A Bird's Eye View

Bird feeders act as central congregation points for local birds, but when they start panic buying, which species is top of the pecking order? A study carried out by the University of Exeter and the BTO suggests that heavier birds are more dominant at bird feeders, allowing species such as House Sparrows to gain superior access to higher “value” food that is either high in energy or efficient to consume (e.g sunflower hearts require less energy to eat than a sunflower seed with the husk still on). Goldfinches tucking into sunflower hearts - a high "value" food This idea of dominance was calculated by recording which of two feeders a bird visited (either a “low value” sunflower seed with husk feeder or a “high value” sunflower heart feeder), the length of time a bird spent on the feeder, how many pecks a bird made whilst at the feeder and the outcome of any interactions between birds of different species (i.e. would a House Sparrow displace a Blue Tit from a f

Coming into spring, with the first few Swifts arriving in the UK in the last week, this seems like an opportune moment to discuss how birds navigate in order to migrate. Whilst the feat of a tiny Willow Warbler travelling 12,000 km (in the case of  Phylloscopus trochilus yakutensis ) is humbling and physiologically incredible in its own right, migration becomes even more fascinating when you consider how the birds navigate, without the luxury of GPS, Google Maps and all the other tools humans need to find their way around. It is thought that some birds use the Sun to navigate whilst there is also evidence that points to Homing Pigeons using olfactory cues to navigate, building up a local “map” based on odours at each location. However, we can’t explain navigation without considering the cognitive abilities of birds and their ability to build mental maps. Perhaps the most remarkable way this is done is using the Earth’s magnetic field. Juvenile birds of some species on their first m