First nesting of a Greater Black-backed Gull in Urdaibai

This spring a Greater Black-backed Gull (Larus marinus) was watched hatching two eggs while the colony of Yellow-legged Gull (Larus michahellis) of the Island of Izaro was monitored for the capture and ringing of its members as the previous years.

This individual, a male that was captured, ringed and measured, was, allegedly, paired off with a female Yellow-legged Gull.

Although in the last years a very few couples of Greater Black-backed Gull were observed while they were showing a territorial behavior, this is the first occasion that a nesting of this species is detected, but it is important take into account that nowadays their southern distribution is spreading.