Some outstanding questions:
1) Is Azorean Gull a genuine taxon? Is there are diagnostic suite of features which can seperate Azorean Gull from
a) other Atlantic Gulls
b) Yellow-legged Gull
c) Lesser Black-backed Gull
2) How reliable is the 'shin pad' feature as a tool in the identification of Azorean Gull?
3) If a diagnostic suite of features can be found, can Azorean Gull be identified in all age classes?
1) Descriptions and specimen photo collection of Madeiran, Canary Island and Continental European Atlantic Gull populations in all age classes.
2) The de-limitation of the contact zone between Atlantic Gulls breeding on the Iberian Peninsula and Yellow-legged Gulls breeding on the Atlantic coast? Where is the boundary. What is the nature of this boundary.
3)Extensive photo specimen collection displaying a very large sample of the variation shown within Yellow-legged Gull across it's entire range.
4)Genetic data from all populations
5)Vocalisation and behavioural/ecological data from all populations