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Is this a sparrowhawk? UK (1 Viewer)

Debbie1905

Well-known member
Hi, I took this appalling picture this morning in Essex. I think it is a male sparrowhawk, but it seems to have a wide white mark across the back of the head. I can't find any pictures of other sparrowhawks with this marking. Can you help please? Many thanks in advance.
 

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Debbie1905

Well-known member
Thanks very much. The white patch was in all 3 pictures I took - of which the one I posted is the best! Thanks both of you for your confirmation.
 

PYRTLE

Old Berkshire Boy
Young sparrowhawks do show various white, cream markings on the nape as they age from a juvenile through to a mature breeding adult as Ken says.
P
 

P.Sunesen

Well-known member
Young sparrowhawks do show various white, cream markings on the nape as they age from a juvenile through to a mature breeding adult as Ken says.
P

Yes, juveniles have more white on the nape than adults, but I'm not convinced that this fact also implies that there's a significant difference between first adult plumage and subsequent ones in that respect. Please see my post below.

Peter
 
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P.Sunesen

Well-known member
This is my penny.

Sparrowhawks have two plumages, juvenile, until the bird starts moulting in May/June in its second calendar year when approximately one year old, and adult after the completion of this first total moult, usually finished by September/October.

Although some individuals, mostly females, do show very subtle differences from first adult plumage to later ones (in the former plumage they tend to show some narrow, paler edges on the smallest of the wing coverts, which is not usually the case in subsequent adult plumages) these do not include the white bases of a group of nape feathers, which is something ALL Sparrowhawks sport irrespective of age.

However, it's a fact that juveniles (to a variable degree) have far more extensive white on their napes than adults, in sync with the much more speckled and "untidy" head markings of this first plumage, with streaked, rather than uniform crown and ear coverts, and a far more pronounced whitish supercilium.

Contrary to this, the white on the nape of adult Sparrowhawks is (most often) restricted to the BASAL parts of the individual feather (particularly so in males, which on average also have a weaker, often non-existent whitish supercilium than females), so that it's ONLY when the feathers are RAISED (when the bird is totally relaxed and 'fluffed up' as the bird in the OP) that this white patch becomes visible.

This white flecked nape is believed to create a sort of "fake face" which comes in handy, in that it probably to some extent prevents attacks from predators that perceive the prey as FACING them, and that the prey consequently is fully alert and ready to dash off at any instant.

I'm not saying that intensive measurements of many thousands of skins couldn't possibly produce a very slight difference between first adults and older adults with respect to the widths of the white, basal parts of the nape feathers in question, but the logical response to such a claim would be:

How do you recognise first time adults from older adults in skin collections where only a microscopic fraction would be ringed birds, taking into account that many/most adult birds are impossible to place in a definite first-adult-plumage-bracket because the vague differences (as mentioned above) aren't a constant, particularly in males.

Furthermore Sparrowhawks are very 'orderly' in the sense that they tend to moult COMPLETELY (as opposed to, say, Goshawks) so that in by far the most instances, tell tale, unmoulted, juvenile feathers would be rare to find after October.

In sum, the variation of the extent of white on the (feather bases) of adult A. nisus makes it highly unlikely that this could ever be used to distinguish between first- and older adults both in the hand, in the field, or when viewing a blurred long distance photo of an individual first- or older adult Sparrowhawk with fluffed up nape.

PS I've now seen the photographic ringers guide to sexing/ageing Sparrowhawks in another recent thread here. Although generally instructive and easy to understand, my caveat is that individual variation renders some of the points less useful. One may, for example, quite often see juveniles which fall well outside their respective sex category regarding the type of markings/barring/spots on the underside of both body and wings. Furthermore there's no mention of the (uncommon) extremely dark ("dusky type") of juveniles (most often males), and the (quite common) very adult male like adult females such as this one:

http://www.netfugl.dk/pictures.php?id=showpicture&picture_id=15849

Peter
 
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ChrisKten

It's true, I quite like Pigeons
Hi Peter,

I have neither the experience nor good enough eyesight to dispute any of what you typed above.. some useful info there. I'm also aware that your knowledge of Birds' plumage is second to none in this forum ;)

The .pdf I posted is just a guide that I feel might help answer some (not all) of the questions that many seem to have about these birds. My only experience of Sparrowhawks is of seeing different individuals for many hours at close range each year and throughout the year - it's their behaviour that interests me rather than their appearance, although it's obviously good to know (or at least have an informed guess) what age/sex of bird I'm looking at.

Even with poor eyesight, I think I can reliably identify a Sparrowhawk in it's first year - I cannot (and am unconvinced that anyone else can) reliably sex a juvenile, especially from a photograph. The only guide I find useful is the size of the feet/talons (bearing in mind all but the smallest females can subdue a Wood Pigeon is useful too, males struggle with even a sick/weak Collared Dove). I can reliably identify an adult male in clean bright plumage (as you know, older females can start to look a bit like males, so anything but perfect conditions can be more difficult for me). I can perhaps identify an adult female with more than a 60 percent chance of accuracy. A lot of the subtle feather differences noticeable to others I don't see, so any intermediate ages is only ever a guess by me.

I've found the nape pattern to be mostly unreliable, and I only ever put "possibly"/"probably"/"suggests" etc, if I point it out to others. Although there have been times when the pattern appeared to reinforce my first thought that a juvenile I was watching was male, but again, it's only a guess.
 

P.Sunesen

Well-known member
Hi Chris,

I just edited my post above slightly before I read your last contribution, and we agree completely as to the interesting/confusing variability of this common species.

Very instructive to see your many close up photos over the past years.

:t:
 

ChrisKten

It's true, I quite like Pigeons
I've seen that pic you linked to above before, Peter, but it's still fascinating. She's got the eye colour and rufous tones of a male - if I saw her on her own, the only clue it wasn't a male would be the talon and feet size. Although I wonder how many would be confident enough to ID her as an adult female ;)
 

KenM

Well-known member
I've seen that pic you linked to above before, Peter, but it's still fascinating. She's got the eye colour and rufous tones of a male - if I saw her on her own, the only clue it wasn't a male would be the talon and feet size. Although I wonder how many would be confident enough to ID her as an adult female ;)

Chris, like you I also see a lot of Sprawks albeit mine tend to be in flight and further away, have no problems with classic males (Spitfires) and large females. However my problem can be sexing them on size, because I've found that they ''often'' appear to overlap, and sometimes...I'm unable to gender reconcile! I've often wondered just what size variability there can be between the sexes with nisus.

As an example, a few years ago over the Leyton Dump/roundabout, I observed a male Peregrine being buzzed by a CC which appeared to be c10% bigger than (the Peregrine, which did look to my eye as being smaller before the encounter).

Cheers
 

P.Sunesen

Well-known member
Ken, there is hardly overlap in size between the sexes of Sparrow- and Goshawks.

They're mostly within a 5% variation, which isn't really notable in the field, and frankly neither in the hand.

If you scroll down to the bottom post on the Danish forum I link to, there's a link in blue letters, se linket her, which will lead you to another thread which will show a photo of the normal sizes of said two species (adult birds depicted).
A photo that will make a mockery of the oft heard phrase between - perhaps the not so experienced - birders:

"A LARGE female S.H. may be confused with a SMALL male G.H."

This almost makes as little sense as to claim that a large Crow may be quite similar to a small Raven in size.

https://www.fugleognatur.dk/forum/show_message.asp?page=1&MessageID=1960396&ForumID=1

Peter
 
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KenM

Well-known member
Ken, there isn't really overlap in size between the sexes of Sparrow- and Goshawks.

They're all pretty much the same "total length", but what can vary a lot is the weight. A dead, completely emaciated individual will appear noticeable more slim in the hand compared to a very fat and fit one, but hardly so in flight or sitting at a distance in the field.
On the contrary, dying birds are usually totally fluffed up, and will appear quite large in "body bulk".

https://www.fugleognatur.dk/forum/show_message.asp?page=1&MessageID=1960396&ForumID=1

Peter, I was talking about A.nisus-gender, not gentilis.

Cheers
 

ChrisKten

It's true, I quite like Pigeons
Chris, like you I also see a lot of Sprawks albeit mine tend to be in flight and further away, have no problems with classic males (Spitfires) and large females. However my problem can be sexing them on size, because I've found that they ''often'' appear to overlap, and sometimes...I'm unable to gender reconcile! I've often wondered just what size variability there can be between the sexes with nisus.

As an example, a few years ago over the Leyton Dump/roundabout, I observed a male Peregrine being buzzed by a CC which appeared to be c10% bigger than (the Peregrine, which did look to my eye as being smaller before the encounter).

Cheers

Peter has already replied, but just to reply to your question:

I can't give you any useful guide to the overlap between male and female, Ken - there really are some big males and small females.

This may sound fanciful, but I've seen adult males not much bigger than a Starling (I'll look through my pics if I get time) - the male's main advantage (apart from the obvious) over the Starling was his long legs. I've also seen males as big as Pigeons. OTOH, I've seen adult females that were no bigger than a Collared Dove.

As you can see from Peter's first link, even an adult female can be confusing. I'd say length is more reliable than bulk, as a bird that's just eaten looks much bigger, especially in flight or fluffed up digesting it's food.

So, I've not been of much help really ;)
 

KenM

Well-known member
Peter has already replied, but just to reply to your question:

I can't give you any useful guide to the overlap between male and female, Ken - there really are some big males and small females.

This may sound fanciful, but I've seen adult males not much bigger than a Starling (I'll look through my pics if I get time) - the male's main advantage (apart from the obvious) over the Starling was his long legs. I've also seen males as big as Pigeons. OTOH, I've seen adult females that were no bigger than a Collared Dove.

As you can see from Peter's first link, even an adult female can be confusing. I'd say length is more reliable than bulk, as a bird that's just eaten looks much bigger, especially in flight or fluffed up digesting it's food.

So, I've not been of much help really ;)

I think you’ve both made a contribution to their size variability. :t:

Cheers
 
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