1. (Capture) mark – release – recapture

8. Step 3. Release the animals. (Capture) mark – release – recapture

9. Step 4. Recapture a second sample and count the number of marked individuals. Note: ensure the animals had time to mix with the rest of the population before capturing again. (Capture) mark – release – recapture

10. Step 6. Estimate population size using the formula. (Capture) mark – release – recapture

14. 1. Blue tits are common British birds. Some aspects of the behaviour of blue tits at different times of the year are summarised below. (a) In a study of winter feeding flocks, 36 blue tits visiting a bird table were trapped, and before release each bird was marked by placing a small metal ring round one of its legs. The following day 43 blue tits were trapped. Of these, 21 were ringed. Estimate the size of the blue tit population visiting the bird table. Show your working. March – April Adult birds establish breeding territories. April – July Breeding season. Eggs laid and young hatch. Adult birds collect food for their young from within their territories. July – March Birds form flocks which forage for food over a wide area.

15. (a) Working or explanation of figures; Correct answer = 74/73.7; 2