second calendar year: July

Last update of this page: 27-09-05 18:47

The classification between the three types, as set up in the May and June section, is hard to maintain now moult in all feather groups is going on. Extreme differences may occur in all types. In the general section we describe the extremes as seen in July.

Remiges moult:

The average primary moult score for mid-July is about 25. On average, p7-p10 are still juvenile outer primaries, p4 is the latest full-grown second generation primary, while p5 and p6 are growing. The extremes found in year 2001: 
A: Delayed moult with only p1 and p2 shed, no new primaries growing (photo 20). The primary moult score is only 2. 

B: Most advanced moult by mid-July includes only p10 and p9 still juvenile and p7 already longer than p6, which is full-grown (photo 22). Moult score is 36 here. 
Such tremendous extremes in primary moult pace can probably only be found in the LBBG-complex; none of the other large white-headed gulls in Western Europe share this phenomenon. 

Some odd primary moult strategies may appear as well, e.g. growing p4 while p5 is still not shed (image 9 and 10). Normally, when a new growing p4 is over half of its final length, the next primary (p5) has been dropped, and, not uncommon, p6 as well. Actually, p4 at 50% and p5 still present may be an indication for arresting the primary moult, but there seems to be no good reason for such a moult strategy in July.

By the end of July, the first secondaries are shed. In many cases, the outer group of approximately 4 are shed (S1-4), then a small block of secondaries remain (app. S5-S9) and the inner secondaries (S10~S17) are shed as well, although often a few remain in the inner-arm (app. S15-S16). The secondary moult strategy resembles the strategy of 2cy michahellis in this respect, with the bulk of LBBG being later (August) in the moult of secondaries.

Rectrices moult:

As could be seen in the May Section, some 2cy LBBG had replaced the entire tail by May. This, of course is the early extreme, only shown by the vanguard of 2cy LBBG. Normally, July is the month where 2cy LBBG shows an incomplete tail. But still, all rectrices may be juvenile as well (as can be seen in image 14).

Scapulars and Wing-Coverts:

As can be seen in almost all the pictures, moult is in progress in both the scapulars and wing-coverts. 

Some advanced individuals have replaced the entire greater covert bar (image 6 and 24), but normally the central greater coverts are missing or still growing. The outer greater coverts are replaced inwards, after outwards moult of the inner (3-5) greater coverts and the two meet at greater covert #8 approximately. By July, the complete median covert bar has normally been replaced and the moult of the lesser coverts is taking place more randomly. The under-wing coverts probably follow the same sequence as the upper-wing coverts. The pattern on second generation under-wing coverts is more contrasting black-white than the old juvenile variegated brownish under-wing coverts. See e.g. image 19.

On average, the tertial moult is in progress, with the upper two tertials missing or growing in most 2cy LBBG (see e.g. image 10 for an individual with average moult pattern by early July).

By July, it is very difficult to be certain of the exact age of some scapulars. As could be seen in the September section of 1cy birds, many individuals moult scapulars to second generation feathers by late summer. By May, 2cy LBBG may show fresh scapulars again and it's hard to exclude that some individuals by then already have third generation, adult-like scapulars. And now again, by July, almost all 2cy LBBG show at least several fresh, recently replaced scapulars of which some may be of fourth generation. It's expected that these 4^th generation feathers appear very adult-like and indeed some individuals show abraded plain grey-brown scapulars combined with fresh adult-like feathers. It has to be said that ageing such scapulars is very hard and as long as (at least some) juvenile scapulars appear, fresh scapulars may be only second generation feathers (replaced very late).

Intermedius types:

By July, the majority of the local Dutch 2cy can be found in the Netherlands and this seems to be the period that many passage intermedius migrate north. Going through a group of 2cy LBBG in July (see image 1, 2 & 3), some individuals appear long-winged, short-legged and generally are more elongated than the average local Dutch 2cy LBBGs. In the captions these birds are mentioned "probable intermedius" as we presume these to originate from Scandinavian populations. Regarding moult pace and moult sequence, there is much overlap with the local Dutch LBBGs.

Photo 3: group, including 2cy LBBGs, July 6 2001, IJmuiden, the Netherlands.

Photo 5: 2cy LBBG, July 7 2001, IJmuiden, the Netherlands. Probably intermedius. P4 is growing and two central tail feathers are replaced for 2^nd generation feathers.

Photo 7: 2cy LBBG, July 7 2001, IJmuiden, the Netherlands. Primary moult score is 24 (p5 growing), average for 2cy LBBG in the first week of July.

Photo 9: 2cy LBBG, July 7 2001, IJmuiden, the Netherlands. Probably intermedius. 

Photo 10: 2cy LBBG, July 7 2001, IJmuiden, the Netherlands. Most common moult strategy and moult stage of local 2cy LBBG in the Netherlands by early July. 

Photo 11: 2cy LBBG, July 6 2001, IJmuiden, the Netherlands. 

Photo 12: 2cy LBBG, July 6 2001, IJmuiden, the Netherlands. Much resembling the previous bird, but on average much darker. Scapulars are not plain brown but dark grey-brown. 

Photo 13: 2cy LBBG, July 6 2001, IJmuiden, the Netherlands. An average 2cy, with much of the local characteristics, resembling the 2cy in image 10 in some respects.

Photo 14:  2cy LBBG, July 6 2001, IJmuiden, the Netherlands. As in many 2cy LBBGs, the central median coverts are moulted inwards. 

Photo 15: 2cy LBBG, July 6 2001, IJmuiden, the Netherlands. Barred individual, showing anchor pattern on the scapulars.  

Photo 16: 2cy LBBG, July 6 2001, IJmuiden, the Netherlands. Probably intermedius by jizz and very dark fresh scapulars. P6 shed and p5 growing. Relatively dark (presumed intermedius), with much marking on the head. Some intermedius may appear all white on under parts and head.

Photo 17: 2cy LBBG, July 6 2001, IJmuiden, the Netherlands. Bulky, robust 2cy with barred and anchored patterns on the coverts and scapulars. 

Photo 18: 2cy LBBG, July 6 2001, IJmuiden, the Netherlands. Individual showing bars on the new median and lower lesser coverts and plain brown-grey scapulars, with an accentuated shaft streak. 

Photo 19: 2cy LBBG, July 6 2001, IJmuiden, the Netherlands. First summer  LBBG with very plain patterned new coverts and scapulars. Centres are black and towards the fringes, the feathers become more brown-grey. Inner greater coverts are missing. P7 has been shed, p6 is just growing: moult score 29, relatively high.

Photo 20: 2cy LBBG, July 14 2001, IJmuiden, the Netherlands. P1-2 are missing, resulting in an exceptionally low moult score compared to other 2cy LBBG by mid July.

Photo 21: 2cy LBBG, July 14 2001, IJmuiden, the Netherlands. P6 is growing and p7 is missing. Median coverts are renewed inwards. Note the bluish tibia.

Photo 22: 2cy LBBG, July 15 2001, IJmuiden, the Netherlands. P7 is new, p8 missing: moult score 36, which is pretty high for LBBG.

Photo 23: 2cy LBBG, July 15 2001, IJmuiden, the Netherlands. Primary moult not symmetric: right wing p6 juvenile, left wing p5 juvenile, p4 growing.

Photo 24: 2cy LBBG, July 15 2001, IJmuiden, the Netherlands. A complete 2nd generation plumage, ready for 2^nd winter. P8 is missing, p9 is still juvenile; moult score is 36. Tail renewed. 

Photo 25: 2cy LBBG, July 15 2001, IJmuiden, the Netherlands. The greater coverts are moulted inwards and the complete visible wing (except the upper lesser coverts) is 2^nd generation. The complete tail has been shed and new tail-feather tips are just visible, but still shorter than the under-tail coverts.