Why are Birds getting Uglier?
A long term study of flycatchers has revealed that they are getting uglier! The ornamentation that has helped to make the male birds more attractive to the opposite sex has been disappearing and it is a trend which may start to affect other species. Birds might be about to get a lot less colourful.
The white patch on the male collared flycatcher’s forehead is supposed to indicate that he is a good mate. flycatchers have always grown a sparkling white patch on their forehead every breeding season. The more impressive the patch, the more successful they would be in finding a mate. Until now!
A major study conducted over the course of 30 years on the Baltic island of Gotland, has discovered that evolution has been reversed and the white patches are disappearing. The white patches are now having a negative impact on the birds’ chances in the mating game and so nature has seen to it that they have begun to disappear. Other studies have suggested that this is a trend which is occurring all over Europe and that other species may be experiencing the same phenomenon. But Why is this happening?
Climate Change and Ornamentation
Scientists are saying that it is global warming which is to blame. Global temperatures have risen during the course of the study. After a cold spring ornamented males did well in the mating game but after warm springs they did not. At some point in the mid 1990’s the balance of power changed and birds with smaller white patches became the preferred mates.
There is as yet no definitive evidence to demonstrate why warmer temperatures would make ornamented males less attractive propositions. However, the researchers believe that the trend is related to the birds’ chances of survival. Those who put the most effort into courting versus safety and survival are more vulnerable. The more extravagant the white feathers, the more they may attract predators. Female birds have started to make their choices based on which potential mate is most likely to survive.
The evolutionary change is happening so quickly that it is astonishing. In the early days of the study male birds with large white patches were found to be fitter than the less attractive birds but by the mid-1990s this situation had changed and it was the less ornamented males which were found to be in better condition. There had been a complete reversal in natural selection in just a few years.
Less Colourful World
If ornamentation is changing in flycatchers, then it is likely that other species will be similarly affected by climate change. But it is also possible that ornamentation could become more extravagant in other species. There could be winners and losers in the beauty stakes and only time will tell. It would certainly be a great shame if many of the colourful displays we see in nature were to disappear.