Seasonal weather effects on the common eider, a subarctic capital breeder, in Iceland over 55 years

Abstract

Changes in bird populations and their phenology (i.e. timing of nesting and migration) are increasingly linked to global climatic changes, particularly at temperate and Arctic latitudes. These patterns arise from local-and regional-scale effects of weather on demography but long-term time-series data necessary to explore these relationships are rarely available. Colonies of the common eider Somateria mollissima are often monitored annually for nest-down harvesting. We use long-term data from 2 nesting colonies in northwest Iceland (Bíldsey, Brei7afjör7ur: 29 yr and Laekur, Dýrafjör7ur: 55 yr) to examine the effects of weather conditions in each season on breeding numbers, arrival dates and clutch sizes. Numbers of nests in Bíldsey increased following warm, wet winters and first nests were produced later following windy and wet winters at Laekur. In spring, windy conditions tended to be followed by earlier female arrivals at Bíldsey. Warm, wet springs were positively correlated with larger clutch sizes at Laekur, and clutch sizes at Laekur decreased following especially wet and warm autumns. The overall population trends vary among sites and are likely to be influenced by both climatic and management conditions. These findings indicate that the effects of global climatic changes will depend on the details of changes in local weather conditions within each season. The strong effects on nesting dates and clutch sizes suggest that accumulation of body reserves, which sustain females during incubation and into brood rearing, is a key mechanism that could determine how altered distribution and frequencies of depressions within each season will affect future numbers of this species.KEY WORDS: Climate · Phenology · Temperature · Winter harshness · Breeding · Arctic · Waterfowl · Capital breeder Resale or republication not permitted without written consent of the publisherClim Res 38: [237][238][239][240][241][242][243][244][245][246][247][248] 2009 Arctic latitudes (66°N and higher), the short summer predisposes birds to complete breeding in a particularly short time (Poussart et al. 2000). A number of studies have shown how initiation of breeding is related to trends in climatic change, particularly through earlier spring migration and subsequent initiation of breeding (Durant et al. 2004, Frederiksen et al. 2004, Sparks et al. 2005, Jonzen et al. 2006, see also Robinson et al. 2007 and citations therein).Early nesters are generally individuals in relatively good body condition, which often consequently lay the largest clutches and attain the highest breeding success (Erikstad et al. 1993, Arnold et al. 2004, Bêty et al. 2004. Clutch size correlates with body condition in Arctic-breeding geese (genera Anser, Chen and Branta) and in ducks such as the common eider Somateria mollissima (Ankney & MacInnes 1978, Erikstad et al. 1993, Öst et al. 2008. Many birds exhibit a seasonal decline in clutch size (Arnold et al. 2004) and chick survival may decrease with advanced hatching date (Traylor & Alisauskas 2006)...

Nesting Common Eider (<i>Somateria mollissima</i>) Population Quintuples in Northwest Greenland

“…Additionally, mean annual ambient temperature has increased significantly since the 1980s (Born et al, 2011;Burnham et al, 2012). An ameliorating climate has been shown to be beneficial for eiders by increasing annual productivity (Lehikoinen et al, 2006;Jónsson et al, 2009) Melhum (2012) showed that early breakup of sea ice in the Kongsfjorden area of Svalbard was associated with more nests and larger average clutch sizes, at both regional and individual island levels. In Baffin Bay, which includes the Avanersuaq District, Stirling and Parkinson (2006) showed that sea ice breakup occurred approximately six to seven days earlier in each decade from 1979 to 2004.…”

Trends and population dynamics of a Velvet Scoter (Melanitta fusca) population: influence of density dependence and winter climate

“…In a study of eiders on Island, breeding numbers were 523 significantly correlated to local winter weather conditions but not to winter 524 NAO-index, although winter weather conditions were significantly correlated 525 with winter NAO-index (Jónsson et al 2009). This implies that winter 526 weather conditions might have an even larger effect on the variation in 527 breeding numbers of velvet scoters at Åland, than suggested by our results.…”

The early birds and the rest: do first nesters represent the entire colony?

“…Like other seaducks (Mergini), common eider spring arrival responded to local weather parameters, ice cover, the North Atlantic Oscillation (NAO) index and fertilizer release Jónsson et al 2009;Love et al 2010;Zipkin et al 2010;Laursen and Møller 2014). In northwest Iceland, spring icecover generally is absent but females arrived later following warm winters with strong westerly winds (positive NAO values; Jónsson et al 2009), whereas females in southwest Iceland nested earlier following milder winters (D'Alba et al 2010).…”

“…Common eider responds to climate change because females that attain the best body condition in late winter generally become the first nesters in a given year (Bolduc et al 2005;Ö st et al 2008) and earlier nesting generally is positively related to hatching success (Ö st et al 2011), more exogenous protein use for egg formation relative to later nesters (Sénéchal et al 2011), and increased clutch sizes Jónsson et al 2009;Mehlum 2012). Unfavorable winter weather can interfere with accumulation of endogenous reserves for breeding, cause nest desertion and affect levels of yolk hormone, nest site selection or immune function (Robertson 1995;Descamps et al 2010;Love et al 2010;Sénéchal et al 2010;Jónsson and Lúðvíksson 2013).…”