Predicting reproductive success from hormone concentrations in the common tern (Sterna hirundo) while considering food abundance

Abstract

In birds, reproductive success is mainly a function of skill or environmental conditions, but it can also be linked to hormone concentrations due to their effect on behavior and individual decisions made during reproduction. For example, a high prolactin concentration is required to express parental behaviors such as incubation or guarding and feeding the young. Corticosterone level, on the other hand, is related to energy allocation or stress and foraging or provisioning effort. In this study, we measured individual baseline prolactin and corticosterone between 2006 and 2012 in breeding common terns (Sterna hirundo) using blood-sucking bugs. Reproductive parameters as well as prey abundance on a local and a wider scale were also determined during this period. Baseline prolactin and corticosterone varied significantly between years, as did breeding success. At the individual level, prolactin was positively and corticosterone was negatively linked to herring and sprat abundance. At the population level, we also found a negative link between corticosterone and prey abundance, probably reflecting overall foraging conditions. High prolactin during incubation was mainly predictive of increased hatching success, potentially by supporting more constant incubation and nest-guarding behavior. It was also positively linked to a lesser extent with fledging success, which could indicate a high feeding rate of young. Corticosterone concentration was positively related to high breeding success, which may be due to increased foraging activity and feeding of young. In general, our study shows that baseline prolactin and corticosterone levels during incubation can predict reproductive success, despite the presence of an interval between sampling and hatching or fledging of young.

What makes a good parent? Sex-specific relationships between nest attendance, hormone levels, and breeding success in a long-lived seabird

“…Other studies of seabirds have found clear effects of year on reproductive success (e.g., Becker 1998, Quilllfeldt 2001, Golet et al 2004) and, in a previous study, we also showed that reproductive success was significantly different between years in this Common Tern colony (Riechert et al 2014a). However, sample sizes were much higher in these studies.…”

“…There have been a number of studies conducted in this colony specifically to investigate the influence of hormones on behavior and reproductive success, which form a basis for this work. Riechert et al (2014a) showed that prolactin levels increased with breeding experience in young Common Terns, which was correlated with improved success during initial breeding attempts. Overall, increased reproductive output was linked with high prolactin levels and slightly increased baseline corticosterone, especially in males (Riechert et al 2014a).…”

“…Riechert et al (2014a) showed that prolactin levels increased with breeding experience in young Common Terns, which was correlated with improved success during initial breeding attempts. Overall, increased reproductive output was linked with high prolactin levels and slightly increased baseline corticosterone, especially in males (Riechert et al 2014a). Due to their small body reserves and longevity, sufficient body condition of parents is crucial for breeding behavior: During long fasting bouts on the nest, prolactin decreases while corticosterone increases (Riechert et al 2014b), a combination that may lead to nest abandonment (Spée et al 2010(Spée et al , 2011.…”

“…Parental attendance at the nest was quite variable between Common Tern pairs; however, interpair variability was not related to hatching success or incubation duration. Though linked to parental quality (Wendeln and Becker 1999a), hatching success in the Banter See colony was relatively high overall during the years of this study (Riechert et al 2014a). This could be one reason for no link being found with nest attendance.…”

Does prolactin mediate parental and life-history decisions in response to environmental conditions in birds? A review

“…To our knowledge, only three studies have examined the relationship between circulating prolactin and environmental conditions in parent birds. First, Riechert et al (2014a) found that prolactin levels were not correlated with food abundance in Common terns although prolactin titers were particularly low during two years of low food availability. Second, Leclaire et al (2011) found that prolactin levels were not affected by an experimental handicap (i.e.…”