Urbanization is rapidly changing ecological niches. On the inhabited Galapagos Islands, Darwin's finches consume human-introduced foods preferentially; however, it remains unclear why. Here, we presented pastry with flavour profiles typical of human foods (oily, salty and sweet) to small ground finches (Geospiza fuliginosa) and medium ground finches (Geospiza fortis) to test if latent taste preferences might drive the selection of human foods. If human food flavours were consumed more than a neutral or bitter control only at sites with human foods, then we predicted tastes were acquired after urbanization; however, if no site differences were found then this would indicate latent taste preferences. Contrary to both predictions, we found little evidence that human food flavours were preferred compared with control flavours at any site. Instead, finches showed a weak aversion to oily foods, but only at remote (no human foods present) sites. This was further supported by behavioural responses, with beak-wiping occurring more often at remote sites after finches tasted flavours associated with human foods. Our results suggest, therefore, that while Darwin's finches regularly exposed to human foods might have acquired a tolerance to human food flavours, latent taste preferences are unlikely to have played a major role in their dietary response to increased urbanization.

Wildlife trade, when unsustainable, can be an important threat to biodiversity conservation. In this contribution, we explored the use of digital data to investigate the online market for songbirds in Indonesia, where keeping pet songbirds is a deeply rooted cultural practice. We examined the spatial characteristics of three dimensions of the songbird trade using data from online sources: birdwatchers’ sightings as a proxy for the supply of the songbird market, small advertisements from an online marketplace platform, representing the trade itself and its transactions, and videos by pet songbird owners to represent the demand side of the songbird market. We found that, geographically, these three stages of the songbird supply chain did not overlap, which potentially hints at the roles extended transport networks and commercial captive breeding play for the songbird trade. The trade was not confined to major cities but spread out through the country, indicating both a possible democratisation of the trade (i.e. a larger group of sellers, and consumers selling to consumers) and an opportunity to observe previously covert parts of the trade. We further found that the asking prices on online marketplaces were significantly higher than the prices stated in an independently carried out consumer survey, and discuss possible reasons. Data from digital sources can give rich insights into the spatial, temporal and taxonomic structure of wildlife trade, can help understand the motivations of buyers and sellers, and can help direct wildlife trade towards a more sustainable fashion. Our methodology toolbox that allows automatic and continuous monitoring of online marketplaces and includes data preparation and cleaning, and follows the highest standards of data privacy principles, is openly available.

Climate change has been shown to shift the seasonal timing (i.e. phenology) and distribution of species. The phenological effects of climate change on living organisms have often been tested using first occurrence dates, which may be uninformative and biased. More rarely investigated is how different phases of a phenological sequence (e.g. beginning, central tendency and end) or its duration have changed over time. This type of analysis requires continuous observation throughout the phenological event over multiple years, and such data sets are rare. In this study we examined the impact of temperature on long-term change of passage timing and duration of the spring migration period in birds, and which species' traits explain species-specific variation. Data used covered 195 species from 21 European and Canadian bird observatories from which systematic daily sampling protocols were available. Migration dates were negatively associated with early spring temperature and timings had in general advanced in 57 years. Short-distance migrants advanced the beginning of their migration more than long-distance migrants when corrected for phylogenic relatedness, but such a difference was not found in other phases of migration. The advancement of migration has generally been greater for the beginning and median phases of migration relative to the end, leading to extended spring migration seasons. Duration of the migration season increased with increasing temperature. Phenological changes have also been less noticeable in Canada even when corrected for rate of change in temperature. To visualize long-term changes in phenology, we constructed the first multi-species spring migration phenology indicator to describe general changes in median migration dates in the northern hemisphere. The indicator showed an average advancement of one week during five decades across the continents (period 1959-2015). The indicator is easy to update with new data and we therefore encourage future research to investigate whether the trend towards longer periods of occurrence or emergence in spring is also evident in other migratory populations. Such phenological changes may influence detectability in monitoring schemes, and may have broader implications on population and community dynamics.