Carbon d13C Isotopic Marker Values Correlate with Carotenoid-Based Bill Colouration in Adult Yellow-Legged Gulls Larus michahellis

1. Zorrozua, N.
2. Alonso-Álvarez, C.
3. DIaz, B.
4. Sanpera, C.
5. Jover, L.
6. Arizaga, J.