nerogiga.blogg.se - Spotless starling

At the same time, these secondary nests were closer to the main nest than random distances within the colony, suggesting that access to public information was restricted to a narrow area around the main nest. Analyses of the distance between the main nest and nests containing the secondary polygynous brood or extra-pair or parasitic young showed an avoidance of contiguous nests for conducting these alternative reproductive tactics. We also found evidence of conspecific brood parasitism (CBP), by nesting females that laid part of the clutch in another nest or that after losing a partially laid clutch resorted to lay the last eggs in another nest. We interpret these patterns as a consequence of an increase of floaters with time these birds pursue a mixture of alternative mating strategies to succeed in the population. In parallel to this temporal change, we found an increase in intra-specific brood-parasitism and quasi-parasitism (QP). Parentage data from these years shows that polygyny decreased with time, likely as a consequence of increased competition for nesting sites and mates by new recruits, and immigrants of higher quality arriving to the colony as time passed. In this study, we examined the temporal plasticity of these strategies, following a population from the year of colony formation to 2 years after this. However, substantial variation at the species level suggests that ecological factors are important in shaping these patterns. Variation in avian reproductive strategies is often studied from a comparative perspective, since even closely-related taxa differ greatly in the degree of polygyny, extra-pair paternity (EPP) or intra-specific brood-parasitism. 3Departamento de Ecología Evolutiva, Museo Nacional de Ciencias Naturales (CSIC), Madrid, Spain.

2School of Biology, Harold Mitchell Building, University of St Andrews, St Andrews, United Kingdom.

1School of Life Sciences, Anglia Ruskin University, Cambridge, United Kingdom.

Female floaters were more frequently chased, probably because they regularly lay parasitically in conspecific nests.Patricia Celis 1*, Jeff A. Both sexes regularly attacked intruders, which implies that the intruders inflicted some kind of cost on the owners. However, the intrusion rates were higher when there were nestlings than during the incubation period, which suggests that collecting public information was also involved in the intruding behaviour. This finding supports the hypothesis that, in most cases, birds visited nests to obtain personal information about nesting resources. This result suggests that the presence of intruding males in the nests was affected by an increased opportunity to find vacancies in nesting territories as resident males became older. The proportion of the sexes among the intruders in each study year was correlated with the average age of male owners but not with the age of female owners. The average annual rate of intrusion of either sex was strongly correlated with the number of fledglings produced in the study colony the previous year, which seems to indicate that the inexperienced intruders were, in general, yearlings. The ratio of male‐to‐female intruders was higher among birds without previous breeding experience, although our results did not allow us to determine whether more inexperienced males or females intruded nests.

In a free‐ranging population of spotless starlings ( Sturnus unicolor), inexperienced birds were the predominant intruders. Although the relationship between the sex, age and breeding experience of intruders and the sex and age of residents may be crucial for understanding the significance of nest‐prospecting behaviour, a precise determination of these traits has rarely been addressed in field studies. The prospective behaviour for nests by conspecific intruders may be a strategy to gather public information for future reproduction or to secure resources for immediate reproduction. Polo, Vicente Arenas, Marta Sánchez, Sara Wright, J. Intruders in Nests of the Spotless Starling: Prospecting for Public Information or for Immediate Nesting Resources? Intruders in Nests of the Spotless Starling: Prospecting for Public Information or for Immediate.