Ivo Jacobs, PHD-student at LUCS, recently got interviewed by WIRED regarding the paper Object caching in corvids: Incidence and significance. For up-to-date news regarding the corvid research at LUCS check out: corvidresearch.blogspot.se/

Here is a summary of the content of the paper:

Corvids are birds like crows, ravens and magpies, and they are well-known to steal shiny objects such as rings and coins to hide them elsewhere. Because so little research has been done on this subject, we investigated why they might do so. We gave a set of 16 different objects to three corvid species (ravens, jackdaws and New Caledonian crows), and looked at their behaviour over eight trials. We found that all species interacted with and cached objects. The ravens did this more than the other species, which was no surprise because they cache food extensively and their object-caching behaviour has been documented before, being a developmental stage to practise food caching or to learn how other individuals might steal their caches. Surprisingly, jackdaws also cached objects although they do not normally cache food. Both species preferred to cache round objects, possibly because it resembles food, fits easier in their beaks or is rarer in nature, which could explain why the stories usually involve precious objects that these birds would not encounter in the wild. The New Caledonian crows mostly cached stick-like objects, which corresponds to their natural tool-using behaviour, when they use sticks to pry out embedded invertebrates. Previously proposed hypotheses do not hold, because we tested the birds outside the breeding season (so it is not related to nest building), cacheable food was present (which they were expected to take if they were just very motivated to cache anything), they were tested individually (so any social function does not apply), and they do not all use tools. Therefore, object caching in corvids seems to be a manifestation of their high levels of curiosity and playfulness, which enables them to innovate and exploit the environment, making them such successful birds worldwide.