Masting, the highly variable production of synchronized large seed crops, is a common reproductive strategy in plant populations. In wind-pollinated trees, flowering and pollination dynamics are hypothesized to provide the mechanistic link for the well-known relationship between weather and population-level seed production. Several hypotheses make predictions about the effect of weather on annual pollination success. The pollen coupling hypothesis predicts that weather and plant resources drive the flowering effort of trees, which directly translates into the size of seed crops through efficient pollination. In contrast, the pollination Moran effect hypothesis predicts that weather affects pollination efficiency, leading to occasional bumper crops. Furthermore, the recently formulated phenology synchrony hypothesis predicts that Moran effects can arise because of weather effects on flowering synchrony, which, in turn, drives pollination efficiency. We investigated the relationship between weather, airborne pollen, and seed production in common European trees, two oak species (Quercus petraea and Q. robur) and beech (Fagus sylvatica) with a 19-yr data set from three sites in Poland. Our results show that warm summers preceding flowering correlated with high pollen abundance and warm springs resulted in short pollen seasons (i.e., high flowering synchrony) for all three species. Pollen abundance was the best predictor for seed crops in beech, as predicted under pollen coupling. In oaks, short pollen seasons, rather than pollen abundance, correlated with large seed crops, providing support for the pollination Moran effect and phenology synchrony hypotheses. Fundamentally different mechanisms may therefore drive masting in species of the family Fagacae.

Masting—temporally variable seed production with high spatial synchrony—is a pervasive strategy in wind‐pollinated trees that is hypothesized to be vulnerable to climate change due to its correlation with variability in abiotic conditions. Recent work suggests that aging may also have strong effects on seed production patterns of trees, but this potential confounding factor has not been considered in previous times series analysis of climate change effects. Using a 54 year dataset for seven dominant species in 17 forests across Poland, we used the proportion of seed‐producing trees (PST) to contrast the predictions of the climate change and aging hypotheses in Abies alba, Fagus sylvatica, Larix decidua, Picea abies, Pinus sylvestris, Quercus petraea, and Quercus robur. Our results show that in all species, PST increased over time and that this change correlated most strongly with stand age, while the standardized precipitation–evapotranspiration index, a measure of drought, contributed to temporal trends in PST of F. sylvatica and Q. robur. Temporal variability of PST also increased over time in all species except P. sylvestris, while trends in temporal autocorrelation and among‐stand synchrony reflect species‐specific masting strategies. Our results suggest a pivotal role of plant ontogeny in driving not only the extent but also variability and synchrony of reproduction in temperate forest trees. In a time of increasing forest regrowth in Europe, we therefore call for increased attention to demographic effects such as aging on plant reproductive behavior, particularly in studies examining global change effects using long‐term time series data.

Annually variable and synchronous seed production by plant populations, or masting, is a widespread reproductive strategy in long-lived plants. Masting is thought to be selectively beneficial because interannual variability and synchrony increase the fitness of plants through economies of scale that decrease the cost of reproduction per surviving offspring. Predator satiation is believed to be a key economy of scale, but whether it can drive phenotypic evolution for masting in plants has been rarely explored. We used data from seven plant species (Quercus humilis, Quercus ilex, Quercus rubra, Quercus alba, Quercus montana, Sorbus aucuparia and Pinus pinea) to determine whether predispersal seed predation selects for plant phenotypes that mast. Predation selected for interannual variability in Mediterranean oaks (Q. humilis and Q. ilex), for synchrony in Q. rubra, and for both interannual variability and reproductive synchrony in S. aucuparia and P. pinea. Predation never selected for negative temporal autocorrelation of seed production. Predation by invertebrates appears to select for only some aspects of masting, most importantly high coefficient of variation, supporting individual-level benefits of the population-level phenomenon of mast seeding. Determining the selective benefits of masting is complex because of interactions with other seed predators, which may impose contradictory selective pressures.

Social information use in songbird habitat selection commonly involves a conspecifi c attraction strategy. Individuals copy the breeding-site choices of conspecifi cs, that is, bias their own settlement decisions towards sites (tracts of spatially limited habitat with similar structure) already occupied by others. In order to be adaptive, social information use has to be discriminative. Especially the decisions of good quality individuals, i.e. measuring high at observable fi tness correlates, should be copied more frequently than those of poor quality individuals. It is unknown, however, whether songbirds discriminatively use conspecifi c presence by evaluating the quality of information providers in habitat selection. We experimentally tested whether wood warblers Phylloscopus sibilatrix selectively copied settlement decisions of conspecifi cs in relation to the quality of observed individuals. We also tested whether the use of social cues was infl uenced by the population density at a particular site in the preceding year. We found that wood warblers selectively used intraspecifi c social information, but in a pattern opposite to that expected based on existing hypotheses. Wood warblers copied breeding-site choices of poor quality conspecifi cs and despite temporary attraction to sites where the presence of good quality individuals was simulated, they did not ultimately settle near these individuals. Population density in the preceding year did not infl uence settlement patterns. We argue that when making settlement decisions, wood warblers assessed the expected level of local intraspecifi c competition and selectively copied breeding-site choices of conspecifi cs or refused to settle, depending on competitive abilities of observed individuals. Th is adds a novel aspect to the patterns and processes of social information use proposed thus far, and provides support for the predicted negative eff ect of intraspecifi c competition on benefi t of information. Moreover, it seems that habitat selection in wood warblers is a complex decision-making process, in which initial decisions are adjusted after acquiring more accurate information.Breeding-site selection decisions have important fi tness consequences. Th rough their eff ects on survival, mating opportunities and reproductive success these decisions are crucial to a species ' life-history (Cody 1985). Breeding habitats are spatio-temporally variable; hence individuals need to acquire information about potential breeding sites to make optimal settlement decisions. Environmental uncertainty can be reduced by gathering social information i.e. extracted from observations of, or interactions with, other individuals (Wagner and Danchin 2010). Social information use is a taxonomically widespread decision-making strategy and has been found to aff ect various aspects of animal behavior e.g. habitat selection, mate choice, nest-site preference, and foraging behavior (Dall et al. 2005). In a breeding-site selection context, social information constitutes the presence or p...

Habitat selection is a decision-making process that birds use to select a habitat in which they live. It is crucial for individuals to make the correct choices, because their living space directly affects their fitness. When making settlement decisions, birds are faced with uncertainty about habitat quality. In order to reduce it, they have to acquire information, which makes their world more predictable. Acquisition and use of information about habitat quality is the central part of the habitat selection process. Individuals can acquire information about habitat quality in various ways, e.g., by using own breeding experience (personal information), or by observing behavior and decisions made by other individuals (social information). In this review I briefly described the types of social information which songbirds use to assess the habitat quality. By using unified approach, I evaluated their value and availability for individuals, concluding that simultaneous use of several types of information provide the most effective way to habitat quality assessment. Furthermore, I argued why tits (Paridae) constitute a crucial link in the chain of interspecific social information transfer within songbirds' communication networks throughout the Holarctic and suggested that they may be considered as the keystone cue-providers. Moreover, I evaluated current literature on the artificial-attraction methods and highlighted urgent research needs in context of its practical application in the conservation and management of songbirds populations.