White-faced heron - unusual shaped bill

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Paul Gibson
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Joined: Tue Jul 30, 2013 9:49 am
Location: Whanganui

White-faced heron - unusual shaped bill

Postby Paul Gibson » Thu Apr 09, 2020 6:27 pm

This picture was sent to me from a friend at Bell Block, Taranaki, of a white-faced heron with an unusual shaped bill. The bird was with other WFH in trees on the coastal walkway, near the end of Mangati Road, Bell Block, right near the coast, in case any birder lives nearby and wants to check it out.

http://www.upics.co.nz

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Raewyn
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Location: Te Puke
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Re: White-faced heron - unusual shaped bill

Postby Raewyn » Fri Apr 10, 2020 6:26 pm

Thanks. That's interesting. I saw one with a similar crossed bill at Whakatane in December 2014. Could it be a congenital deformity or possibly an injury?
Finn Davey
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Re: White-faced heron - unusual shaped bill

Postby Finn Davey » Fri Apr 10, 2020 10:32 pm

It would just be a deformity caused by a mutation in the DNA base sequence, that's what causes most bill deformations in birds. They usually get along with life just fine though.
Paul Scofield
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Re: White-faced heron - unusual shaped bill

Postby Paul Scofield » Sat Apr 11, 2020 6:19 am

Such deformaties are no longer thought to be due to genetic mutation. It maybe due to to developmental issues such as brief cooling of the egg - alternatively this may be a case of Avian keratin disorder (AKD), characterized by unusal bill growth and caused by a Picornavirus. See https://mbio.asm.org/content/7/4/e00874-16

P
Raewyn
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Location: Te Puke
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Re: White-faced heron - unusual shaped bill

Postby Raewyn » Sat Apr 11, 2020 9:55 am

Thanks Paul. That's a very interesting article. I have fished out the photos I have of the Whakatane bird. It was at Sullivan Lake on 27/12/2014 and was not quite fully fledged. I thought it does look similar to the example in the article's photos - a bit more extreme than the one at Bell Block in the post above but not as long as the photos in the article (given that it's a longer bill anyway). Is this something else we should look out for more of? The bird seemed happy enough at the time but I never saw it again. Here's a heavily cropped view of the bill.

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chris
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Re: White-faced heron - unusual shaped bill

Postby chris » Sat Apr 11, 2020 10:33 am

I would have thought the most obvious cause would be pesticide or chemical poisoning in its environment or food chain.. sometimes the most obvious things are hardest to accept. You talk like experts but your scope of possibilities seem thin. Haven't these kind of deformities, not mutations, recently been seen the world over.or am I making this up.
Paul Gibson
Posts: 263
Joined: Tue Jul 30, 2013 9:49 am
Location: Whanganui

Re: White-faced heron - unusual shaped bill

Postby Paul Gibson » Sat Apr 11, 2020 12:14 pm

Thanks Raewyn for adding extra photo of similar bird, this has generated some interesting discussion.

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