Moult Codes
I have been asked frequently of late to explain the use of Moult Codes when ageing and sexing different species of passerines. Understanding moult is essential for the correct ageing of most species so that the guidance in the Ringer’s Manual has been presented here to help trainee ringers to study moult further.
Juvenile Moult – J P O M A T
J |
wholly Juvenile plumage. Applies to all juvenile passerines prior to their Post juvenile body moult. e.g. A young Robin could be aged as a 3J with J in moult column. |
P |
A Post-juvenile passerine in body moult. |
O |
Includes some juvenile e.g. Robins that have completed partial moult (Red breast), but has still old coverts, wing and tail. |
M |
Includes some species e.g. Long Tailed Tit and Tree Sparrow in active moult of wings and tail. |
A |
Use this code if the moult of the wing (primaries or secondaries) has been arrested. |
T |
If only Tail or Tertials are in partial post-juvenile moult |
Familiarity with these codes will help ringers to age juvenile birds with increased confidence. The bird’s well being too can be judged, with juvenile feathers retained after moult, suggesting that the bird was not fully fit during the time of moult.
Adult Moult – O B M S E N
O |
Old plumage, no body or main moult |
B |
An adult undergoing active Body moult but not part of a full moult of wings and tail. |
M |
Main Moult of wings and tail. A moult score of one wing is a useful addition.
0 an old feather
1 feather missing, new one in pin
2 new feather up to one third grown
3 new feather from one to two thirds grown
4 new feather more than two thirds, but still signs of sheath |
S |
Starting Body Moult – old wings and tail |
E |
Ending Body Moult – new wings and tail |
N |
New plumage following main moult |
Example
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Comments and notes |
Robin |
3J |
J |
72 |
18.2 |
10 hrs |
GPM |
(Juvenile plumage) |
Robin |
3J |
P |
71 |
20.3 |
10 hrs |
GPM |
(In body moult) 10% red |
Robin |
3 |
O |
72 |
19.4 |
10 hrs |
GPM |
(Complete partial moult) 100% red |
Robin |
4F |
O |
70 |
19.6 |
10 hrs |
GPM |
Brood Patch (old plumage) BP3 |
Robin |
5F |
M |
71 |
18.6 |
10 hrs |
GPM |
Still yellow inside mouth (In Full Moult) BP5. Moult Score 21 |
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