Asio otus - autumn

Long-eared Owl / Hornuggla

AGE - BEST CRITERIA:

In 1cy, all SS are uniformly juvenile, and show juvenile type barring. Older age classes show (most or all) SS with adult type barring, and in c. 35% of the birds at Ottenby, two different generations of SS are present. Two to four age categories are discernable, depending on the extent of the post-breeding moult of the individual.
 
1cy: 
  • Uniformly juvenile SS, lacking moult contrasts.
  • The barring of the SS is of juvenile type: 5-6 brownish and rather narrow bars visible above GC (use SS in the outer part of the arm). 
  • Juvenile SS and PP have a slightly paler and warmer brown ground colour.
  • The bars in the distal part of R1 is rather neat (although varying in width).

2cy+:
  • Uniformly post-breding SS, lacking feathers from last year's (more worn) generation. Very slight contrasts (or differences in length) is sometimes seen, but this is caused by the three different moult waves in the arm.
  • The barring of the SS is of adult type: 4 (or sometimes 5) dark blackish-brown and rather broad bars visible above GC (use SS in the outer part of the arm). 
  • Adult SS and PP have a slightly darker and colder greyish-brown ground colour.
  • The bars in the distal part of R1 is often rather diffuse and generally show a more vermiculated pattern.
 
2cy:
  • As 2cy+, but one or several juvenile SS still present in the arm, showing juvenile type barring, colour and wear.

3cy+:
  • As 2cy+, but one or several SS from last year's post-breeding generation in the arm, showing adult type barring, colour and wear.
1cy October. Uniformly juvenile wing without any moult contrasts. Dark tips to SS and inner PP rather diffusely set off, and the LC show weak and diffuse markings. [9119058]
1cy October, showing variation with slightly more well marked LC. [9119061]
2cy October (male). The complete moult was arrested, leaving worn and bleached unmoulted juvenile PP1-2 as well as S4 and S9. The new adult type feathers are fresh, broad, slightly longer and show a darker and more distinctly set off blackish tip. Note also the well marked LC. [9119076]
2cy October (female), showing variation with PP1-2 unmoulted juvenile while rest of wing is of adult type. [9119054]
3cy+ October (male). Older birds show adult-type feathers only. However, contrasts are often seen on multiple places in the wing, created by either retained (worn) feathers from last year or by the slight age difference in age of the feathers caused by the different moult waves. Importantly, note that none of the retained feathers are of juvenile type. [9119064]
3cy+ October (female), showing variation. [9119055]
1cy October. Uniformly juvenile wing without any moult contrasts. The hand is regularly clearly paler than the arm. [9119057]
1cy October, showing variation. [9119061]
1cy October (male)The complete moult was arrested, leaving worn and bleached unmoulted juvenile PP1-2 as well as S4 and S9 and some GC. The new adult type feathers are fresh, broad, slightly longer and darker. [9119076]
2cy October (female), showing variation with PP1-2 unmoulted juvenile while rest of wing is of adult type. [9119054]
3cy+ October (male). Older birds show adult-type feathers only. However, contrasts are often seen on multiple places in the wing, created by either retained (worn) feathers from last year or by the slight age difference in age of the feathers caused by the different moult waves. Importantly, note that none of the retained feathers are of juvenile type. [9119059]
3cy+ October (female). SS are uniformly post-breeding, showing no moult contrast (if a moult contrast is present, the age may be able to specify to 2cy or 3cy+). The SS show four adult type bars (a fifth bar is just visible behind the tips of the GC), rather broad and dark blackish-brown. The ground colour of the SS is rather cold greyish-brown. [9119062]
1cy October. Uniformly juvenile SS, lacking moult contrasts. The SS shows five bars (and a sixth bar is barely visible behind the GC tips). The bars are medium brownish and rather narrow, and the ground colour of the SS is rather warm yellowish brown. [9119063]
1cy October, showing variation. [9119061]
2cy October (male). Birds with less extensive moult of remiges show moult contrasts in the arm. This bird shows a largely unmoulted arm, and most SS are worn and slightly bleached. These unmoulted SS are of typical juvenile type, showing five or six narrow bars, in contrast to the single adult type S (in the mid-arm) showing adult pattern with four broad bars. [9119076]
2cy October (female). Birds with less extensive moult of remiges show moult contrasts in the arm. This bird shows a largely unmoulted arm, and most SS are worn and slightly bleached. These unmoulted SS are of typical juvenile type, showing five or six narrow bars, in contrast to the single adult type S (in the mid-arm) showing adult pattern with four broad bars. [9119054]
3cy+ October (male), showing variation of the adult pattern in the warmer coloured female wing. [9119064]
3cy+ October (female). SS are uniformly post-breeding, showing no moult contrast (if a moult contrast is present, the age may be able to specify to 2cy or 3cy+). The SS show four adult type bars (a fifth bar is just visible behind the tips of the GC), rather broad and dark blackish-brown. The ground colour of the SS is rather cold greyish-brown. [9119071]
1cy October (male). Uniformly juvenile SS, lacking moult contrasts. The SS shows five bars (and a sixth bar is barely visible behind the GC tips). The bars are medium brownish and rather narrow, and the ground colour of the SS is rather warm yellowish brown. [8095536]
1cy October (female), showing variation. [8095523]
2cy October (male). Birds with less extensive moult of remiges show moult contrasts in the arm. This bird shows a largely unmoulted arm, and most SS are worn and slightly bleached. These unmoulted SS are of typical juvenile type, showing five or six narrow bars, in contrast to the single adult type S (in the mid-arm) showing adult pattern with four broad bars. [9119076]
2cy November (female). Birds with less extensive moult of remiges show moult contrasts in the arm. This bird shows a largely unmoulted arm, and most SS are worn and slightly bleached. These unmoulted SS are of typical juvenile type, showing five or six narrow bars, in contrast to the single adult type S (in the mid-arm) showing adult pattern with four broad bars. [8094737]
2cy+ November (male). SS are uniformly post-breeding, showing no moult contrast (if a moult contrast is present, the age may be able to specify to 2cy or 3cy+). The SS show four adult type bars (a fifth bar is just visible behind the tips of the GC), rather broad and dark blackish-brown. The ground colour of the SS is rather cold greyish-brown. [8095503]
2cy+ November (female), showing variation of the adult pattern in the warmer coloured female wing. [8099937]
More Asio otus:
Sexing autumn and spring
Ageing spring

Moult
Ringers' DigiGuide main page
Ringers' DigiGuide is sponsored by:
[Not showing? Disable adblocker for this site.]
 

Ringers' DigiGuide - main page