Our results showed that rats only managed to prey on intact eggs when these were small (canary) and that they had great difficulty preying on medium-sized (hen) and even small (quail)-sized intact eggs, selleck products regardless of the rat’ body
mass, gender and habitat. Conversely, rats preyed extensively on previously damaged eggs of all sizes. Our findings suggest that preying on intact bird eggs without specific learning skills, such as rolling an egg to break it, may be challenging for the black rats. Moreover, our findings strongly indicate that bird susceptibility to egg predation by rats varies with island contexts and may depend on a combination of multiple additive and synergic factors. Experiments that allow for testing the multiple evolutionary and ecological factors explaining between-island or between-population variation in rodent impacts are needed to promote a better overview of the processes involved in bird population declines. “
“Many tropical ecosystems support exceptional levels of amphibian diversity, but in contrast to their temperate counterparts, selleck inhibitor many aspects of their biology are little studied and poorly
understood. Demographic studies give valuable insights into the age structure and life histories of amphibian populations, thus they are of high importance in making accurate and precise conservation assessments in the light of current global Ureohydrolase amphibian declines. We analysed age structure and growth in a population
of the viviparous caecilian Geotrypetes seraphini, a caecilian amphibian from Mount Cameroon, Central Africa, by using skeletochronology. We detected lines of arrested growth (LAG) in mid-body vertebrae and interpreted them as indicators of a seasonal growth pattern. We expect that LAG are materialized at a rate of one per year. In our sample male reach sexual maturity at an early age (age class 0+), whereas females mature later (age class 1+). Maximum longevity in our sample was estimated at 4+ years. Body size (total length) was significantly smaller in males than in females. Our study shows that skeletochronology is a highly suitable method to determine caecilian growth and age. Caecilian amphibians show a high diversity of reproductive modes including unusual brood care and parental investment strategies. In order to deepen our understanding of their ecology and evolution, many more demographic studies on other species and lineages are needed. “
“Factors that affect group sizes in large ungulates are generally poorly understood for species from remote regions. Understanding grouping patterns is important for effective species management, but is lacking for the endangered Mongolian saiga (Saiga tatarica mongolica). We studied seasonal changes in the group size and social structure of saigas in relation to environmental and anthropogenic factors in western Mongolia during 2009–2012.