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Monday, 20 June 2011

Little and Large Falcons

On my travels around London trying to keep up with the Peregrine population I get the chance to visit some unique sites, factories, high rise blocks, derelict brownfield sites along with working industrial sites. All are different and offer every kind of habitat going, disturbance on many is high, but on a number of these I have found that Peregrine Falcons and Kestrels do co exist and breed.


Male Kestrel

Male Peregrine
This year on the Peregrine sites that I monitor 4 pairs of Kestrel have bred on the same structure but at a lower level, both species are obviously aware of each other and there is some interaction between the 2 occasionally. It seems due to the abundance of prey in London, Kestrels are only occasionally targeted by Peregrines, the larger Falcon is basically lazy like most birds of prey, and seemingly always goes for the more abundant species.

In many cases this may be down to taste, feral pigeon may be more to there liking rather than Black Headed Gull for instance, the Gull is no doubt easier to take, so it could possibly be taste. Also the feral pigeon is just the right size to carry, I know that some Tiercels fly over a mile to a favoured hunting area, carrying the larger Gull back this far is hard work for the male, especially at dawn when there is no lift. I have recorded Kestrel as prey along with 2 male Sparrowhawks and know of other Kestrels taken as prey elsewhere. The smaller Kestrel will certainly go up and mob the Peregrine, I have seen this, some of this comes down to knowing when you can get away with it, and when not.



 Kestrel

Kestrel
On all of these sites where the 2 coincide I have noticed that the Kestrels give the Peregrines a wide berth at dawn onwards when they are 100% hunting, they fly extremely low to and from the nest site, and will not go up high. When the Peregrines have killed, fed and then layed up, the Kestrels will go up higher and even thermal. The Peregrines, although extremely aggressive and territorial do not perceive them as a threat to eggs/young unlike Carrion Crows, these are attacked with relish, laying up or not.

The Kestrels may just see the Peregrines as an occupational hazard, similar to Carrion Crows, they have a territory and a nest site, they are certainly not going to move site due to the presence of a higher authority, no matter how dangerous it could be.


Hopefully the Peregrines will keep to there normal prey
It is good to see the 2 species together, on one site both species have 3 juveniles apiece, that gives the possibility of 10 Falcons in the air, should be quite a sight,hopefully I may be able to get some photos.It will certainly be interesting to see how both sets of juveniles regard each other and to record any interaction between the two when they thermal.If the Kestrel juveniles are not deemed a threat, will they just be watched and not driven off by the adult Peregrines?



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