What are the Benefits of migration

Eg:

• Need to leave Alaska due to harsh weather conditions (statement that birds are escaping NZ winter not acceptable).
• Longer day length increases chance of survival of the juveniles.
• Experience improves success rates / faster trips by older birds / laying down of more fat.
• Usually a more successful reproductive rate among migrants is due to rapid feeding of young because of a rich and plentiful supply of food. This occurs in migrants that reproduce usually once at high latitudes where they will only have a short period of continuous light. Or they may get a chance to reproduce more than once if the migrants are at lower temperate latitudes and the favourable conditions last longer.
• Lower chance of predation if the migrant is in an area for a shorter period of time. Also, the effect of predation will not affect a large group migrating at once - only young, old and weak individuals will usually be removed, increasing the fitness of the population.
• Ability to use abiotic factors to assist migration such as favourable wind directions.
• Ability to select the timing of departure to enable the migrant to arrive at its destination in favourable conditions or as these conditions are becoming favourable. The stopover in Korea would allow the godwit time for conditions to become favourable in Alaska as well as a chance for them to rebuild tissues for the long flight.
• Reduces inter-specific competition with non-migratory animals.
• Staging on the journey from NZ to Alaska enables the Godwit to have an improved body condition upon arrival at the breeding site in Alaska. This staging is not essential on the journey back to NZ as on arrival in NZ they are not breeding.