Spain:Do Lesser Kestrel and Common Kestrel interbreed ? (1 Viewer)

[Stephen Fletcher]

I was photographing a newly arrived colony of Lesser Kestrel this afternoon, approx 10 pairs, all living happily together, and interacting, circling around, landing together and calling. When i got home and looked at the images, this female stood out amongst the others. It has a strangely coloured head, no longer centre tail feathers, a darker breast hue, and dark toenails. It doesn't look like a Common Kestrel, but also appear not to be a Lesser. 1st year female perhaps ? Any ideas anyone ?

 

[John Cantelo]

I'm not terribly expert at judging wing formulae but LK should have P7 much shorter than P10 whereas in Kestrel they are of equal length. In this photo P10 & P7 seem to be equal in length which suggests Common Kestrel......

 

[Black Wheatear]

Hi Stephen,

I've not heard of any confirmed cases of LK breeding with CK, but you cannot rule out the possibility. I would have to agree with the comment made by John on the wing formula, and going along with other features mentioned by you, it appears more likely the photo shows Common Kestrel. Whilst watching migrating LKs in Morocco last Spring, we also witnessed a male Common Kestrel, which we assumed was resident, mixing happily with these migrants.

Peter

 

[CAU]

I would disagree on the wing formula, to me it looks better for Lesser Kestrel (longer P10 than P7 and longer P9 than P8).
Lesser Kestrel:
http://www.tarsiger.com/images/pepe/falnau_n_esp_260407_DSC_0767testi.jpg
Kestrel:
http://www.tarsiger.com/images/Jniemi/faltin025copy72.jpg

Also the head pattern looks better for LK (no dark line behind the eye). Lesser Kestrels and Kestrels are really difficult to age from below in spring, in this case perhaps the strongly patterned underwing coverts point towards a 2cy bird.

Lesser Kestrels may often show proportionally longer central tail feathers (as also Common Kestrels...), but this is usually because the white tips of the other rectrices wear faster than the dark tips of the central pair (2cy birds also often moult the central pair in winter, which adds to the phenomenon). When all the feathers are equally fresh, they also often look equally long.

I can't really comment on the probability of a hybrid (in Finland a 2cy male LK spent once a summer with a female Common Kestrel, which also was observed begging for food from the male, but no certain nesting was recorded), but I'd think that it's more likely that the bird is just a slightly different looking Lesser Kestrel.

 

[Stephen Fletcher]

I agree entirely that the 2 species will happily migrate, but these were all interacting as if sharing traits and jizz, landing close together, fighting off rivals, same calls etc. I did not see this particular bird doing anything different at the time i was there, and as i mentioned, i didnt even notice it among the other 19 there, it was only when home that i saw the differences.

Thanks for the help guys, ill go and look out specifically next time, and see if i can pick it up easily or not.

 

[Stephen Fletcher]

Thanks CAU, very helpful. Fascinating stuff.

 

[john-henry]

Certainly appears to be a Common Kestrel (Falco Tinnunculus) but this is not necessarily an indication they might interbreed. There is at least one colony of Common Kestrels in Spain (in the Donana area) showing if conditions allow, for whatever reasons, colonies of these can exist.

If possible Stephen it would be of great interest if you could keep your eye on this colony and see what happens during the breeding season. It may just be a case of a Kestrel moving with a colony of Lesser Kestrels and then moving on again.

 

[Stephen Fletcher]

ALL the others were DEFINITELY Lessers. Ill certainly monitor them closely, they are very close to my house so no problem.

 

[JANJ]

CAU is right, wing formula is perfectly shown here (not always so obvious in certain images - and of course in moulting individuals).
Also note broader dark-tipped primaries.

Some good Lesser's here:

http://www.javiermilla.es/primillas/index.htm

JanJ

 

[bitterntwisted]

Is the claw colour not diagnostic? Or could it just be the angle and light that make the subject bird's claws look dark?

Graham

 

[Black Wheatear]

Is the claw colour not diagnostic? Or could it just be the angle and light that make the subject bird's claws look dark?

Graham

Quite right Graham. Also a few decent photos on this thread of LK in flight showing wing formula. http://www.andalusiabirdsociety.org/forum/index.php?topic=31.0

 

[JANJ]

I also noted the seemingly dark claws, which is not a Lesser Kestrel feature indeed.
So I wonder - with all the other good for Lesser features, such as wing formula - p10 longerthan p7, sometimes more obvious than on this individual, more or less equal in Common. Also p9 & 8 usualy are equally long in Common, p9 slightly longer than p8 in Lesser. Pale, almost unbarred primary bases and broad dark-tipped primaries looks good Lesser.

JanJ

 

[John Cantelo]

Curious, but I've just taken a ruler to those primaries an I'm damned if I can make P10 longer than P7! They look exactly the same length, but as I said I'd never claim to be an expert on judging wing formulae!

However, like JANJ I thought the detailed pattern of the primaries looked better for LK. With regard to the claws, to me if you look very carefully at the base of some of the claws, they do indeed look pale. I've found it not unusual to see LKs which appear to have darkened tips to their claws presumably due to a dirt or mud being caked on them,

 

[Stephen Fletcher]

In fairness, i dont think the original photo is a good example for measuring primaries as the perspective is altered by the wing angle. I managed to root through the recycle bin and find this one from a few frames earlier. It clearly shows 10 larger than 7, and 9 & 8 equal. Interestingly too, its shows the claws pale !!!! I am perfectly happy it is a Lesser Kestrel. It does show how even a true likeness photo can be fooled into thinking there is something there that isnt. Thanks for all the invaluable help though guys, and gals.

Sorry for any consternation caused, next time ill do a little more research before asking.

 

[John Cantelo]

I'm not trying to cast doubt on the ID of this bird as LK since that's it seemed to be to me before the apprent wing formula unnerved me. Even with a ruler held to the screen this did not seem to fit the P7/P10 formula for LK (although in the later photo it was clearly a better fit for this species). What genuinely interests me is how some can look at the original photo and see (correctly) the relative lengths of the wings so differently than I can manage? It would seem that the proportions were distorted in this photo but how do some people recognise this in such a 'one off shot'? Perhaps it merely reflects the fact that I'm not a ringer and don't handle birds,

 

[username]

Seems to me this whole single 'photo id' thing is almost a different 'art-form' as oppose to identifying birds in the field! Some Q n A 'single shots' are notorious i find....in some cases i would never be 'that' confident! I do admire, however, the very skilled contributors on this forum.....i learn something new everyday it seems!

Camera never lies?!!......hhhmmmm......

ps..in the field i have witnessed a terns bill 'turn' from red to yellow as it flew by [depending on the angle of light] etc....quite worrying sometimes what 'angles' can do!