Winged seeds, or samaras, are believed to promote the long‐distance dispersal and invasive potential of wind‐dispersed trees, but the full dispersive potential of these seeds has not been well characterised. Previous research on the ecology of winged seeds has largely focussed on the initial abscission and primary dispersal of the samara, despite it being known that the primary wind dispersal of samaras is often over short distances, with only rare escapes to longer distance dispersal. Secondary dispersal, or the movement of the seeds from the initial dispersal area to the site of germination, has been largely ignored despite offering a likely important mechanism for the dispersal of samaras to microhabitats suitable for establishment. Herein, we synthesise what is known on the predation and secondary dispersal of winged seeds by multiple dispersive vectors, highlighting gaps in knowledge and offering suggestions for future research. Both hydrochory and zoochory offer the chance for samaroid seeds to disperse over longer distances than anemochory alone, but the effects of the wing structure on these dispersal mechanisms have not been well characterised. Furthermore, although some studies have investigated secondary dispersal in samaroid species, such studies are scarce and only rarely track seeds from source to seedling. Future research must be directed to studying the secondary dispersal of samaras by various vectors, in order to elucidate fully the invasive and colonisation potential of samaroid trees.

Birds build nests primarily as a receptacle to lay their eggs in, but they can also provide secondary benefits including structural support, camouflage and adjustment of the microclimate surrounding the eggs and offspring. The factors underlying intraspecific variation in nest characteristics are poorly understood. In this study, we aim to identify the environmental factors that predict nest height variation and the duration of nest building in blue tits Cyanistes caeruleus, evaluating latitude, elevation, temperature and the timing of egg-laying as predictors of nest height, while also taking into account female and male parental identity. Using 713 nest height observations collected over a period of five years along a 220 km transect in Scotland, we found that if the annual mean timing of egg-laying was earlier, nests were taller. However, there was no correlation between nest height and elevation, latitude, the minimum temperature in the 14 days pre-egg-laying or the phenology of birds within a year. Female parental identity accounted for a large amount of variation in nest height, suggesting that individual behaviour has an influence on nest structure. We also found that nest building duration was shorter when egg laying occurred earlier in the year, and that across all observations taller nests took longer to build. Overall, our results show that blue tits are able to alter their nest characteristics based on environmental gradients like latitude (in the case of building duration) and the annual mean phenological variation of egg laying, and that birds build relatively taller nests faster.

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