Why Do Rock Sparrows Decorate Their Nests?
Scientfic American - 15/01/2015 Ir a fuente de la noticia
Nota de Prensa: When you read the word ‘communication’, you probably think of language in some form, likely spoken or written. This is because, as humans, we’re obsessed with communicating through language; it’s likely that an hour doesn’t go by in your day when you don’t communicate with someone by phone, email or text.
While animals are generally thought to not have language akin to that of humans, there are a plethora of other ways that they communicate with one another. Previously I’ve written about the elaborate courtship displays of bowerbirds and gift-carrying spiders. Decorations, like those on bowerbird’s bowers, are rather attractive to us, but their actual purpose is to signal the prowess of the individual creating them.
A recent study by Vicente García-Navas and colleagues found that rock sparrows also use decorations to communicate. Like orb web spiders, the behaviour of making this decoration probably evolved from a behaviour with a very different function. The main purpose of birds’ nests is to hold birds and their offspring, first as eggs and then as chicks. They are often built to keep eggs warm and protect the individuals from bad weather and predators. However, it seems that rock sparrows have taken this a step further. Males and females of this species collect the feathers of other birds (such as jays, raptors, magpies and pigeons) and bring them back to the nest. Here the feathers are displayed conspicuously ‘like hunting trophies’. But why do these birds do this?