Interspecific and Local Variation in Tern Chick Diets Across Nesting Colonies in the Gulf of Maine

The Gulf of Maine, USA is home to four colonial co-nesting tern species: Least Tern (Sternula antillarum), Common (Sterna hirundo), Arctic paradisaea), and the federally endangered Roseate dougallii). Over three decades visual observations chick provisioning were compiled for a comparative dietary study in region, including first detailed descriptions diets. Three prey groups comprised majority diets among species between 1986–2017: hake (Urophycis spp. or Enchelyopus cimbrius) 28–37% frequency occurrence (FO), sand lance (Ammodytes americanus A. dubius) 8–22% FO, herring (Clupea Alosa spp.) 3–30% FO. Dietary contributions varied across islands. At two inshore colonies, contained higher amounts (30–42% FO), while offshore islands lesser (5–9% FO). Overall diversity (H?) was similar (H? = 1.57) Terns 1.74) notably lower 1.24) 1.37), whose primarily piscivorous. degree plasticity general feeding ecology provided by baseline information can inform holistic assessments risk ongoing future disturbances from fishing climate change.