Climate change can affect many animal and plant species in ways we cannot even imagine. From fragmentations in their habitat to changes in phenology and their cycles, climate change is causing many changes (some of them irreversible) in many species around the world.
In this case we are going to talk about the male of the collared flycatcher. A bird whose white spot on its head is of vital importance for its reproduction and mating. To what extent is climate change affecting this precious bird?
The Collared Flycatcher strategy
The male of the Collared Flycatcher has a white spot on the head and is of vital importance to your search for a female. The larger the spot on the head, the more attractive it is to females and the more likely they are to pass it on in their genes. This has been the case forever. However, over the past several decades, something has changed.
Climate change is negatively affecting this bird. It does so in such a way that the males with the smallest spot are surviving more than those with large spots and they are having more offspring.
The Collared FlycatcherFicedula albicollis) is a passerine bird, known as birds. It barely exceeds 18 grams in weight, nests in northern and central Europe, from which it flees as soon as the summer ends, taking refuge in Africa. It presents a great sexual dimorphism. The females are grayish in color, while the males combine black and white as if they were killer whales or pandas. In addition, they present a white spot on the front of the head, above the beak. The largest size of this spot is related to the possession of a greater territory and greater possibilities of attracting females and procreating.
Experts on these birds have been studying them for 36 years. The first times they were caught and ringed, they were verifying the reproductive success they enjoyed by having the largest head spot. However, in the mid-90s, things started to change and have accelerated over the past decade.
The dwarfing of the stain
In the second half of the studies carried out by the experts, it has been found that the males with the smallest frontal spot survive longer and have more offspring. It is estimated in the study that the reduction of the stain becomes 11% less. What caught their attention is that they did not know whether to relate the shrinking of the spot to their ability to adapt from the birds themselves for those with the smallest spot. But it didn't make sense since in the first part of the study, it was the ones with the largest stain who survived.
However, now in the present day, smaller-spotted neck flycatchers now have more territory and attract more females.
What has changed?
Experts have managed numerous variables to explain the reduction of the spot on the head. But they have stayed with those related to climate change. Because global temperatures have risen from the 80s to today, in the warmer springs (during the courtship and mating months) birds do better with smaller spots. That is why climate change would be exerting selective pressure in favor of the less gifted.
“We are not sure what creates the fitness difference, before or now. Perhaps climate change has made it difficult to breed these birds, especially since they must migrate to Africa. This may mean that the males with the largest spots have to work harder now: in addition to feeding their chicks, these males are involved in more confrontations with other males. It is the reverse of reproductive success. Large spots attract females, but also challenging males. " The experts of these birds comment.
As a conclusion it is drawn that the advance of the first and the movement to the north are the two effects of climate change that affect birds the most.