An ornithologist was interested in determining how many tree sparrows (Spizella arborea) were using the

feeders at her study site. To estimate the size of the flock, she mist-netted sparrows on six days in

October, 2022. Eighteen sparrows were caught on 15 October, and each of these were banded, i.e., n₁ =

18. She returned to the study site on 16, 17, 18, 19, and 20 October for more mist-netting to recapture

banded birds; she did not band any additional birds.