Nordic jackdaw, Norfolk (1 Viewer)

[ben_lewis]

I saw a flock of jackdaws from the car going through Heacham earlier, stopped to have a look and this was in with them, pretty sure its not a standard jackdaw, I know the Jackdaw subspecies' are a nightmare but any ideas?

Ben

 

[Motmot]

Check this out:

http://www.xs4all.nl/~calidris/monedula.htm

 

[ben_lewis]

Thanks Walt, I'll have to read that a little later but looks like it could really help with the id.

Cheers

 

[Motmot]

Thanks Walt, I'll have to read that a little later but looks like it could really help with the id.

Cheers

I'm no Walt...:-O.
I should have signed my post
Cheers,
Eduardo

 

[ben_lewis]

LOL, Maybe I should have read the name!

Cheers Eduardo

 

[eagle33]

The exact origin is hard to tell but the pale spot in the foreneck of most birds followed by a less marked silvery collar points to Eastern Europe, perhaps Poland

 

[Hotspur]

due to the dark scaps plus the neck collar I guess your bird is an intergrade monedula/spermologus from somewhere in the central european hybrid zone (which runs from eastern netherlands- to switzerland across germany).

 

[Alan Tilmouth]

due to the dark scaps plus the neck collar I guess your bird is an intergrade monedula/spermologus from somewhere in the central european hybrid zone (which runs from eastern netherlands- to switzerland across germany).

Whilst I agree this bird looks like an intergrade monedula/spermologus why would it not be a UK bred intergrade or simply a resident bird with some monedula genes?

 

[ben_lewis]

Whilst I agree this bird looks like an intergrade monedula/spermologus why would it not be a UK bred intergrade or simply a resident bird with some monedula genes?

Good point, however I would have thought a jackdaw looking as distinctive as this if resident would be reported a lot more given its N. norfolk location, or whenever this bird was seen in the uk id have thought it would be seen as 'different' and hopefully reported.

I'm going to try and get a better photo of the bird today- was taken in the pouring rain yesterday, im particularly interested to see the breast of the bird now that I know what to look for to id the different races.

Cheers

 

[Hotspur]

Whilst I agree this bird looks like an intergrade monedula/spermologus why would it not be a UK bred intergrade or simply a resident bird with some monedula genes?

Because the hybrid zone is further east than the UK. Thats not to say that monedula genes dont reach these shores in terms of breeding but the picture was taken in winter and Jackdaws are migrants so it is more likely a wintering bird.

 

[Alan Tilmouth]

Because the hybrid zone is further east than the UK. Thats not to say that monedula genes dont reach these shores in terms of breeding but the picture was taken in winter and Jackdaws are migrants so it is more likely a wintering bird.

Sorry James, the picture was taken in Spring (albeit just)

Rudy Offerein's paper linked to earlier in the post states "Voous (1950) and Voipio (1969) consider nominate monedula to be the westernmost representative of the westerly expansion of the soemmerringii-branch. In short, this would mean that nominate monedula is basically the link between the two best most easily separable subspecies, being namely soemmerringii and spermologus."

and "Mixed breeding of spermologus and monedula has been reported on several occasions in the Netherlands"

I guess what i'm suggesting is that if all spermologus are descended from monedula and mixed breeding occurs just a couple of hundred miles east then perhaps it has ocurred here in the past and that some of the birds we see with the pale collar characteristic are carrying that monedula gene but are not necessarily migrants. I have stated elsewhere that I feel wary of the fact that many of the UK records of Nordic are at a time (Mar-April) when wear can show a pale collar on spermologus, although from the pictures this bird would appear not to be simply a worn spermologus.

 

[Hotspur]

I guess what i'm suggesting is that if all spermologus are descended from monedula...

The problem with this is that spermologus are not stated to be descended from monedula - but monedula is the westward expansion of soemeringii linking with spermologus. The origins of the subspecies aren't discussed. Thats not to say that you are wrong - spermologus may well descend from monedula but the nominate wasnt the race the others were descended from, merely the first to be named. In my head im seeing this as similar to Carrion/Hooded Crow with a stable hybrid zone but with greater gene flow and a lack of habitat differentiation (wonder if anyone wants to do an assortive mating study - tee hee). Having said this Its likely that if placing the Jackdaws in their own genera with 2 species, Coleus, is correct (as i suspect it is) then an eastern palarctic or easterly western palearctic origin is most likely. Ive had a little dig (but i dont have BWP so cant forward info from that) and i cant find anything on the geographic origin of Eurasian Jackdaws.