One of the more exciting projects we conduct on the Farallones is the Cassin's auklet known-age study, which was first initiated in 1983. The birds are known-age because they are banded as checks, and once those chicks recruit into an unoccupied nest box we can gather valuable information on mate selection and retention, changes in breeding performance with experience and age, and signals of individual quality; all of which help managers better understand how individual contributions lead to population level changes. The work involves checking the contents of over 400 nest boxes distributed across the island, and taking various measurements of adult birds like bill depth, wing chord, and weight, which are used to determine body condition and sex. 

Photo taken through Point Blue Conservation Science | USFWS