Swift Parrot bill colour

[Debbie Saunders <>]

Hi Geoffrey,
Likewise I am also very interested in the bill colour changes and noted some of the dark beaks in the great photos that have been posted.

I find it particularly interesting in that a previous physiological study on swift parrots by Brett Gartrell suggests that swift parrots don't physiologically prepare to breed until they get back to Tassie however I think that the change of bill colour indicates that at least some birds do prepare for breeding before reaching nesting areas.  I think my colleagues who work on the species in Tassie said that they mainly see black/grey bills during the breeding season and the chicks have yellowish bills so perhaps the colour change is more pronounce in the wild than it is in captivity.

In relation to the observations of juvenile birds this month I was wondering if these birds may be dull females since most birds should have adult plumage by this time of the year.  I have found the most definite way to id a juvenile bird if the plumage is uncertain is to check out the iris colour - juveniles have a darker iris that is brown in colour whereas an adult has a yellow iris - however of course there are always all the colour gradations inbetween to keep us all on our toes.

Since I have colleagues from Tassie arriving in Canberra tomorrow I was planning on showing them the birds here - can anyone confirm they are still around?  Based on past visits I expect they will be leaving town again any day now.
Cheers Debbie

---

From: Geoffrey Dabb <>
To:
Sent: Mon, 20 September, 2010 1:36:34 PM
Subject: [canberrabirds] Swift Parrot bill colour

Having been interested in this for some time, I have prepared the enclosed notes with my thoughts, and would be happy to receive any comments.  I have spared you the photos but could send them on request.  Once again, the same bill can appear to vary in shade markedly according to light, use of flash etc

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