Kelp Gull (Larus dominicanus)

(last update: March 12, 2015)

2nd cycle Kelp Gull (Larus dominicanus)

For Kelp Gull, the breeding season runs from January to December, with juveniles also hatching in December. Therefore it seems wise to use the Humphrey & Parkes annual cycle terminology (An Approach to the Study of Molts and Plumages, The Auk 1959, Vol 76-1). The cycles can be illustrated as:

Every year, there is partial moult, the pre-alternate moult, which turn the birds into hormonal breeding conditions, with rich coloured bare parts and a moult of head and underparts. This "breeding plumage" only lasts over a short period, as within months the complete moult starts with shedding of P1 (the pre-basic moult). In this pre-basic moult, all primaries, wing-coverts, rectrices and secondaries are replaced in a more or less fixed sequence.

As Kelp Gull is a southern hemisphere breeding species, the moult cycle is about half a year ahead (or behind, but this is irrelevant for the terminology) of northern hemisphere taxa. The difference in moult timing is an important ID feature for recognision of out-of-range birds. In 1st cycle, the main difficulties probably arise with Lesser Black-backed Gulls.

2nd pre-basic moult (December)

In a colony in Simonstown - Kaapstad, on the Cape Peninsular, breeding was advanced and the young had reached the stage of almost flying by mid-December. The primaries on most juveniles were not quite fully grown.
This sets a useful time marker for looking at the age and moult timing of older immature birds. If we take December as time zero, then birds hatched in November or December can be taken as ~12 months old in South Africa.

Immature birds appeared to be in active moult by mid-December, but could still be aged based on the presence of retained first generation (worn and pointed juvenile) primaries. If any bird with extreme advanced moult has to be aged in this period, 2nd gen primaries would still be glossy and blackish.

Plumage in first stage of 2nd cycle (birds in 2nd pre-basic moult)
Second generation feathers on mantle, coverts and tertials are variable: in some birds brown and coarsely patterned, in other birds more advanced looking with plainer and more grey feathers.

Primary moult in first stage of 2nd cycle (birds in 2nd pre-basic moult)
Sample size is too small for full statistical analysis on the birds observed in mid-December at Kaapstad. Out of 25 photographed birds the modal number of full grown 2nd gen primaries was 4. Number however ranged from zero to 8 fully grown primaries (NB the bird with zero had P1 and 2 partially grown, so, also this bird started the complete moult).
The pattern on new inner primaries is mostly brown with limited white at the tips, but birds had extensive white tips to quite grey new primaries. Such more advanced looking innermost primaries, suggesting 3rd gen or older, can also be found in some 2nd cycle Lesser Black-backed Gulls.

Secondaries in first stage of 2nd cycle (birds in 2nd pre-basic moult)
Unmoulted on most birds. However, occasionally some 'random' replacement of mid-secondaries. Also some apparent 12 month old birds had broad white tips to new secondaries.

rectrices in first stage of 2nd cycle (birds in 2nd pre-basic moult)

Birds with average post-juveile moult do not include rectrices, therefore they are retained old juvenile in the first stage of the 2nd pre-basic moult. If the ordinary moult sequence is followed, they will drop rectrices when moult in the primaries is halfway.
However, several individuals show some to all tail-feathers replaced for 2nd gen, included in the last (post-juvenile) moult. These feathers still show white tips, and fine proximal vermiculation, but may be slightly worn already by mid-December.

DECEMBER - 2ND PRE-BASIC MOULT

JANUARY - 2ND PRE-BASIC MOULT

FEBRUARY - 2ND PRE-BASIC MOULT

APRIL

JUNE - 2ND BASIC PLUMAGE

AUGUST - 2ND BASIC PLUMAGE

OCTOBER

DECEMBER