Grey Shrike-thrush - sexual dimorphism, or juvenile markings?

["Denis Wilson" <>]

Hi Coglisters

 

Is it possible to distinguish male and female Grey Shrike-thrushes by plumage?

 

I found this injured bird on the road, on the weekend. Naturally I took a photo.

I was intrigued by the fine dark lines on the centres of the chest feathers.

 

On line sources (COG gallery, Australian Museum Birds in backyards) make no mention of sexual dimorphism. However, clearly some birds in the COG gallery have much whiter faces, and smoother chest colouring than this bird.

 

This bird has just the faintest of brown eyebrow markings (trace of juvenile plumage?). The base of the lower mandible, is grey, not the typical yellow gape of a recently fledged bird. 

 

Some photos show clear black beaks, and very smooth, pale grey chests, and white lores and throat. I take those markings to indicate male birds.

 

Any clues as to whether this is a female, or nearly mature juvenile bird?

Grateful advice, please.

---

Incidentally, as the bird was stunned, (when I found it) but apparently structurally intact, I released it, after keeping it calm for some time. It had recovered to the point of hopping actively, but still not flying. I hope it recovered, but I felt I had little alternative to let it take its chances.

 

Cheers

 

Denis
www.peonyden.blogspot.com

 

Love to Grow: Grow to Love

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