Birds able to learn from other species, researchers find
Certain birds are able to learn not only from individuals of their own species, but from birds of other species, according to new EU-funded research. Writing in the journal Current Biology, Janne-Tuomas Seppänen of Jyväskylä University and Jukka Forsman of Uppsala University describe how female flycatchers tend to choose nest boxes which closely resemble those already inhabited by great tits and blue tits. The researchers came up with the idea for their experiment while looking for nest boxes in a dimly lit forest one morning. They realised that it would be easier to spot the nest boxes if they were conspicuously marked in some way, and wondered if these markings would influence the birds' behaviour. Earlier research had shown that flycatchers often seem to pay attention to the choices of both other flycatchers and tits when picking a site to breed. 'Animals are not merely programmed to behave in a fixed manner, but use information and make decisions,' explained Mr Seppänen. 'Most importantly, individual animals live in communities, and they may learn from each other, even from other species.' Flycatchers and tits have a lot in common; they eat similar food and like the same kinds of nesting sites, meaning that they often compete for resources. However, while the tits stay in the same place year round, the migratory flycatchers do not arrive at the breeding site until spring, when the tits are already busy raising their families. Because they are resident year round, the tits probably have more local knowledge than the migratory flycatchers. With this in mind, the researchers wondered whether newly-arrived flycatchers would look to the tits for information on what makes a good nest. To test their theory, the researchers visited two breeding sites after the tits had started nesting but before the arrival of the flycatchers. They fixed stickers with one distinct, geometric symbol onto the nest boxes inhabited by tits, and placed a different symbol on an empty nest box nearby. This created the impression that all the tits had gone out of their way to choose nest boxes marked in the same way. When the flycatchers arrived at the site they were confronted with a choice: either they could pick a nest box marked like those of neighbouring tits, or they could pick a nest box with a different mark. The flycatchers that arrived at the site early on in the season showed little interest in copying the tits. However, as the season wore on, more and more flycatchers went for nests with the same mark as the tits' nests. Among the last third of the female flycatchers to arrive, 75% chose these nests. One reason for these results could be the age difference between the first and last birds to arrive. 'Earlier-arriving birds tend to be older, more successful individuals with previous breeding experience,' explain the researchers in their paper. 'Thus, they may possess more and better personal 'knowledge' about breeding in general and about the particular location.' Another reason could be time; flycatchers' breeding success is reduced if they lay their eggs too late in the season. So while early arrivals have time to take a range of information into account in their hunt for good nesting sites, late arrivals are under strong pressure to find a nest site quickly. 'Later birds, with higher proportions of younger and inexperienced birds, facing reduced breeding success and greater competition for nesting sites, can do the best of a bad job by blindly following the choices made by others with more knowledge,' the researchers write. 'Conventional theory of species coexistence predicts that overlaps in resource use between species results in costs and divergence of niches,' explained Mr Seppänen. 'However, our results suggest that if information possessed by another species - even by a strong competitor - is valuable enough, interspecific social information use and social learning in particular may lead to increased co-occurrence, proximity and niche overlap between species.' EU funding for the work came from a Marie Curie Intra-European Fellowship.