Photo 6: LBBG intermedius sub-adult (5cy?), June 17 2001, Missouriweg Maasvlakte, the Netherlands.

Very dark intermedius LBBGs may frequent the colony and establish mixed couples with paler Dutch intergrades. Notice the brand new primaries; hard to believe these are already half a year of age and note that some feathers lacking around the eye. Head feather moult is common by mid June in the colony at the Maasvlakte.
Intermedius LBBG may show very small primary tips, as can be seen in many fresh primaries in the winter section, but here the tips are rather large.
The bill shows a faint dark line just above the gonydeal spot, indicative for immatures.
Since intermedius is so dark, immature features, like dark feathers in otherwise grey wings, are hard to detect. Here, notice the upper tertials, which are not adult-like yet.
Typically, intermedius has an elongated look, with rather long pointed wings.
As seen in some immature LBBGs in June, the orbital ring again is not typically coral red, rather orangey.