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Auteur Topic: Vreemde Gans  (gelezen 314 keer)

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J&L

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Vreemde Gans
« Gepost op: augustus 05, 2009, 18:58:24 pm »

Hoi,

Welke gans is dit?
Gelogd

gjcaspers

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Re: Vreemde Gans
« Reactie #1 Gepost op: augustus 05, 2009, 19:05:53 pm »

Lijkt mij Indische x Canadese. Mogelijk Kleinste Canadese, want de vogel lijkt wel erg donkerbruin en kortsnavelig.

In tegenstelling tot deze http://forum.waarneming.nl/smf/index.php?topic=85218.0 lijkt het wit hier wel op de goede plaats aan de hals te zitten, nl. aan de zijkant.
« Laatst bewerkt op: augustus 05, 2009, 19:13:13 pm door gjcaspers »
Gelogd
Groet,
Gert-Jan Caspers

J&L

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Re: Vreemde Gans
« Reactie #2 Gepost op: augustus 05, 2009, 19:18:05 pm »

Hoi,

Bedankt voor de reactie.
Deze stond tussen de Brandganzen maar 10KM hiervoor kwamen we twee Indische ganzen tegen die tussen de Canadese ganzen stonden dus dat kan wel.(zie foto)
Wat mij opviel bij de Hybride was de kleur en maat van de poten en de korte snavel.

ps.Brandgans X Indische kan dat ook nog?
« Laatst bewerkt op: augustus 05, 2009, 20:11:01 pm door J&L »
Gelogd

Alcedo atthis

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Re: Vreemde Gans
« Reactie #3 Gepost op: augustus 10, 2009, 15:02:05 pm »

I think it is probably  barnacle x barheaded , although it looks very brown on first glance
But there is a faint border between darker breast and lighter flanks and the bill is on the short side.

see some examples here:

http://www.flickr.com/groups/hybridbirds/discuss/72157604663060605/?search=hybrid+barnacle+goose
Gelogd
greetings,
Jörn Lehmhus

gjcaspers

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Re: Vreemde Gans
« Reactie #4 Gepost op: augustus 10, 2009, 19:27:31 pm »

How could a Barnacle x Bar-headed hybrid ever be that brown? Would't Cackling Branta hutchinsii minima x Bar-headed offer a better explanation for the deep brown colour and short bill?
Gelogd
Groet,
Gert-Jan Caspers

Alcedo atthis

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Re: Vreemde Gans
« Reactie #5 Gepost op: augustus 11, 2009, 09:31:07 am »

I can not exclude a hybrid minima  x barheaded,

but barnacle x other geese sometimes can be astonishingly brown, especially in summer. This can apply to barnacle x barheaded, but also to Barnacle x snow.
Maybe this is some kind of bleaching?
« Laatst bewerkt op: augustus 11, 2009, 10:45:12 am door Alcedo atthis »
Gelogd
greetings,
Jörn Lehmhus

gjcaspers

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Re: Vreemde Gans
« Reactie #6 Gepost op: augustus 12, 2009, 11:38:13 am »

Interesting! The only Barnacle x Bar-headed hybrid that I have observed all year round, during many years, never showed any brown in any season.
Gelogd
Groet,
Gert-Jan Caspers

Alcedo atthis

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Re: Vreemde Gans
« Reactie #7 Gepost op: augustus 16, 2009, 10:58:12 am »

Well, your suggestion of minima involvement could well be the correct one. This is indeed very brown.

But it is not so that only hybrids with canada or cackling can show brown.

I tried to find some of the pictures where hybrids barnacle x barheaded looc more brownish, but didn´t find them. these are more grey than the bird in question, but still show some brown coloration on a dark breast.

http://www.flickr.com/groups/hybridbirds/discuss/72157604663060605/?search=barnacle+goose

however , that is not the extreme i wanted to show.


In this respect this barnacle x snow goose hybrid is also interesting, as we (at least I ) thought of canada x snow when seeing this first. due to the very brown coloration

http://www.flickr.com/groups/hybridbirds/discuss/72157606470242798/?search=barnacle+goose

but this is a bird where the parentage had been documented-snow x barnacle goose.

Look at vthe wing coverts of the bird flying ---very barnacle-like.
snow x canad or snow x barnacle seems tto be quite tough to ID  sometimes (or maybe even impossible)
« Laatst bewerkt op: augustus 16, 2009, 11:01:00 am door Alcedo atthis »
Gelogd
greetings,
Jörn Lehmhus

gjcaspers

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Re: Vreemde Gans
« Reactie #8 Gepost op: augustus 17, 2009, 19:27:26 pm »

And here I thought that phenotype in hybrid geese is determined by simple rules, like "brown is always dominant over grey", so a brown bird can't have two non-brown parents... not so, apparently...
Gelogd
Groet,
Gert-Jan Caspers

Alcedo atthis

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Re: Vreemde Gans
« Reactie #9 Gepost op: augustus 18, 2009, 08:52:42 am »

As far as I know there are , broadly speaking, two types of melanin,  Eumelanin ( for blackish -grey colorations) and Phaeomelanin (for brownish colorations)- so if the birds have both types expressed, this wouldn´t be allways obvious- for example if in the black breast of barnacle goose both Eu- and phaeomelanin are expressed you wouldn´t see the brown phaeomelanin...
Does that theory make sense????
Gelogd
greetings,
Jörn Lehmhus

gjcaspers

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Re: Vreemde Gans
« Reactie #10 Gepost op: augustus 19, 2009, 13:38:15 pm »

Hmmm, if a Barnacle Goose expressed phaeomelanin, it would be brown like a Canada Goose, I should think.

I would be thinking more along the lines of: expression of phaeomelanin requires the actions of gene A and gene B. Barnacle Goose has a functional gene A but not gene B; Snow Goose has a functional gene B but not gene A. The hybrid would have a functional copy of both gene A and gene B, and would express phaeomelanin.

But I'm just making this up. I will have to read up on tne biosynthesis of melanins... some day, when I can make the time...
Gelogd
Groet,
Gert-Jan Caspers

Alcedo atthis

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Re: Vreemde Gans
« Reactie #11 Gepost op: augustus 19, 2009, 14:44:00 pm »

I was thinking alonng the lines : maybe barnacle goose expresses some phaeomelanin, but at body places where you do not see it?
Anser indicus at least seems to express some phaeomelanin at the rear flanks:

http://www.gartenspaziergang.de/wasservogel/t_streifengans.html

maybe that could be sufficiuent...

but it is all speculation...
Gelogd
greetings,
Jörn Lehmhus

J&L

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Re: Vreemde Gans
« Reactie #12 Gepost op: augustus 25, 2009, 19:29:39 pm »

Hoi,

Ik heb al moeite met de Nederlandse vogel namen en nu óók nog de Engelse :rolleye:
Hier nog een foto.Het was af en toe bewolkt en dan weer fellezon dus vandaar de kleur.
« Laatst bewerkt op: augustus 25, 2009, 19:31:34 pm door J&L »
Gelogd

Alcedo atthis

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Re: Vreemde Gans
« Reactie #13 Gepost op: augustus 26, 2009, 17:06:16 pm »

http://community.webshots.com/photo/fullsize/1124340792042687404TXQRmA

This seems to be a fairly similar bird, but on your bird there is a slight contrast between breast and flanks,
with the breast being darker.

I see on your second photo the legs and belly of anmother goose, looks like it could be Canadese gans. Can you confirm that?

or was this bird only with Brandgans  ...or with which other species?
« Laatst bewerkt op: augustus 26, 2009, 17:09:39 pm door Alcedo atthis »
Gelogd
greetings,
Jörn Lehmhus

J&L

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Re: Vreemde Gans
« Reactie #14 Gepost op: augustus 26, 2009, 17:41:15 pm »

Hoi Jörn,

Zoals ik al eerder schreef:
Deze stond tussen de Brandganzen maar 10KM hiervoor kwamen we twee Indische ganzen tegen die tussen de Canadese ganzen stonden dus dat kan wel.(zie foto)
Wat mij opviel bij de Hybride was de kleur en maat van de poten en de korte snavel.

Ja de Gans op jouw foto lijkt echt op die van mij.
Gelogd
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