The number of breeding eiders at Christiansø and the amount of fertilizer used by Danish farmers (indexed as 1950 = 100) during 1925–2010.

<p>The number of breeding eiders at Christiansø and the amount of fertilizer used by Danish farmers (indexed as 1950 = 100) during 1925–2010.</p

Long-Term Changes in Nutrients and Mussel Stocks Are Related to Numbers of Breeding Eiders <i>Somateria mollissima</i> at a Large Baltic Colony

<div><p>Background</p><p>The Baltic/Wadden Sea eider <i>Somateria mollissima</i> flyway population is decreasing, and this trend is also reflected in the large eider colony at Christiansø situated in the Baltic Sea. This colony showed a 15-fold increase from 1925 until the mid-1990's, followed by a rapid decline in recent years, although the causes of this trend remain unknown. Most birds from the colony winter in the Wadden Sea, from which environmental data and information on the size of the main diet, the mussel <i>Mytilus edulis</i> stock exists. We hypothesised that changes in nutrients and water temperature in the Wadden Sea had an effect on the ecosystem affecting the size of mussel stocks, the principal food item for eiders, thereby influencing the number of breeding eider in the Christiansø colony.</p><p>Methodology/Principal Finding</p><p>A positive relationship between the amount of fertilizer used by farmers and the concentration of phosphorus in the Wadden Sea (with a time lag of one year) allowed analysis of the predictions concerning effects of nutrients for the period 1925–2010. There was (1) increasing amounts of fertilizer used in agriculture and this increased the amount of nutrients in the marine environment thereby increasing the mussel stocks in the Wadden Sea. (2) The number of eiders at Christiansø increased when the amount of fertilizer increased. Finally (3) the number of eiders in the colony at Christiansø increased with the amount of mussel stocks in the Wadden Sea.</p><p>Conclusions/Significance</p><p>The trend in the number of eiders at Christiansø is representative for the entire flyway population, and since nutrient reduction in the marine environment occurs in most parts of Northwest Europe, we hypothesize that this environmental candidate parameter is involved in the overall regulation of the Baltic/Wadden Sea eider population during recent decades.</p></div

ESM Table 1 from Brain size in birds is related to traffic accidents

Probability of birds being killed by traffic in relation to residual brain mass (covariate), age, sex and species (random factor) across all species of birds after exclusion of specimens that were shot

The number of breeding eiders at Christiansø in year (i) in relation to mussel stocks (metric tonnes) the same year (year (i)).

<p>The number of breeding eiders at Christiansø in year (i) in relation to mussel stocks (metric tonnes) the same year (year (i)).</p

Eiders breeding at Christiansø are wintering in the Wadden Sea (toned brown) and in Kattegat.

<p>The eider colony at Christiansø in the Southern Baltic Sea was one of the largest colonies in the Baltic/Wadden Sea flyway population during the mid-1990's.</p

Elevated Frequency of Cataracts in Birds from Chernobyl

<div><p>Background</p><p>Radiation cataracts develop as a consequence of the effects of ionizing radiation on the development of the lens of the eye with an opaque lens reducing or eliminating the ability to see. Therefore, we would expect cataracts to be associated with reduced fitness in free-living animals.</p><p>Methodology/Principal Findings</p><p>We investigated the incidence of lens opacities typical of cataracts in more than 1100 free-living birds in the Chernobyl region in relation to background radiation. The incidence of cataracts increased with level of background radiation both in analyses based on a dichotomous score and in analyses of continuous scores of intensity of cataracts. The odds ratio per unit change in the regressor was 0.722 (95% CI 0.648, 0.804), which was less than odds ratios from investigations of radiation cataracts in humans. The relatively small odds ratio may be due to increased mortality in birds with cataracts. We found a stronger negative relationship between bird abundance and background radiation when the frequency of cataracts was higher, but also a direct effect of radiation on abundance, suggesting that radiation indirectly affects abundance negatively through an increase in the frequency of cataracts in bird populations, but also through direct effects of radiation on other diseases, food abundance and interactions with other species. There was no increase in incidence of cataracts with increasing age, suggesting that yearlings and older individuals were similarly affected as is typical of radiation cataract.</p><p>Conclusions/Significance</p><p>These findings suggest that cataracts are an under-estimated cause of morbidity in free-living birds and, by inference, other vertebrates in areas contaminated with radioactive materials.</p></div

Number of breeding eiders at Christiansø in year (i) in relation to fertilizer use in Danish agriculture in the same year (year (i)) (1950 = 100).

<p>Number of breeding eiders at Christiansø in year (i) in relation to fertilizer use in Danish agriculture in the same year (year (i)) (1950 = 100).</p

Total concentration of phosphate (µg/l) in the Danish Wadden Sea in year (i) in relation to fertilizer use in agriculture (1950 = 100) in the previous year (year (i-1)).

<p>Total concentration of phosphate (µg/l) in the Danish Wadden Sea in year (i) in relation to fertilizer use in agriculture (1950 = 100) in the previous year (year (i-1)).</p

Mean cataracts in birds from Chernobyl in relation to background radiation level (μSv/h).

<p>The linear fit with confidence intervals is shown.</p

Appendix A. A table presenting information on predation risk, body mass, nest site, breeding sociality, sexual dichromatism, sexual size dimorphism, population density, prevalence of four genera of blood parasites, overall prevalence of blood parasites, and number of individuals examined for blood parasites for prey of Goshawk and Sparrowhawk.

A table presenting information on predation risk, body mass, nest site, breeding sociality, sexual dichromatism, sexual size dimorphism, population density, prevalence of four genera of blood parasites, overall prevalence of blood parasites, and number of individuals examined for blood parasites for prey of Goshawk and Sparrowhawk