March 5th and 6th and territorial squabbles

An excellent weekend relating to the site visits of February 23rd, both nest boxes have been accepted with both Tiercel and Falcon encouragingly occupying there respective boxes. The early signs are looking good, hopefully in 2011 we will have a good breeding year.

The potential in London is enormous if they all succeed , but due to a number of factors, they are not reaching there full capabilities, unstable weather, egg rolling, poor nest site selection and in some recent cases, infertility. If they can get past all this, the success rate would be far higher, and until recently, It did not occur to me that there could be other factors in London that could effect them to the extent that it would interrupt breeding.

Tiercel

I recently covered a pair in London, every day for 5 days, 2 days, then a gap and then 3 days in a row whilst activities took place.

In this period of time, the resident pair were kept extremely busy defending there site and territory as not only singles tested them but also another pair on the edge of there territory. For the full 5 days, they were challenged no less than 4 times a day, on one day, they received 6 visits by other singles/Immatures and pairs, I am presuming it is just one pair. Saying that, on at least 5 occasions they came in so high they could have come from anywhere in London, they were dots, the only reason I saw them was due to the reaction of the resident pair.

Tiercel

I know from visits in the breeding season of 2010 that, occasionally when I was monitoring them, they received challenges from other Peregrines, this at the time I thought was only sporadic, I am now thinking that this may be the norm in London. This may well be attributed to the high density of Peregrines in London, checking out your neighbour, so to speak, but it could well be singles/pairs looking to take over a site and testing the strength of a pairing.

Intruding pair

On this particular site the pair disappeared every day for an hour or so, without fail, even in not ideal weather, it was not to hunt as they had already killed and fed, so I wondered are they doing the same and checking out the opposition, it appears from the 5 days that territorial boundaries were not observed by other Peregrines.

Intruding immature female being driven off

One other reason may be that this site is a ‘ prime site ‘ and as such, is in demand and will be constantly challenged, whether it be from neighbouring pairs or migrant/singles looking for a ‘core’ structure or territory of there own.