General description:

By May the numbers of 3cy and 4cy michahellis slightly increase at Etaples in NW France and by June, several 100's can be found in the region (Etaples, Dannes, Boulogne-sur-Mer, see the Le Portel Page).
The general appearance of 4cy michahellis in June is rather straightforward. All individuals still have P10 present, so show a white mirror on the outermost primary. This is an easy clue for separating it from 3cy birds. 4cy show adult-like primaries, but still the outer greater primary coverts are dark, unlike full adult birds. An example of the average 4cy michahellis can be found in the first image, an individual ringed near Marseille, S France, showing some worn grey wing-coverts. The brown primary coverts are obvious in this bird.

Moult of remiges and rectrices in June:

As soon as P2 and P3 are dropped, most birds start to shed the outer median coverts, followed by the upper tertials and innermost greater coverts. Subsequently, the inner median coverts are dropped. This is the moult stage shown by most sub-adult michahellis by the end of June. The average bird may also shed outer lower lesser coverts and the upper tertial, when moult progresses (P5 shed).

The rectrices have the tips worn away and may even look very abraded in 4cy michahellis. By June, the partial spring moult has finished, and a small minority of 3cy michahellis included some rectrices in this moult. These birds show a 'blocked' tail pattern. Sub-adult birds may include tail feathers in the partial spring moult as well, but both generations are plain white and may only be recognized at short range when the state of wear can be established. The complete moult in the rectrices and secondaries have not started yet by late-June 4cy michahellis.

See the Topography Section for explanation of feather tracts.

Timing and strategy of body & covert moult in June:

We didn't described enough sub-adult birds in detail to draw detailed conclusions, the sample size has been too small. A few preliminary conclusions on 4cy michahellis:

• Head-streaking, which was obvious during the winter months and concentrated on the ear-coverts, around the eye and up to the crown from September to March, has been replaced by snow-white fresh head-feathers. The head and under-parts are white by May and still white in June.
• 4cy birds show grey upper-parts, but there is a strong brown hue on the central greater coverts and worn inner lower lesser coverts.
• Some birds show moult in the head-feathers: "moth-eaten" appearance.

See Topography Section for explanation of feather tracts.

Tables:

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