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is this a greenish warbler (1 Viewer)
- Thread starter neil w
- Start date
Winterdune
Well-known member
For info Garden Warbler is a lot bigger and scarcer than Chiffchaff.
JayFeatherPL
Well-known member
Greenish warbler would show whitish underside (with a hint of yellow on the throat and the breast), evident long whitish supercilium with a dark eyestripe below (but the eystripe isn't very distinct), blurred and whitish stripe on the wing and a big head with a high crown.
I hope it helped, cheers
I hope it helped, cheers
JayFeatherPL
Well-known member
Actually greenish warbler (because the OP was asking about the greenish warbler, not the garden warbler) is about the same size of the chiffchaff and it's even slightly smaller (9,5 -10,5 cm vs 10-12 cm). Garden warbler on the other hand is a Sylvia species (not a Phylloscopus, like a chiffchaff or a greenish warbler) and it also isn't a lot bigger than chiffchaff because it measures 13-14,5 cm (so it's only slightly bigger).
Cheers
Richard Dale
Well-known member
In defense of Butty, the OP did ask about garden warbler, and I'd argue that in relative terms garden warblers are a lot bigger than chiffs. They may only be a couple of centimetres longer but that's around 25% - if someone were 25% taller than my 6' 2" they would be around 7' 8" and I'd say you'd find that pretty noticeable. Garden warblers are also at least double the weight of the average chiff.Actually greenish warbler (because the OP was asking about the greenish warbler, not the garden warbler) is about the same size of the chiffchaff and it's even slightly smaller (9,5 -10,5 cm vs 10-12 cm). Garden warbler on the other hand is a Sylvia species (not a Phylloscopus, like a chiffchaff or a greenish warbler) and it also isn't a lot bigger than chiffchaff because it measures 13-14,5 cm (so it's only slightly bigger).
Cheers
JayFeatherPL
Well-known member
(By they way I replied to Winterdune, not Butty, so you don't have to defend Butty!). I agree, and I wrote that garden warblers are "slightly bigger than chiffchaffs" (not a lot bigger, like Winterdune said), but this difference isn't big enough to separate the chiffchaff from the garden warbler looking at the bird's size only, because it's impossible to estimate if the bird is 1 cm bigger of 1 cm smaller, especially if the bird is alone! (and you almost always see lonely birds) + there's a mutual range and chiffchaffs can be the same size as the garden warbler. One more thing: if we took the smallest chiffchaffs (10 cm) and the biggest garden warblers (14,5 cm) there would be only 4,5 cm difference, so still, it's not a great difference to ID the bird by this feature only (remember that on average chiffchaffs are bigger and garden warblers are smaller so their lenght can overlap or the difference is impossible to see without a ruler).
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Richard Prior
Halfway up an Alp
JayF, you state :
"One more thing: if we took the smallest chiffchaffs (10 cm) and the biggest garden warblers (14,5 cm) there would be only 4,5 cm difference, so still, it's not a great difference to ID "
I'm not the world's best at Mathematcis but 4,5cm added to 10cm sounds like almost 50% bigger to me!
You are right about the difficulty of estimating the size of a single bird (Butty's Law I think it's called) though I'm sure I'm not the only birder who finds a bit of knowledge about trees and bushes is handy when faced with a solitary bird, ie, size of leaf etc., but maybe I am the only one
"One more thing: if we took the smallest chiffchaffs (10 cm) and the biggest garden warblers (14,5 cm) there would be only 4,5 cm difference, so still, it's not a great difference to ID "
I'm not the world's best at Mathematcis
but 4,5cm added to 10cm sounds like almost 50% bigger to me!You are right about the difficulty of estimating the size of a single bird (Butty's Law I think it's called) though I'm sure I'm not the only birder who finds a bit of knowledge about trees and bushes is handy when faced with a solitary bird, ie, size of leaf etc., but maybe I am the only one
Richard Dale
Well-known member
Sorry, you're correct, Winterdune rather than Butty. However, I disagree with the rest of your post: even the largest chiff is never as big as the smallest garden warbler, their length and wing length measurements do come close to overlapping and the difference in mass is always pronounced. Garden warblers appear larger, bulkier and (when alive) slower moving than chiffs. The largest male chiffs, loaded with fat for migration, can weigh as much as 10 g, but birds as heavy as this are extremely rare and the majority weigh 6.5–8.5 g. The smallest GW might weigh around 13 g, if in poor condition, but the vast majority weigh around 15–18 g, getting up to 20+ when they're really packing on the fat prior to migration.
I didn't recommend looking at a bird's size alone, and obviously there are numerous plumage and structural differences between the two, but your quoted 4.5 cm difference is getting on for half the length of many CCs, and therefore a pretty significant and obvious difference (especially when you have the bird in your hand, as with the unfortunate subject of the thread). My argument is simply that if a bird is 25% to 45% larger (longer) than another, as well as at least double, and at the extreme ends of the scale up to triple the weight, the difference should be pretty apparent, particularly for such small birds. At the smaller end of the avian scale, field impression changes quite dramatically with size, and particularly mass.
Would you say a kingfisher is a similar size to a garden warbler? They are only about 25–50% longer than garden warblers, but they weigh around 35–45 g, well over double that of most garden warblers. Despite being only slightly larger using your rationale, they give a much different impression of size, both in the field and in the hand, because of their greater mass, just like garden warblers with respect to chiffchaffs. Going the other way, how about goldcrests? Goldcrests are about 9 cm long, so only slightly smaller than many chiffs, but weigh just 5–6 g and give a field impression of a much smaller bird than most chiffs.
I didn't recommend looking at a bird's size alone, and obviously there are numerous plumage and structural differences between the two, but your quoted 4.5 cm difference is getting on for half the length of many CCs, and therefore a pretty significant and obvious difference (especially when you have the bird in your hand, as with the unfortunate subject of the thread). My argument is simply that if a bird is 25% to 45% larger (longer) than another, as well as at least double, and at the extreme ends of the scale up to triple the weight, the difference should be pretty apparent, particularly for such small birds. At the smaller end of the avian scale, field impression changes quite dramatically with size, and particularly mass.
Would you say a kingfisher is a similar size to a garden warbler? They are only about 25–50% longer than garden warblers, but they weigh around 35–45 g, well over double that of most garden warblers. Despite being only slightly larger using your rationale, they give a much different impression of size, both in the field and in the hand, because of their greater mass, just like garden warblers with respect to chiffchaffs. Going the other way, how about goldcrests? Goldcrests are about 9 cm long, so only slightly smaller than many chiffs, but weigh just 5–6 g and give a field impression of a much smaller bird than most chiffs.
JayFeatherPL
Well-known member
I completely didn't think about the bird's mass which is important as you said...now, I agree with you, I see that you can't look at the bird's lenght only...(I looked at the lenght in the Collins guide, where there is no the bird's mass)
Richard Dale
Well-known member
Weight is used here as an easily comparable substitute for general size and bulk. Birds of similar size but differing weight can give very different impressions in the field - the reason GW looks like a larger, slower, more robust bird than a CC is not just because it is fractionally longer, but because it is a much bulkier bird - comparison of their respective weights is just a convenient way illustrating this. Also, the bird in the OP was not in the field, and difference in size/weight/mass between CC and GW is very apparent in the hand.
Except that it isn't - in my opinion. If you mean bulk, then call it bulk - but never weight or mass. Migrating birds put on weight - loads of it - but it's never visible - it may be apparent to a ringer with the bird in the hand but never to a field birder. So weight per se simply isn't a useful practical ID feature.
JayFeatherPL
Well-known member
I agree with Butty, if two birds (lets say we don't see the plumage details/colours) are the same size, but one bird is heavier, you can't tell the difference between them!
Richard Dale
Well-known member
No one is saying weight in and of itself is a useful ID feature, just as no one is expecting you to measure the length of a bird in the field. However, while I can't make an easy comparison of the 'bulk' of two similarly sized birds without getting into the use of subjective language, I can do so by using their relative weights as a proxy: bulkier birds are heavier. Would you say a wren and a goldcrest, birds of broadly equivalent length, wing length, etc., give the same field impression? Or would you say the goldcrest, that weighs about half that of the average wren, gives a far less bulky impression, easily detectable in the field via its movements and behaviour? How about a blue tit and a chiffchaff? Similar total length and wing length, but quite different field impression, as blue tits are 50–100% heavier.
In combination with other anatomical variables (particularly wing length), the weight of a bird affects how it moves - hence the garden warbler's slower, more deliberate movements in comparison to the much flightier, more athletic chiffchaff. Again, I was simply using the clear and comparable weight measurements available to illustrate one reason why a garden warbler appears noticeably larger than a chiffchaff, despite only being about 25% longer.
I would also argue that birds heavily laden with fat can sometimes be noticeable - for example, a sedge warbler fully loaded can in rare cases get up towards 18–19 g (the normal weight range is 10–13 g) and appear barely able to get off the ground, with noticeably more sluggish movements than a 'clean' individual (you try running about the place with a backpack weighing half your bodyweight on your back).
I'm not talking about minor differences here, but when the differences are large, such as in the cases illustrated above, differences in relative bulk (to reiterate, with weight used here as a proxy to illustrate my point) are apparent to the observer and form a small part of the toolkit available to a birder in reaching an identification.
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But getting into subjective language over 'bulk' is precisely and necessarily what you should be doing. Weight does not work as a proxy for field use.
I fear you've missed this (my only) point - perhaps because I (wrongly) felt it was obvious and so preferred not to elaborate. I should have gone on more...
In general, you are attempting to equate length and weight as two comparably-useful means of comparing - by measurement - birds' sizes - and they just are nowhere near being either comparably precise or (even more importantly) comparably useable. In my view, they are so nowhere-near comparable that attempting to quantify comparisons of bulk by means of weight is lacking in rigour and precision to such a degree that it's confusing and ambiguous to the point of being useless. Descriptive qualitative comparisons, on the other hand, absolutely are useful.
Reasons:
1. Weight is hugely more variable than length.
2. Everyone can get something definite by being told that one bird is 50% longer than another (based on length measurements). But... being told that one bird is 50% more bulky than another (based on weight measurements) - what on earth does that mean?! No two people will have the same way of assessing 'bulk' visually - and a scheme for quantitative comparison of size has to have capability for visual assessment in the field or it's worth nothing.
So... definitely find words for qualitative descriptions and comparisons of bulk - but doing it numerically based on weight will just confuse the bejesus out of people through its inevitable inconsistency and ambiguity.
In my opinion.
Richard Dale
Well-known member
Am I? I think this very much depends on the comparison being made. In some cases weight is much more useful - for example, long-tailed tits are about the same length as great tits, and magpies are longer than woodpigeons, but I think we know in each case which is the bigger beast.
I'll try to make my point more clearly. I initially posted to back up Winterdune's assertion that GW are "a lot bigger" than CC, and pointed out that the difference in length that was quoted by JayFeatherPL was not in fact a small difference, but that it should be quite noticeable (using me standing next to a nearly eight foot human as an example), even allowing for your eponymous law and particularly where the subject bird was in fact laying dead next to a ruler. The initial comparison of weight between the two species was a brief aside, pointing out that GW is typically double the weight of CC - the implication being that heavier things tend to be bigger in more dimensions than just length.
I'm not suggesting, for a second, that one should think about a bird's weight in the field when considering an identification - why on earth would you? Nor is the appearance of 'bulk' always helpful, particularly as birds can alter their appearance, sometimes quite dramatically, by raising and lowering feathers. Instead I reference the speed of a bird's movements, its general character and appearance, etc. as the things we notice in the field - garden warblers move more slowly and deliberately than chiffs, they do not flit about energetically or hover below foliage, they don't tend to chase after insects in flight. There can be various reasons for this, but one of them, particularly with ecologically similar species (small insectivorous warblers in this case), is that one is larger and therefore heavier than the other. Importantly, however, we are not currently in the field. In this case, musing over the differences between the two species while sitting at my desk and failing to do something more productive, I use weight as a freely available, well studied biometric that allows easy comparison between species, to help illustrate the size difference between the two species, and the fact that bigger birds are usually also heavier birds and, as a consequence, tend to display certain characteristics compared to similarly-sized but lighter birds.
In the latter part of your post you seem to be suggesting that measurements are somehow more confusing than qualitative descriptions and comparisons. What is so confusing about saying a typical garden warbler is about 25–50% longer and over double the weight of an average chiffchaff? Seems perfectly clear and helpful to me. Something being a just couple of centimeters larger might not seem that much, but if you are told that it also weighs more than twice as much, that immediately gives a clearer impression of the size difference between the two. And why can't I use both, the qualitative to reinforce the quantitative and vice versa? They are not mutually exclusive.
You mean like "slower, more deliberate movements in comparison to the much flightier, more athletic chiffchaff", "noticeably more sluggish movements", "GW looks like a larger, slower, more robust bird than a CC", or even "try running about the place with a backpack weighing half your bodyweight on your back"? The weights are just there to back up these points and provide a reason why GW gives the impression, even when it is on its own and its size might otherwise be difficult to estimate, that it is a larger bird than a CC.
Or we can agree to disagree - an entertaining discussion, nonetheless.
