Food availability and population processes: severity of nutritional stress during reproduction predicts survival of long‐lived seabirds

Abstract

Summary1. Life-history theory predicts a trade-off between costs of current reproduction and future survival of individuals. Studies of short-lived animals in general support this prediction. However, the effect of nutritional stress during reproduction on survival of long-lived animals is poorly understood. 2. We examined the link between nutritional stress, fecundity and return to a breeding colony (hereafter 'survival') of black-legged kittiwakes (Rissa tridactyla) at two colonies with contrasting patterns in adult survival, fecundity, and numerical trends. 3. We tested the observational (at Duck and Gull Is., Cook Inlet, Northern Gulf of Alaska) and experimental (at Middleton I., Gulf of Alaska) relationships between variations in the secretion of the stress hormone corticosterone (CORT) and food abundance. Then, we examined the relationships between nutritional stress (as reflected in CORT), reproduction, and survival of individuals. 4. On average, CORT was higher in kittiwakes breeding on Duck I. (declining, low fecundity, high survival) compared to those breeding on Gull I. (increasing, high fecundity, low survival). 5. At both colonies, CORT was directly negatively correlated with food abundance quantified at sea. Experimental feeding of individuals ad libitum resulted in a reduction of CORT in birds breeding on Middleton I. These results suggest that CORT is a reliable measure of food availability and defines nutritional stress (stress) in kittiwakes. 6. On Gull I., where survival is low (86%), production of young declined as stress increased. On Duck I., where survival is high (93%), parents always failed in raising young, though they experienced a wide range of stress levels. 7. Survival of individuals is linked to their CORT levels during reproduction. High levels of CORT predicted disappearance of individuals from both colonies. 8. The results support the hypothesis that nutritional stress during reproduction affects both survival and reproduction in long-lived animals. However, even within a species the ways in which survival and reproduction trade-off against each other may vary among populations. Results suggest that reproductive consequences of nutritional stress might differ between declining and increasing populations, which should be tested. We conclude that severity of nutritional stress during reproduction is one of the major factors defining population processes in kittiwakes.

Does location really matter? An inter-colony comparison of seabirds breeding at varying distances from productive oceanographic features in the Bering Sea

“…Our results support the flexible time budget hypothesis, with parents at both Pribilof Islands experiencing relatively poor foraging conditions, but maintaining similar chick-provisioning rates and fledging success by spending more time foraging than Bogoslof birds. However, this flexibility is not without its potential long-term costs, and high levels of CORT (Brown et al, 2005;Kitaysky et al 2007Kitaysky et al , 2010Romero and Wikelski, 2001), and increased parental effort (Golet et al, 1998) may be detrimental to adult survival. Although colony attendance differed among colonies by only 3 min h À 1 , this translates to an extra 48 min in a 16 h day diverted to foraging.…”

“…Levels have also been shown to be elevated during food shortages (Kitaysky et al, 1999a(Kitaysky et al, , 1999b, and in individuals in poor body condition (Kitaysky et al, 1999b;Romero and Wikelski, 2001; but see Schultner et al, 2013). Studies of seabirds have shown that the secretion of CORT is largely driven by changes in food (Benowitz-Fredericks et al, 2008;Kitaysky et al, 1999bKitaysky et al, , 2007Kitaysky et al, , 2010, and a strong negative correlation between CORT and fish abundance has been demonstrated in a number of seabird populations, including common murres (Uria aalge; Kitaysky et al, 2007). Baseline concentrations of CORT increase in a matter of days in response to food limitation 2010), and a number of seabird studies have used CORT as an index of the nutritional status of individuals (e.g., Dorresteijn et al, 2012;Satterthwaite et al, 2010;Schultner et al, 2013;Welcker et al, 2009).…”

The relationship between physiological stress and wildlife disease: consequences for health and conservation

“…Parallel glucocorticoid and infection parameters have been measured in few studies; however, these studies have included species ranging from the seahorse (Anderson et al 2011) to amphibians (Kindermann et al 2012;Gabor et al 2013), birds (Lindström et al 2005;Kitaysky et al 2010), lizards (Oppliger et al 1998) and non-human primates Clough et al 2010), indicating the potential of this method to be used in different taxa. This approach has been applied in a small number of stress and disease studies conducted on endangered species in challenging field conditions (Aguirre et al 1995;Chapman et al 2006).…”

Corticosterone Concentrations Reflect Parental Expenditure in Contrasting Mating Systems of Two Coucal Species

“…Typically, baseline corticosteronethe major glucocorticoid of birds and many other vertebrates-is elevated during the parental phase (reviewed by Romero, 2002) reflecting the increased energetic demands (and allostatic state) of parenting. As a consequence, corticosterone has frequently been considered a physiological correlate of parental resource allocation to offspring care (= parental expenditure sensu Smiseth et al, 2012; see e.g., Love et al, 2004;Kern et al, 2005;Angelier et al, 2007;Groscolas et al, 2008;Bonier et al, 2009b;Kitaysky et al, 2010;Ouyang et al, 2011;Crossin et al, 2012;Ouyang et al, 2013a;Villavicencio et al, 2014). If baseline corticosterone concentrations reflect parental expenditure, then individuals with a lower parental expenditure should express lower levels of the hormone than individuals with higher parental expenditure.…”