Sighting in Bayonne, March 16, 2019

At about 1:55 a.m., a witness standing in their garden noticed seven points passing silently across the night sky. Each looked like a rather blurry white disc. They formed a geometric pattern and crossed the sky from southwest to northeast in four to five seconds, then vanished behind the roof of the house. There was only one witness and no photograph. The questionnaire contained an error in the date, which was corrected during the investigation.

GEIPAN concluded that the witness had very probably seen a group of white-plumaged birds, most likely gulls, flying silently toward a nesting site. The housing estate is surrounded by wetlands suited to such birds, and the season fits the nesting of some species as well as the spring migration of others. The flight was straight, steady and grouped, which matches the behaviour of these birds. After a slight adjustment of the witness's measurements, calculations gave a speed and size consistent with those of such birds flying at 20 to 30 metres in altitude. At that time of year their heads and wings are black, so from the ground only the white underside was visible against the dark sky. This explains the pale discs, the underestimated size, and the absence of visible wings or wingbeats. Distance, possible haze (not confirmed) or reduced eyesight may have prevented the witness from making out the real shape.

The account is of good quality but of medium consistency, since it comes from a single witness. The case is only slightly strange, with a straight trajectory and moderate speed. It is classified B: probable observation of light-plumaged birds flying in formation.