Plot with stable carbon on the X-axis and stable nitrogen on the Y-axis, showing the difference in isotope values between predator (black-legged kittiwake) and prey (fish and invertebrates). Black-legged kittiwakes are in the middle of the plot, below Arctic cod.

After accounting for dietary discrimination, #δ13C and #δ15N #isotope values in kittiwake livers were at a lower #trophiclevel than Arctic cod.

What does this mean? While kittiwakes do consume Arctic cod (as seen in stomachs), stomach analysis may underestimate soft tissue prey, such as #inverts.