.Peer reviewe

White Wagtails Motacilla alba showing extensive post-juvenile moult are more stressed

Young individuals of many passerines undergo a partial moult and replace most of their body feathers and a variable number of coverts and minor wing feathers. In many species, this moult generates perceptible coloration differences, which may act as status signals. This study analyses how the extent of partial moult is related to different estimators of condition. A total of 43 young White Wagtails Motacilla alba caught in an urban roost in the city of Seville were analysed. The extent of their partial moult was positively correlated to the heterophil-lymphocyte ratio, but not to the abundance of leukocytes or to body mass. Individuals with more adult-like plumage may be exposed to higher stress due to the aggressiveness of territorial adults. Consequently, the increased heterophil-lymphocyte ratio found in the study is probably a consequence of the extent of moult rather than an explanation of intraspecific variation in the extent of moult.Peer reviewe

Habitat-related differences in foraging behaviour between sympatric Red-knobbed Coot (Fulica cristata) and European Coot (Fulica atra) in Morocco.

Peer Reviewe