Data from: Stock composition of juvenile salmon taken by an abundant, pursuit-diving seabird in the coastal waters of British

We determined the stock composition of the juvenile salmon delivered to
offspring by a pursuit-diving seabird, the Rhinoceros Auklet (Cerorhinca
monocerata) on five breeding colonies in British Columbia, in 2012-2014.
We obtained 778 meals (bill-loads) in 11 colony-years, of which 215 (28%)
included salmon, and estimated stock composition for 126 pink, 101
sockeye, and 113 chum. The number, species, and stock composition of
salmon taken by the birds varied markedly among colonies and years. On the
two southernmost colonies there was a dramatic increase in the amount of
Fraser River sockeye in diets in 2012, the offspring of the exceptionally
large run up the river in 2010. The biennial cycle in pink salmon was also
evident: individuals from Puget Sound stocks featured prominently in diets
on colonies in 2012 and 2014, but were virtually absent in 2013 and
replaced by pinks from more northerly stocks. Salmon generally comprise a
minor proportion of Rhinoceros Auklet diets, but our results show that
these seabirds will respond to pulses of increased abundance of juvenile
salmon.