third calendar year: January - April During April only the very first of 3cy birds return to the colony. The first arrive around mid-April, the majority around mid-May in the Netherlands. They join the adults arriving as early as possible to find the best breeding spots in last years colonies. The counted maximum number of 3cy’s estimates 100 (mid-May), on the total of 1.500 LBBG present at the Maasvlakte, the Netherlands. Higher numbers can be found on the wintering grounds (Portuguese coast and in S France) or at the stop-over places (e.g. Pas-de Calais). moult
stage
in typical 3cy LBBG: moult
in advanced
3cy LBBG: tail-feather
& p rimary
moult in advanced LBBG : 3cy
LBBG in spring may include tail-feathers in the partial spring moult
again, and may still be actively replacing rectrices in April (see e.g. image
8861). About 30% of the 3cy LBBG have moulted one or more tail feathers
by the end og April, giving them the blocked pattern of white (third or
fourth generation feathers) and partial black tail-feathers. The partial moult involves rectrices randomly,
creating an unpredictable black and white tail in spring. At the end of April only the very advanced birds have started the complete moult and have shed P1. The ordinary moult-sequence of the secondaries start when P6 is almost fully grown, by mid-summer. But here again, primaries and secondaries may be included in the partial moult on the wintering grounds. Image 283 nicely illustrates arrested primary moult in spring 3cy LBBG. On the wintering grounds, partial moult must have been very extensive in the upper-parts, as almost all wing-coverts are very adult-like. In this extensive moult, the inner primaries were moulted as well, just as most of the tail-feathers. In this respect, the western taxa intermedius and graellsii LBBG may resemble eastern fuscus., which very commonly replaced remiges and rectrices on the wintering grounds. |
photo 1: LBBG 3cy, January 03 2002, Boulogne-sur-Mer, France (50.42N,1.34E). A rather advanced individual in having most of the scapulars and coverts brown-grey. |
Photo
2: LBBG 3cy January 5 2001, Westkapelle, the Netherlands. Here a 3cy (by January) bird. The new second generation primaries lack white tips and are tar black. |
8861: LBBG 3cy March 15 2003, Boulogne-sur-Mer, France (50.42N,1.34E). The new generation primaries lack white tips and are tar black. |
Photo 3: LBBG 3cy, April 16 2001, Bairds strandje, Maasvlakte, the Netherlands. Primaries are black without tips and both bill and legs show already pale yellow coloring. |
Photo 0283: LBBG 3cy, April 19 2003, e-on - Maasvlakte, the Netherlands. Arrested primary moult at P7. |