Migrating geese make an awesome sight but this group in Bulgaria witnessed the ultimate event for birders.
1 March 2004 was an unforgettable day for Christian Dronneau and his friends Benoit Wassmer and Christian Frauli.
They had arrived at Lake Durankulak with their guide, Pavel Simeonov.
Little did they expect to witness the departure of the globally threatened and beautiful Red-breasted Geese Branta ruficollis for their Siberian breeding grounds, a once-in-a lifetime spectacle.
That the geese were unusually excited was immediately obvious, as flock after tightly packed flock leapt into the air,
leaving the larger White-fronted Geese Anser albifrons peacefully grazing the cornfields beneath.
That the Red-breasts were engaged in a ritualised prelude to migration itself was recognised by Pavel Simeonov,
who explained to his guests the significance of the locations between which the geese were moving.
One was their main drinking place, the other, one km away, was their favourite grazing area, both to the west of the lake.
The whole performance, involving at least 5,000 birds, was like an ecstatic dance, played to the accompaniment of peculiarly sharpened versions of the birds' normal yelping cries.
Spellbound themselves, the human audience watched as parties of Red-breasts began to detach themselves from the main flocks and, in chevron formation - the ancient hallmark of migrating geese - made for the north with unfailing precision and purpose.
In the space of less than an hour the spectacle had become a memory and the fields seemed deserted.
The beautiful Red-breasts had left their Bulgarian wintering grounds for the far north.