Roughly, assuming a constant population and its random mixing between the time of tagging and the time of observing hawks at the feeder, the proportion $10/N$ of tagged hawks in the population should be estimated by the proportion $6/28.8$ at the feeder. So we estimate $\hat N = 288/6 = 46$ hawks in the population.

Note: This 'Lincoln-Peterson' method fails if no tagged hawks are seen at the feeder. See Wikipedia and other references on mark-recapture or capture-recapture estimation` for somewhat more satisfactory methods.

Roughly, assuming a constant population and its random mixing between the time of tagging and the time of observing hawks at the feeder, the proportion $10/N$ of tagged hawks in the population should be estimated by the proportion $6/28.8$ at the feeder. So we estimate $\hat N = 288/6 = 48$ hawks in the population.

Note: This 'Lincoln-Peterson' method fails if no tagged hawks are seen at the feeder. See Wikipedia and other references on mark-recapture or capture-recapture estimation` for somewhat more satisfactory methods.