 Ethology is the study of animal behaviour (actions and habits) in natural conditions.  Animals are adapted to their natural environment and may act differently when removed so it always best to observe them here.

 This is the gradual, non random process in which biological traits become more common in a population or less common in a population due to how they influence the survival of that organism.

 All organisms want to reproduce and pass their genes on to the next generation.  If a biological trait gives an organism a better chance to survive, then that organism will likely survive long enough to reproduce and pass on the trait to the next generation.  If the biological trait does NOT give the organism a better chance to survive, then it is likely the organism will die before reproducing and passing the trait to the next generation.

 The trait may be an innate behaviour (one that is preprogrammed and in the genes of the animal)

 Stop here.

 Summer: Live and breed in Germany  Winter: migrate to Mediterranean (Spain)

MIGRATION  90% to Mediterranean  10% to UK

 Question #1: Is this direction of travel genetic? (Are the birds preprogrammed to migrate in a certain direction or are they just following their parents? Innate Behaviour Learned?)

 Eggs from both UK birds and the Spain birds were collected  The young birds were reared (away from their parents)  They were released during migration time and the direction of migration was recorded

 SPAIN BIRDS: No matter where they were raised, they flew south-west  UK BIRDS: No matter where they were raised, they flew west.  Therefore, it appears that the direction of migration is genetic!

 Question #2: Why would Blackcaps recently start migrating to UK instead of the tradition south-west direction of the Mediterranean? Is there an advantage to this?

 Due to climate change (and global warming), UK winters are not as cold or harsh as before.  Until recently, if a blackcap had a gene which led them to migrating in the UK, those blackcaps would likely not survive the harsh UK winter, and thus not pass on the gene to the next generation

 But since now UK winters are more tolerable, if a blackcap migrates to the UK, they will be able to survive the winter and reproduce in the following spring, and pass this trait on to the next generation.  Furthermore, since few blackcaps migrate to the UK, there will be less competition for food for these birds and thus may be overall healthier.  So the gene for migrating west continues to exist in the population.