Climate Change Increases Reproductive Failure in Magellanic Penguins

Abstract

Climate change is causing more frequent and intense storms, and climate models predict this trend will continue, potentially affecting wildlife populations. Since 1960 the number of days with >20 mm of rain increased near Punta Tombo, Argentina. Between 1983 and 2010 we followed 3496 known-age Magellanic penguin (Spheniscus magellanicus) chicks at Punta Tombo to determine how weather impacted their survival. In two years, rain was the most common cause of death killing 50% and 43% of chicks. In 26 years starvation killed the most chicks. Starvation and predation were present in all years. Chicks died in storms in 13 of 28 years and in 16 of 233 storms. Storm mortality was additive; there was no relationship between the number of chicks killed in storms and the numbers that starved (P = 0.75) or that were eaten (P = 0.39). However, when more chicks died in storms, fewer chicks fledged (P = 0.05, R 2 = 0.14). More chicks died when rainfall was higher and air temperature lower. Most chicks died from storms when they were 9–23 days old; the oldest chick killed in a storm was 41 days old. Storms with heavier rainfall killed older chicks as well as more chicks. Chicks up to 70 days old were killed by heat. Burrow nests mitigated storm mortality (N = 1063). The age span of chicks in the colony at any given time increased because the synchrony of egg laying decreased since 1983, lengthening the time when chicks are vulnerable to storms. Climate change that increases the frequency and intensity of storms results in more reproductive failure of Magellanic penguins, a pattern likely to apply to many species breeding in the region. Climate variability has already lowered reproductive success of Magellanic penguins and is likely undermining the resilience of many other species.

Large-scale climate and local weather drive interannual variability in Adélie penguin chick fledging mass

“…Although precipitation was not a key predictor variable in our models, it can cause the plumage of chicks to become damp or wet and is generally a major factor causing egg and chick mortality and slow growth due to hypothermia (Konarzewski & Taylor 1989, Thyen & Becker 2006. For example, Boersma & Rebstock (2014) found more chicks died when rainfall was high and air temperature was low. Wetness decreases the insulating properties of feathers, and this disruption likely increases heat loss (McCafferty et al 1997, Wilson et al 2004).…”

Natural selection on morphology varies among years and by sex in Magellanic Penguins (Spheniscus magellanicus)

“…We used the proportion of chicks that starved as a proxy for food availability and foraging success (Boersma and Stokes 1995). Data on both the number of chicks starved in each year and the total number of chicks came from Boersma and Rebstock (2014), who showed that~40% of chick deaths each year are due to starvation.…”

The ecological value of long-term studies of birds and mammals in Central America, South America and Antarctica

“…Using data from 1983 to 2010, [78] determined that starvation and predation were the most important predictors of chick mortality across years in Magellanic penguins, although climate variability also negatively influenced reproductive success. The number of storms in early December, when all chicks are less than 30 days of age, increased during the period of this study.…”