third calendar year: August

Last update of this page: 27-10-03 02:20 

• The bill becomes paler. Variation in bill colour is low. Bills with a black base (present in 9%, n= 100) are rare while some advanced birds (17%) show an adult-like bill. On average, birds show an adult bill with a dark smudge on the upper mandible (74%).
• The iris turns pale yellow, but a white or darker peppered iris occur.
• The head varies from all-white without any speckling (old, worn, 15%), finely streaked from crown to neck (65%) to new heavily streaked (20%). Birds actively moulting the head-feathers look spiky.
• The under-parts are actively moulted into white feathers. Nearly 100% of the birds shows all-white under-parts, a few have streaking in the hind-neck.
• By the end of August, all 3cy LBBGs show adult grey upper-parts.
• Many to nearly all 3cy LBBGs have finished moult of mantle and scapulars (by September all birds). The upper-parts resemble adults now (being 4^th or 5^th generation).
• Tertials on 3cy LBBGs in August can exist of old 2^nd generation (at least) feathers or newly moulted 3^rd generation feathers. The difference is obvious: the new tertials resemble adults, contrary to the blackish centred old tertials. About 50% of 3cy LBBGs have all tertials new, with new upper tertials and old lower tertials being second best.
• The wing-coverts are in active moult, so a gap in the covert bars is very common. The moult starts with the medians. When median covert moult is halfway, birds start moulting the greater and lesser coverts as well, normally starting with inner and outer greaters. Last moulted feathers are the outer lessers.
• Common moult-state in 3cy LBBGs by late August is:
  new inner and central medians (3^rd generation), 4 new inner greaters (3^rd generation), missing the central greaters and growing the outer-half inwards and 50% of the lessers old. The 3^rd generation coverts normally are adult-grey without barring.
• Primaries are moulted outwards, the primary-score by the end of August averages 34 (n = 26), all birds showing fully grown p4 at least (see table). Third generation primaries are very adult-like but p10 often shows an obvious smaller mirror. (Later in the year, bleaching gives a browner tinge on the primaries than on adults.)
• Secondaries are dropped inwards, from the moment p5 or p6 is halfway grown, creating a gap from p1 inwards. Only a very few 3cy show secondary-moult in August. No or nearly none 3cy show fully 3^rd generation secondaries by the end of August.
• The under-wing becomes paler, under-wing coverts are replaced by adult-like feathers. The under-wing coverts are probably moulted in the same sequence as the upper-wing coverts.

• The tail is old, 2^nd generation on many birds (60%), in active moult (20%) and fully grown 3^rd generation, white or with very restricted black markings (20%). Old worn tail-feathers occur as some 3cy and 4cy LBBGs may moult the tail on the wintering grounds, subsequently returning with a new tail in spring.

• Leg colour varies from pink to (pale) yellow.

• Birds with advanced mantle and scapulars already look exactly like 4cy birds as they return by May in the Netherlands.

Tables

 

	remaining old primaries							full-grown new primaries							# of new tertials
	0	1	2	3	4	5	6	p2	p3	p4	p5	p6	p7		0	1	2	3	4	5	6
15/8			2	10	10	3	2	2	4	9	10	3									1
21/8			2	7	6	3			4	6	6	2			1		2	5	1	2	4
23/8	1	2	12	8	5				1	4	13	9	1				3	5	5	3	12
28/8	2	4	11	6	3					5	7	8	6			1	1	3	10		11
31/8	2	7	14	9	4					6	14	11	5				3	5	12	5	11
	0: no old primaries left,  1: only p10 is still old, 6: p5 still 2nd generation.							p2: only p1-p2 new, others missing or old, p7: p1-p7 replaced 3rd generation.
	lesser coverts							median coverts							greater coverts
	0	1	2	3	4	5		0	1	2	3	4	5		0	1	2	3	4	5
15/8	1												1			1
21/8	4	3	4	4	1	2					2	1	15		1	4	9	1	1	2
23/8	7	4	3	4	4	6						4	24			7	6	2	8	5
28/8	2	1	2	5	9	7						4	22			4	3	2	9	8
31/8		4	10	5	8	9						5	31			5	5	4	9	13
Coverts score with 0 = all old, 1 = 25% new, 2 = 50% new, 3 = 75% new, 4 = 99% new, 5 = 100% new.

 

Primary moult score of 3cy LBBG, at Naaktstrand, Maasvlakte, the Netherlands (51.59N, 04.02E) on August 14 2003.
.	P3 fg	P4 fg	P5 fg	P6 fg	P8 fg	n:
P6-P10	2	-	-	-	-	2
P7-P10	-	7	-	-	-	7
P8-P10	-	1	10	1	-	12
P9-P10	-	-	-	14	1*	15
n:	1	8	10	15	1	36
* arrested moult at P8. P1 fg 4th gen, P2 growing, P3 missing, P4-P8 3rd gen, P9-P10 2nd gen. n = 35; m old P = 1.7; SD old P = 0.95. P8-P10 = P8-P10 are still old and present. Further notes: see previous table.

 

Primary moult score in 3cy LBBG, at Westkapelle, the Netherlands (51.33N, 03.25E) on August 15 2003.
.	P3 fg	P4 fg	P5 fg	P6 fg	P7 fg	n:
P6-P10	1	-	-	-	-	1
P7-P10	-	1	1	1	-	3
P8-P10	-	-	5	-	-	5
P9-P10	-	-	-	5	-	5
P10 old	-	-	-	-	1	1
n:	1	1	6	6	1	15
For notes: see previous table. Survey group of 82 LBBG, including 15 3cy.

LBBG Dutch intergrade L-9833? 3cy, August 01 2003, Zeebrugge, Belgium.

Photo 1: LBBG 3cy August 23 2000, Le Portel, France.

Photo 2: LBBG 3cy, August 18 2001, Missouriweg Maasvlakte, the Netherlands.

Photo 3: LBBG 3cy, August 18 2001, Missouriweg Maasvlakte, the Netherlands.

Photo 4: LBBG 3cy, August 16 2001, Vuurtorenvlakte Maasvlakte, the Netherlands.

Photo 5: LBBG 3cy, August 22 2002, Papegaaienbek, Maasvlakte, the Netherlands.

ARRESTED MOULT IN 3CY LBBG

LBBG 3cy August 29 2003, IJmuiden, the Netherlands. Probably intermedius, arrested moult at P8.