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Wednesday, 17 November 2010

An article on the small accipiter on St Mary's

You can also read and see more photos about this very interesting and educational bird on Martin Garner's excellent website, birding frontiers, 

On the 27th September, I had just left the airport and was driving down the start of the slope. To my right, out of nowhere, a Sparrowhawk alighted on a post about 2 meters in front of me. It was a juvenile bird, but it had buff underparts and brown upperparts with no bars but streaks! Even though there was nothing to compare it with, you could clearly see that it was smaller than your average male Sparrowhawk. It then shot off and chased an alba wagtail and landed in a nearby tree. Now, I've just observed a small juvenile male Sparrowhawk with streaked underparts and that's all I really got on it, because it all happened in a few seconds. I thought I would leave it and see if any other birders might get to see it better than me. I did tell a few of the local birders at the time, but that was it.
The following morning, I was up early and went looking for the small accipiter. I met Chris Jones, a visiting birder, at Higher Moors and when he had finished telling me what he had seen that morning, I asked him if he had seen a small Sparrowhawk? I was surprised when he said yes! He had observed it fly through half an hour ago with a female Sparrowhawk. He also saw it well on a rock at Peninnis Head, yesterday! I then asked if he saw very buff underparts and did it look small? He also told me that he had visited America. 'Are you thinking what I'm thinking?' and he said yes! Understandably, he didn't like to say to me or anyone else, that he thought it was showing some characteristic of Sharp-shinned Hawk. And that's the position I was put in.

 What do I do? Well, I could leave it and like yesterday, hope that someone else gets on to it or, I could alert birders of the presence of this small accipiter on St Mary's and then everyone will hopefully see it, what ever it is? It was decided to put the news out and it came out on Birdnet as, 'small accipiter showing some characteristics of a first winter male Sharp-shinned Hawk'. Why the hell the other pager service put it out as a 'small accipiter, probably an adult male Sparrowhawk', I will never know!? I thought that adult males are blue and juv/first winters are brown on the upperparts. Are they judging me? Did they see the bird? Is there something I've missed? In fact, it was almost three weeks later that the other pager service decided to put the news out in the same way as Birdnet. Birdnet put the news out, because it was an interesting bird that needed to be seen. While, the other pager completely blanked it and put the news out how they wanted to put it out! How can that be right? If these two pagers put out how they wanted to put the news out, without getting any information on the finding of the bird, then surely, a lot of people would be upset.

 Over the following month, I saw the bird very briefly about six times. It was also being seen by lots of visiting and local birders and they all said on how small it was. Those who saw the underparts, commented that it had streaks and couldn't believe it was a Sparrowhawk. However, it was never observed well enough to be
identified. Until that was when Jim Askin trapped it at Porth Hellick and even then, when it was in the hand, it was not positively identified!

3rd November

  Alan called me early this morning, 'Jim's caught a small Sparrowhawk with streaks'! I knew he had trapped my bird and thought at last the id will be clinched. However, as it was, it didn't turn out to be all that easy. I ran ahead to the ringing station at the back of the reeds at Porth Hellick and found Higgo was already there. Jackquelin took the accipiter out from the bag as Alan turned up, who I brought down in the taxi 10 minutes ago! Everyone was excited with what we were going to see, especially me.


wing length 191
tail 145
bill length 11, bill depth 8.5
tarsus 55.1
hind claw 11.8

“Stephen Menzie and Mark Grantham say that as a juvenile male, wing length shows it to be at the absolute bottom end for juvenile male Sparrowhawk but it’s still 8mm too long for even the largest Sharp-shinned Hawk. So the impression that it was a small bird was certainly correct.” Tom McKinney of Birdnet.
 On this juvenile Sharp-shinned Hawks underwing, you can see dark pencil line streaking and heart-shapes turning to bars where the axillaries feathers overlap the underwing coverts. Some of the heart-shapes foam bars. In comparison, the small accipter also shows heart-shapes and dark pencil line streaking in the same areas and less or no barring on the underwing coverts. Also, the feathers on this sharpie are pale with dark markings and on the small accipter, it's buff with dark markings.

 This juvenile male Sparrowhawk shows brown broad barring on the underparts, especially the flanks, and the undertail coverts are clean. Note that there are some brown broad streaking on the upperbreast only. If this extended all the way down the breast, this could be a good candidate for a possible Sharpie. If you look closely you can see one or two long heart-shapes on the underwing coverts, but no streaking. Otherwise, it's spotting with bars.

                Typical barring on the underwing and underparts of this juvenile female Sparrowhawk

     On this juvenile male Sparrowhawk, both the underwing coverts and underparts show very brown broad        strong barring. The streaking on the throat, is typical of Sparrowhawks.

On the small accipter, the underwing coverts show clearly heart-shapes and pencil line streaking. This points more to a Sharpie than a Sprawk which should show bars on the coverts, although, the latter can vary a lot. However, this is the only features on the bird that Sharpie shows and Sprawk does not. The barring, restricted to only the flanks, should emerge from the streaking on the upper-side of the breast instead of clear cut like the shot above and the underparts should be pale with buff streaking rather than dark streaking on buff underparts.

 A juvenile male Sharp-shinned Hawk. Again, note the heart-shapes, but the streaking is broader than that of the other Sharpie. The underwing must vary on most Sharpies, however, the heart-shapes are always present.

 To fill in some more of the identification ideas Martin Garner on his website asked Paul French to comment as he knew he has been looking at this subject for a while.

 “The Scilly hawk is actually quite an interesting individual. At first glance on the flight shots I was very happy it was small, but certainly a Sparrowhawk. On second glance, there are a couple of features that draw attention. The underparts do resemble Sharp-shinned, as it is distinctly streaked on the upper breast, and the pattern on the lower breast certainly recalls individual S-s Hawks in the NHM collection with a dark shaft widening out into a lozenge shape. However, the flank and thigh feathering betrays its identity as a Sparrowhawk. Here, broad bars spread out across the feather. Another factor is the rufous ground colour to the breast. Not that unusual in Sparrowhawk, but all of the Sharp-shinneds I’ve looked at were much paler, with a whitish ground colour. Also, the tail bars on Sharpie tend to be more prominent than Sprawk, and the back shot below (on blog) shows them to be quite dull.

N.B. when comparing biometrics of North American and Eurasian taxa, the wing length of American raptors is measured as unflattened chord, and British ringers generally use flattened chord.”

 As you can see in the left photo, the streaking continues all away from the lower throat to the center of the breast. From the upper-breast down, there are some dark isolated diamond and tear drop shapes and you can just see some dark barring on the right side flanks. The front of the lower throat shows dark pencil like streaking, broadening slightly, further down the breast. Sharpie can show these shapes, however the streaking is not right.

Dick Forsman commented on 'That this bird shows streaking to that of other Sparrowhawks he has observed and always the barring is restricted to the flanks and breast'.

                                                           Of the latter, you can make out that there is no barring on the
lower breast, which we also observed when in the hand. It was
white with only one or two dark spotting.

 “ … although not easy to see from any of my shots. This
bird definitely did not have bars down the central third of the undersides. The flanks and thighs were clearly barred but the breast and belly were not. I think we are all now happy that it wasn’t a Sharpie but it was certainly not your average male Sparrowhawk.”

This was a comment from my good friend, Martin Goodey,
who lives just down the road from me, on Martin Garner's website.

 Here in the left photo, you can see dark broader streaking on the upper-breast and instead of the steaking emerging into baring on the flanks, it's kind of all messy. What you can not see are the pencil line streaking on the throat. The undertail coverts are white with buff markings. The comments that came from the experts are, 'That Sharpies have white undertail coverts'. I thought Sparrowhawks also have white undertail coverts as well.

Also on this shot, the dark barring on the flanks are looking more like Sparrowhawk.

 In this shot, well it might as well be a Sparrowhawk.

 All these streaks, barings, markings all point to Sparrowhawk, except for the underwing coverts showing streaks and heart-shapes rather than barring of a Sparrowhawk, all I can say is, thank god Jim caught this one! Jim told me that when he pulled it out of the net, although a small bird, it felt like a female! Attentions, from some other birders, have switched towards a possible female Sharpie, as the measurements are spot on! Jim also said that he couldn't really put a name to this accipter and he had to put a name of a species in his book, Sparrowhawk. I think there's no doubt that this is a very unusual Sparrowhawk and we have got a lot to learn from it.

 All photos were taken by Martin Goody.

Footage of the small accipiter being ringed at Porth Hellick

A shot of the small accipter taken by Mark Yates. Note, what looks like broad buff barring on the flanks and buff streaking on the underparts, Also, it gives the impression of being smaller and shorter tailed than that of a Sparrowhawk. In the field, everyone commented on how small it was and it flew more like a Merlin and that's the impression I got when ever I saw the bird.

 Here is a shot taken of a Sparrowhawk at Flamborough by Brett Richards, showing what looks like streaks and no bars. Brett told me 'In the field the bird seemed to show indistinct barring on the lower breast, not at all apparent in the photo, where the streaking appears to extend all the way down.'

Below are some shots showing variations in the underparts on three different juvenile Sparrowhawks. Note that they are all barred.

 Overall I have no experience with Sharp-shinned Hawk and thought this was a very interesting bird that everyone should see as it did show some characters of a Sharp-shinned Hawk and put the news out. Even in the hand it was not identified. In the end, it's a very interesting and unusual Sparrowhawk and looks like it might winter here.

 I would like to thank everyone who took part in helping me out with this Sparrowhawk.

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