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Auteur Topic: boomkruiper or taigaboomkrupier?  (gelezen 1267 keer)

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batsvensson

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boomkruiper or taigaboomkrupier?
« Gepost op: april 25, 2013, 16:19:13 pm »

I never tried to id a tree creeper before so this is my first time trying make a distinction between taigabooomkruiper  (C. familaris) and booomkruiper (C. brachydactyla) and I feel a bit confused about it but based on the saw tooth shaped white marks present on the wings I would guess it is a C. brachydactyla, or perhaps the angle of the picture just fools me to believe they are saw tooth shaped...

http://adam.waarneming.nl/waarneming/view/75438084
identification uncertain Unidentified bird - Aves indet.
observed at 2013-04-22 Amsterdam - Beatrixpark
Photos:



Thanks in advance BAT Svensson
« Laatst bewerkt op: april 25, 2013, 16:34:41 pm door batsvensson »
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Guus Peterse

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Re: boomkruiper or taigaboomkrupier?
« Reactie #1 Gepost op: april 25, 2013, 16:34:57 pm »

brachydactyla is right.
Gelogd
Guus Peterse

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batsvensson

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Re: boomkruiper or taigaboomkrupier?
« Reactie #2 Gepost op: april 25, 2013, 16:41:33 pm »

Thanks a bunch but to learn to help myself in the future; what tell-tale did you use to identify the bird?

frankneijts

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Re: boomkruiper or taigaboomkrupier?
« Reactie #3 Gepost op: april 25, 2013, 16:50:27 pm »

BAT, the 'saw tooth shape' of the white markings is an unreliable character. The only really reliable way to ID the two treecreepers is to look at the way the different white markings overlap and the way the first ones (from below) are composed. Therefore these markings together are called "stairs" and the different parts "steps". The first step is on primary (p) 4 (always with familiaris, sometimes with brachydactyla) or p5 (often with brachydactyla). The fact that on your bird there is no step on p4 is in itself a good indication that this is a brachydactyla. This is further confirmed by the overlap of the steps on p8, p7 en p6: you can see on your picture that the overlap of step p8 over step p7 = (+/-) the overlap step p7 over step p6. With familiaris the overlap step p8 over step p7 is much larger than overlap step p7 over step p6. So brachydactyla it is....
Gelogd
Groeten,

Frank

"When logic and proportion have fallen sloppy dead...
Remember what the dormouse said: feed your head!"
Grace Slick in 'White Rabbit'

batsvensson

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Re: boomkruiper or taigaboomkrupier?
« Reactie #4 Gepost op: april 25, 2013, 23:55:27 pm »

Thanks for your answer Frank, but please bear with me for a moment while I try to get this straightened out.

I do get the technical part of your explanation. However, when it comes to the practical application I utterly fail; I am not even sure what white region we talk about anymore (is it the one I marked with a yellow circle?) and I am equal ignorant about how enumeration of wing feathers are done therefore I don't even know which feather P4 is, never less the others. Would you be so kind to please straighten out these things for me?

Btw, I have read your sticky thread from 2008 before I even posted my question, but I didn't get much wiser from it, rather more confused when trying to both understand the dutch and the technicalities of the problem at the same time. :(

frankneijts

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Re: boomkruiper or taigaboomkrupier?
« Reactie #5 Gepost op: april 26, 2013, 22:30:26 pm »

Hello BAT,

The ID of treecreepers should be focussed on that part of the whitish/yellowish wingbar which runs over the primaries 4 t/m 8 and is compared to a stairway (trapje). The different parts of it (each one on p4 t/m p8) are the steps (treedjes). Here, especially for you and other English speaking readers/users, a new and somewhat shorter version of post 133 of the sticky thread with a new photo:
A = Overlap step on p8 over step on p7 (see the corresponding numbers just below the 'steps')
B = Overlap step on p7 over step on p6
C = Step on p4 (p1 t/m p3 have no steps)
D = Hind toe
E = Hind claw

1. For brachydactyla (Boomkruiper): A = B or even A < B; C = often absent or very small but sometimes rather prominent and in that case the top is situated lower than or at most equal with the tops of steps on p5 and p6 (no 'cup'); E < D.
2. For familiaris (including macrodactyla and brittannica) (Taiga/Kortsnavelboomkruiper): A > B; C = always present (mostly prominent) and the top of it reaches higher than the tops of the steps on p5 and often also on p6, creating something like a 'cup'; E = D but often E > D.

Beware that only the combination of A/B and C is diagnostic for familiaris and in this species (and its subspecies) almost always present in this way. Brachydactyla is much more variable and cn show one of these characters (some individuals show A > B r even a 'cup') but never both! Also bare in mind that D/E is variable and in this respect only birds with very long r very short claws are distinctive in the field but lots of them are not. Always try to use it in combination with A/B/C.

Good luck with it!
« Laatst bewerkt op: oktober 05, 2013, 23:28:50 pm door frankneijts »
Gelogd
Groeten,

Frank

"When logic and proportion have fallen sloppy dead...
Remember what the dormouse said: feed your head!"
Grace Slick in 'White Rabbit'

batsvensson

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Re: boomkruiper or taigaboomkrupier?
« Reactie #6 Gepost op: april 27, 2013, 00:00:08 am »

Thanks a bunch Frank, I understand how, where and what to look for now (and what to try get pictures of next time I see a treecreeper;). Many thanks again. :)

Gerard

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Re: boomkruiper or taigaboomkrupier?
« Reactie #7 Gepost op: mei 31, 2013, 18:39:03 pm »

I presumed I saw an ordinary treecreeper today, but this post makes me doubt. Unfortunately the pics aren't all that sharp. Which one is it?

Gelogd

batsvensson

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Re: boomkruiper or taigaboomkrupier?
« Reactie #8 Gepost op: mei 31, 2013, 18:54:02 pm »

Hard to tell, but it seams as A = B to me....
« Laatst bewerkt op: mei 31, 2013, 19:00:16 pm door batsvensson »
Gelogd

frankneijts

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Re: boomkruiper or taigaboomkrupier?
« Reactie #9 Gepost op: mei 31, 2013, 20:25:34 pm »

Hello Anders,

'Your' bird is a Short-toed Treecreeper (C. brachydactyla). The top of the 'step' on p4 is equal to the tops of the steps on p5 en p6 (no 'cup') and furthermore A = B indeed.
Gelogd
Groeten,

Frank

"When logic and proportion have fallen sloppy dead...
Remember what the dormouse said: feed your head!"
Grace Slick in 'White Rabbit'

batsvensson

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Re: boomkruiper or taigaboomkrupier?
« Reactie #10 Gepost op: mei 31, 2013, 21:20:19 pm »

Would you say that that the mark on p4, C, is small on this bird? (And, if I understand right, on my original bird the mark on p4 seams to be non-present).

frankneijts

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Re: boomkruiper or taigaboomkrupier?
« Reactie #11 Gepost op: juni 01, 2013, 11:15:23 am »

Would you say that that the mark on p4, C, is small on this bird? (And, if I understand right, on my original bird the mark on p4 seams to be non-present).

I would say that on this bird the mark ('step') on p4 is rather prominent which is not very often the case in brachydactyla: more often it is small(er) or even missing. In familiaris it is (nearly) always prominent so "missing" in itself is a (very) good indication for brachydactyla. If not, especially when the mark is as prominent as in this bird, you will need to look at the other ID-features.
Gelogd
Groeten,

Frank

"When logic and proportion have fallen sloppy dead...
Remember what the dormouse said: feed your head!"
Grace Slick in 'White Rabbit'
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