Professor Ben Sheldon
Appearances
Global News Podcast
Ukraine accepts 30-day ceasefire
So what we were interested in was trying to understand why it is that you get variation in the pattern of different song types in a population. So we know that song in birds like great tits is learned when birds are early in their lives, in their first year of life. And then the birds will sing more or less the same range of song types throughout their life. But if you go...
Global News Podcast
Ukraine accepts 30-day ceasefire
through a population, through woodland, you can hear lots of sort of different song types. The greater has quite a characteristic song, sometimes described as a squeaky hinge. We're saying teacher, teacher. Actually, there's lots of variation in the population. So sort of different song types sung by different individuals.
Global News Podcast
Ukraine accepts 30-day ceasefire
It's got a little repertoire. So it has synced between four and ten song types. It keeps those over its life. And of course, it's learned those. So where it was growing up and then it's moved to sort of settle down and breed itself. So in principle, it takes its songs from its local environment with it and brings them to a new place.
Global News Podcast
Ukraine accepts 30-day ceasefire
If you compare birds that are born at different times, that older birds sing slightly different types of songs than the younger birds. So if you have an area that is primarily composed of older birds, it will sound slightly differently than one bird born just a year or two or three later.
Global News Podcast
Ukraine accepts 30-day ceasefire
So if you have an area that is composed of a mix of ages, that's actually where you get the most variation locally. So you'll have the sort of most variable soundscape, if you like, is when you've got lots of different ages of birds in a place. And that's really nice because it shows us that these old birds are kind of sort of act as cultural stores of these songs in the past. Yeah.
Global News Podcast
Ukraine accepts 30-day ceasefire
Why do we think they evolved to sing? Two main reasons that the male birds are singing. Females sing as well, but that's been neglected. But males sing at this time of year for two reasons. One is to advertise their presence. If they haven't got a mate, they're appetising the fact that they're there and they're available to a female if she wants to come along and breed with them.
Global News Podcast
Ukraine accepts 30-day ceasefire
And then they're also singing to other males, effectively saying, this is my bit of the woodland, keep out.
Global News Podcast
Ukraine accepts 30-day ceasefire
You can tell, in a sense, all of these songs sound like a great song, even if they sound a bit different from one another. So it's not that they won't understand each other.
Global News Podcast
Ukraine accepts 30-day ceasefire
There is some evidence that when populations of birds get really small and fragmented, so when birds become rare, then you can have this problem that effectively birds may not learn to recognize all of the variants of song as being of their own species. So you can then have some degree to which the sort of recognition of species breaks down.
Global News Podcast
Ukraine accepts 30-day ceasefire
Obviously, if a population is large and there's lots of movement, then that means that the song types move around and the birds get exposed to lots and so on. So it's not a problem with the common bird like the great tit, but actually there is some research suggesting that this can become a problematic issue when populations become very small and fragmented.