Question

European blackbirds are facultative migrants; some fly south for the winter while others remain on their breeding grounds all year long. The chance that a bird will migrate in a given year is influenced by whether or not it migrated in the previous year. In one population, 70% of birds migrated in the previous year. Those that migrated in the previous year have a 60% chance of migrating in the current year. Those that did not migrate in the previous year have a 10% chance of migrating in the current year. Draw a probability tree and calculate the probability that a bird selected at random will migrate in the current year. (5 marks)

Answer 1