Seasonal, sexual and developmental differences in hoopoe Upupa epops preen gland morphology and secretions: Evidence for a role of bacteria

1. Martín-Vivaldi, M.
2. Ruiz-Rodríguez, M.
3. Soler, J.J.
4. Peralta-Sánchez, J.M.
5. Méndez, M.
6. Valdivia, E.
7. Martín-Platero, A.M.
8. Martínez-Bueno, M.