Ingested particle coloration was classified for all debris except
birdshot (7/39, 17.9%), because we assume birds encounter this by accident
and it becomes retained as if it were grit (a mixture of mineral,
rock, and hardened food fragments retained to aid in fibrous food diges-
tion; Thomas et al., 1977). Light-colored anthropogenic debris was more
commonly ingested (27/32, 84.2%) than dark colored (5/32, 15.6%)