• Individuals behaving optimally will have more offspring.
• How do we measure this?
  • Number of offspring
  • Number of offpsring surviving to next generation
  • Lifetime Reproductive Success (LRS)
• These are all proxies and can be used to test a hypothesis, but not exacy

Example: Wytham Woods, Oxford Great Tit study

• Long term field study of great tits established in 1947
• Longest continuous study of individually-marked birds

Optimal clutch size: Important graph in the textbook (study this for exam!)

• Why is the optimum clutch size 10 according to a curve of maximum survival, but it's most common for there to be 8 eggs per clutch?
• Alternative hypothesis:
  • Does raising more young reduce parent's LRS?
  • Are there additional costs to rearing current young?
• Are there other trade-offs we need to measure to determine what causes the behaviour?
• Another later study showed that raising more young did reduce the parent's LRS.