Impacts of extreme climatic events on the energetics of long-lived vertebrates: the case of the greater flamingo facing cold spells in the Camargue

Abstract

Most studies analyzing the effects of global warming on wild populations focus on gradual temperature changes, yet it is also important to understand the impact of extreme climatic events. Here we studied the effect of two cold spells (January 1985 and February 2012) on the energetics of greater flamingos (Phoenicopterus roseus) in the Camargue (southern France). To understand the cause of observed flamingo mass mortalities, we first assessed the energy stores of flamingos found dead in February 2012, and compared them with those found in other bird species exposed to cold spells and/or fasting. Second, we evaluated the monthly energy requirements of flamingos across 1980-2012 using the mechanistic model Niche Mapper TM . Our results show that the body lipids of flamingos found dead in 2012 corresponded to 2.6±0.3% of total body mass, which is close to results found in woodcocks (Scolopax rusticola) that died from starvation during a cold spell (1.7±0.1%), and much lower than in woodcocks which were fed throughout this same cold spell (13.0±2%). Further, Niche Mapper TM predicted that flamingo energy requirements were highest (+6-7%) during the 1985 and 2012 cold spells compared with 'normal' winters. This increase was primarily driven by cold air temperatures. Overall, our findings strongly suggest that flamingos starved to death during both cold spells. This study demonstrates the relevance of using mechanistic energetics modelling and body condition analyses to understand and predict the impact of extreme climatic events on animal energy balance and winter survival probabilities.

Effects of extreme weather on two sympatric Australian passerine bird species

“…Cold exposure can cause mortality of small passerines in winter, even in conditions that are relatively mild [17,22,44]. For example, prolonged exposure to cold wet weather with daily minima less than 58C was associated with high mortality in a range of similar-sized passerine species in Britain [23].…”

Associations between changing climate and body condition over decades in two southern hemisphere passerine birds

“…Extreme cold events can also have similar fitness consequences. For example, greater flamingos, Phoenicopterus roseus, with lower body condition experienced mass starvation under the combined effect of lower than average winter temperatures and a cold spell that limited access to food [9].…”

Factors influencing mobility and survival of Eurasian Woodcock wintering in Spain

“…With low temperatures, nonhibernating endotherms are confronted with increasing energy requirements to enhance thermogenesis while food is a scarce resource (Boos et al 2007, Deville et al 2014. In many bird species it has thus been shown that winter conditions such as low temperatures or consecutive frosts influence survival (e.g., Deville et al 2014, Johnston et al 2016.…”

“…With low temperatures, nonhibernating endotherms are confronted with increasing energy requirements to enhance thermogenesis while food is a scarce resource (Boos et al 2007, Deville et al 2014. In many bird species it has thus been shown that winter conditions such as low temperatures or consecutive frosts influence survival (e.g., Deville et al 2014, Johnston et al 2016. In France, a negative relationship between winter temperature and woodcock survival was also found, as well as escape behavior below a certain temperature threshold (Tavecchia et al 2002, Péron et al 2011a, presumably because dealing with such conditions would be riskier than moving away from their usual wintering areas (Duriez 2003).…”