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Northern Long-tailed Tit A.caudatus (1 Viewer)

rupicola

Amigo de los Psittacidos
Netherlands
I could use some help on determination of Aegithalos caudatus caudatus.
the Northern Long-tailed Tit.

I would like to get some information on the differences
between cautatus and europaeus and especially the colour of the head,
which is obviously white in caudatus, but how about the ground colouration?
Are the head feathers all white (from basis to top) or
do they have a darker basic colouration and only white to the top of the feather?

please help me out!
 
hannu said:


Thanks for your help Hannu.

the first three photos are caudatus to me the fourth photo appears to show
a (dark) europaeus.

The problem is that I caught a caudatus which appears like the three photos above, It had a snowy white head and breast but a darker ground colouration underneath the white headfeathers. Therefore I was told this bird is no caudatus?

So I would like to ask the North European birdringers, who are likely to be more experienced with this species, their opinion about this.
does caudatus have totally white feathers without a darker basis or do these birds have white feathers on their head and breast with a slightly darker basis?


w.k.r.

Rupicola
 
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You must remember that both the range of caudatus and the range of europaeus overlap, so probably it's possible to see 'hybrids' of these two subspecies. I have obs from breeding pair in Hungary, where one was caudatus and other was europaeus.

Do you have sure that that colour of bird's belly was real (therefore it was not dirty) ?
You bird sounds so caudatus otherwise!

Pure(?) caudatus has white underside, breast and head as you will see in the pictures.
Sometimes it's possible to see some kind of brown nuance in the flanks.

I think that hybrids are more common in somewhere Baltic Countries and southward.

Cheers,
Hannu
 
Actually, the Long-tailed we caught in this case was a male in company of a europaeus female.

Its head and breast was snowy white as shown on the photos you added,
but underneath the white, just above the skin there was a darker (ground)colouration.
In other words these feathers were not pure white all the way towards the skin but they do appear white from the outside.

So I say we caught a caudatus, but I was told that a real caudatus
has exclusivly all white feathers on its head and breastparts and no darker ground colouration underneath when one blows up the feathers.

In my opinion pure white feathers, without any trace of pigmentation,
are only found on albino's or am I wrong here?

also in my opinion caudatus x europaeus does (always?) show some dark brownish spots on the head and therfore these Hybrids obviously do not appear to be pure white headed and white breasted.

cheers

Rupicola
 
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I suppose that your bird is caudatus or at leats it reminds caudatus, even it has some kind of figures on the white area.
If I understand in a right way, the proximal part of feather can be darker (thus different colour) than the top of feather. In my opinion, this is quite common phenomenon in different species. Also in caudatus, we have seen also very small dark scratches in the white area and it probably is only variation of the caudatus. I don't know what is the situation of subspecies now, but Svensson mention
many subspecies to Long-tailed tit, which may be a rather difficult to identify in fact.
Did you measure the wing ?

Hannu
 
rupicola said:
Actually, the Long-tailed we caught in this case was a male in company of a europaeus female.

Its head and breast was snowy white as shown on the photos you added,
but underneath the white, just above the skin there was a darker (ground)colouration.
In other words these feathers were not pure white all the way towards the skin but they do appear white from the outside.
Rupicola

I know nothing about LTT. However your description reminds me of the wear we see so clearly in birds like brambling and reed bunting. The winter (non-breeding) colouration is on the tips of the feathers. This wears off to reveal the breeding colouration which has been hidden underneath all the time.

What would your LTT look like with a little more wear ? Would it still be showing white or would it have reached the darker colouration ?

Mike.
 
Hi Rupicola-

Here in the Czech Republic, we have both caudatus and europaeus and their hybrids.

The bird in the pictures below was photgraphed earlier this spring in Prague. I assumed the bird was a hybrid, due to the blackish ground color on the head. However, I'm not sure if the fact that it was still retaining some juvenile plumage above the bill only serves to confuse the issue.

-Adam
 

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Blackstart said:
Hi Rupicola-

Here in the Czech Republic, we have both caudatus and europaeus and their hybrids.

The bird in the pictures below was photgraphed earlier this spring in Prague. I assumed the bird was a hybrid, due to the blackish ground color on the head. However, I'm not sure if the fact that it was still retaining some juvenile plumage above the bill only serves to confuse the issue.

-Adam

It would be difficult to say from your birds , does it c X e hybrid or not ?
If blackish colour (quite small area in the front of eye) on the head is the only difference from caudatus, I would say, it's still caudatus. Probably caudatus in southern area is more dirty looking (especially white areas) as it's in the northern areas.

Many times these hybrids have obviously many characters from both of (sub)species. But I don't know how researchers specify hybrids ! If c X e hybrids can get nestlings, the colour variation will increase due to descendants of hybrids.
 
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Hi everyone,

I first had to figure out how to get my photo attached

but

here is the little guy I'm talkin' about!
 

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long-tailed tits

Hi hannu,
What do you make of these two birds,they were caught together,at a coastal bird observatory on the north sea coast,in the UK....WOULD LIKE YOUR OPINION PLEASE!!!


Mark
 
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marky boy said:
Hi hannu,
What do you make of these two birds,they were caught together,at a coastal bird observatory on the north sea coast,in the UK....WOULD LIKE YOUR OPINION PLEASE!!!


Mark


Hi Mark !

Thanks on your confidental ;-)

In my opinion, the bird with dirty white head has probably some kind of influence of caudatus, because it has weak lateral crown stripe (only 'early stage'). The bird reminds in dominant colour more europaeus/rosaceus than caudatus. On the other hand, 'interior' variation of subspecies is not so well-know.
Scapulars is totally reddish brown as the europaeus/rosaceus does (caudatus has white in the 'under part' of scapulars). The bird has also reddish colour also in tertials (caudatus has not reddish colour in the tertials, only black & white) > see
http://www.tarsiger.com/images/masa/Aegcau03.jpg
The second bird is europaeus or British ssp rosaceus (Svensson).
Effectively both subspecies and their variation are not so well-known.

Hannu
 
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Hi Hannu,

thanks for your reply,very kind of you....i thought the same,that is was an intergrade,from belgium perhaps or slightly further east.When we first inspected the paler-headed individual, continental long-tailed tit came to mind.it had a wing of 94mm.They were ringed on the 17th of april 2004 and the length of the wing indicated they were both males.
It was a good bird for the observatory,as it was the first long-tailed tit ringed of probable 'continental origin'.we do get the british 'rosaceus' from time to time,but not very often at all.but nothing like the paler-headed bird.
Thank-you for your opinion.

kind regards
mark
 
marky boy said:
it had a wing of 94mm.

Mark,
are you sure, that wing was 94 mm ? You probably meaned 64 mm ?
You should remember also that sometimes you can get individual, which overstep the Svensson's limit.
 
Hi Hannu,

had a busy day yesterday, and was very tired, and now feeling very foolish,!!!. i did mean a wing of 64mm not 94mm !!!,that would be one big long-tailed tit. Sorry about that everyone!!!,mistakes do happen.And yes hannu,we did realise that some birds do overstep the limit on wing length,and 64mm is quite long for a british bird.but there is overlap between wing lengths of intermediates.My guess is that the paler-headed individual is more likely from the hybridization zone,roughly between holland and the ukraine.Thanks for your opinion hannu.


mark
 
marky boy said:
My guess is that the paler-headed individual is more likely from the hybridization zone,roughly between holland and the ukraine.Thanks for your opinion hannu.

mark

I suspect the hybridization zone may be somewhat north of this line as the birds I see in this part of Denmark are a mix of very white-headed birds (presumably caudatus) and dark-headed birds (presumably europaeus) as well as intergrades between the two forms.

Cheers,

Stuart
 
Good god - lotti's with 94mm wings eh - I've obviously been missing something for years!

Hi guys - I know what you mean about the identification problems, they can be a bit tricky especially where they start to mix. By the way, rupicola, I'd say your bird was a caudatus. I'm working on the lottis up in Estonia at the moment and they are about as white-headed-caudatus-like as they come!

I am doing PhD research on long tailed tits at the moment and I am looking for a bit of help myself from people just like you!

If you have found a long-tailed tit nest this season (there's still time!) or at any point in the past then tell me about it. I have a short questionnaire that you can fill for each nest just concerning its site and a bit about the birds that were hanging around. Attached should be a word document highlighting all of this.

Please give it a look and help me out if you can. You could be contributing to part of a really cool worldwide data set.

Oh the power of science and birding combined - I can think of nothing better!

Cheers all,

Beth

PS- want more information? email me [email protected]
 

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I'm also looking for caudatus biometric data to compare with europaeus data.
Who can help me out?
 
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