Inland Thornbills
- Differences between plumages of old and young birds

Adult Inland Thornbill
- showing a smoky grey upper plumage, very fine white scalloping in its forehead, and a pure black bill

When catching birds on a recent trip to Charcoal Tank Nature Reserve as described in the previous two posts we caught several Inland Thornbills Acanthiza apicalis albiventris. The bird illustrated above was caught on an earlier trip during the breeding season and was confidently aged as an adult bird. Those illustrated below are young birds, hatched in the previous spring, i.e. about October/November 2013.

Face of 1st year immature Inland Thornbill (older?)

Face of 1st year Inland Thornbill (younger?)

The bird on the left is developing a dark grey crown, similar to the adult bird, but the scalloping on the forehead is still buff-coloured. The narrow buff tips creating contrast between the scalloping and background colour, although not as strong as on the adult bird.













The second young bird, left, has a pale green/grey crown and forehead, with broad buff tips to scalloping, creating less contrast between the scalloping and background colour.

Profile of 1st year Inland Thornbill (older?)

In profile, the developing grey on the crown of the first young bird shows the dark head with fine buff scalloping, concentrated on the lower forehead. It also has a dark bill, but not fully dark as in an adult, especially at the base of lower mandible

Profile of 1st year Inland Thornbill (younger?)

In profile, the second young bird has a paler head, with less contrast between the background colour and the buff-coloured forehead scalloping, which extends well above the eye. The base of bill is yellow/buff, and the rest of the bill is dark grey, not black as on an adult

Wing of 1st year Inland Thornbill (older?)

Although these birds were not of exact known-age, as they had not been trapped and marked before, it would seem that young Inland Thornbill plumage progresses from broad buff-coloured scalloping on the forehead, through fine buff-tips, to fine white-tips by the time they reach adulthood. And the crown changes gradually from greenish-grey to smoky grey over the first year.




The first-year birds also retained some of their first-grown flight feathers. The first (older?) bird had three old outer primaries, and the inner primaries were recently moulted and freshly grown.

Wing of 1st year Inland Thornbill (younger?)

The second of the young birds still had all of its first-grown primary feathers, from its juvenile plumage.

The combination of all these features support that the second young bird was younger than the first, but only the recapture of known-age birds will help to confirm these ideas.

How to age and sex Rufous Whistlers

Two Rufous Whistlers - but what age and sex are they?
Charcoal Tank, NSW. March 2010

I have recently been in correspondence discussing how to age and sex Rufous Whistlers Pachycephala rufiventris, so considering that they are one of the most widespread bird species in Australia, I thought I should post a simple guide to this dilemma. 

The problem arises from their plumage moult sequence over the first years of their life. For they take three years to attain full adult plumage, and during the first two years, the males and females are alike (to our eyes and criteria so far discerned). Do the birds know which sex each other is, I'm sure they do, so why can't we tell?

This is not a complete description, indeed there might be errors. However, during future banding trips, I hope to photograph birds of known age (from previously banded birds) and note details which will help to further understand how to age and sex these common birds. The page will then be updated as fits new points to consider.  

Juvenile Rufous Whistler
Charcoal Tank, NSW. January 2011

Juvenile (J) Rufous Whistlers are recognisable by their bright yellow gape, the skin at the base of their bill, light-coloured bill and heavily streaked breast. These are usually being closely attended by adult birds.

Eye - dark brown iris

Bill - pale grey upper mandible, pink/yellow/grey lower  

         mandible, orange yellow inside

Breast - buff and heavily streaked

Throat - grey streaked with dark grey

First-year or Immature  Rufous Whistler
Charcoal tank, NSW. Sept 2012

First-year (1 or 2-) birds, or immature, those in the first year of their life have a similar plumage to the juveniles and adult females. Also the sexes are indistinguishable. The orange/yellow inside of the bill is the most diagnostic feature when in the hand, but not so useful in the field. Then, the pale lower mandible below the darker, but not dark black bill is the best feature to look for.

Eye - brown

Bill - dark grey on top mandible, pink/brown lower mandible.

Breast - pale buff streaked with dark grey.

Throat - grey streaked with dark grey/black.

Adult female Rufous Whistler (3+)
Charcoal tank, NSW. Nov. 2012

Adult female (3 or 3+) birds can be recognised by their black bill, dark red iris and lightly streaked breast. Their throat is white rather than grey as in a first-year bird. However, second-year males (2), i.e. those more than one year since hatching, look very similar. Banded birds can be aged with reference to when previously caught, otherwise behaviour is perhaps the only clue to sex in the field. In spring and summer try to determine whether the bird is behaving like a male or female. And beware of this piece of confusing knowledge - male Rufous Whistlers (and females?) can breed in their second year while in sub-adult plumage or in that similar to females.

Eye - dark deep red

Bill - black top, lower, and inside, pale palate

Breast - light rufous streaked with dark grey

Throat - white, streaked with dark grey

Sub-adult male Rufous Whistler
Charcoal tank, NSW. Sept 2012

Second-year, or sub-adult male (2) i.e. those more than two years since hatching, but less than three. These birds show the beginnings of adult male plumage coming through the immature plumage which was similar to that of a female. A dark grey or black breast band spreads across the top of the breast, and black feathers come in around the face. The throat whitens and loses its streaks. And the iris is red, but not as bright as that in an adult male's eye.

Eye - dull red

Bill - black on top, lower and inside, pale palate

Breast - rich rufous, with narrow dark streaks, faint or

             incomplete breast band

Throat - white and lightly streaked, dark feathers

              around face

Adult male Rufous whistler
Charcoal tank, NSW. Sept 2012 

Adult male (3 or 3+) Rufous Whistlers are the easiest to identify, not only to species but to sex. They have a distinctive rufous breast, belly and undertail coverts, a bright white throat and a black breast-band with linked black feathering up the sides of the throat and across the face. The eye is bright red and the bill glossy black.

Eye - rich red iris

Bill - black top, lower and inside

Breast - rich rufous with a black breast-band

Throat - pure white