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Monday, 16 April 2012

An awkward scenario

Due to the numbers of peregrines in London, it is inevitable that they will find structures and buildings that are not suitable, either to hold territory on and ultimately attempt to breed on.
2 years ago I located an adult Tiercel on a structure, which due to its location and position always meant that, for breeding purposes, it was not ideal.
Early last year an immature Falcon turned up and the Tiercel was a happy boy, as expected due to her immaturity they did not try and breed but summered.Pre Christmas 2011, she now had her adult plumage, she disappeared for a while, some Falcons do this if there is no external threat from other peregrine pairs, food shortage has never been an issue in London. Late January she showed up again, the markings showed her to be the same Falcon, consequently nature took over and breeding was in the air with the pair copulating often.
Around March 28th she disappeared from view, consequent watching showed a couple of nest reliefs on the structure, by now I had decided exactly where she had made her scrape, it could not be seen but she emerged from the same position on 3 occasions with the Tiercel taking over incubation.
On April 8th after a series of heavy downpours, both the Tiercel and Falcon were permanently on show, obviously they had failed, the likely reasons being chilled eggs, lack of drainage on the level of the scrape or eggs simply rolling.
It is not uncommon for 1st time breeders to fail, in fact it is the norm but it does bring forth thoughts as to how to make them succeed.
Firstly every other tallish building in the vicinity is not ideal, either due to rooftops being used for Mobile Phone masts, they have to have 24/7 access, a nestbox and the Schedule 1 laws would stop any access. Others are just too low, additionally neither bird has never, as far as I am aware, used any of the surrounding buildings.
Secondly they never even looked at any other building/structure as an alternative; it was always going be ‘the structure’ where they are resident.
Working on the assumption that they will now hold territory every year and attempt to breed on this structure, it is likely that they will fail more often than not, this is usually the case in an urban environment unless they are assisted- Tray or Nestbox.Bearing in mind that the structure is not ideal for fledged juveniles and they may well ground, do you encourage them to successfully breed by placing a nestbox aloft knowing that it may lead to problems for the juveniles?
In my mind it has to be yes, obviously with the owner’s consent, they deserve the chance. Our unstable April and early May weather puts paid to many pairs on pylons, sometimes due to the fact that they don’t always use a stick nest and may well just lay on bare metal or some accumulated dirt. Consequently eggs become chilled/roll very easily, in short it is the exposed position that puts paid to them, hence the need for a nestbox.Such is the case with this structure.

A nestbox will solve the problem of a number of issues relating to their failure but successful breeding will also provide the challenge of grounded juveniles. In this case due to its very high urban location (people) and the dangers of, basically being run over if they ground, the only way I see forward is to publicise the site.
This will make the public aware of them and signs will have to be put in position during the breeding season, they are already known locally, this is the only way to safeguard them, as well as this local people can then get involved in their future.

It appears from the stats on the previous post  that  Falconers have been having a look at the hybrid, if anyone could shed any light on its identity it would be welcome.I have stated that it is an escaped Falconers bird as it fits no description, especially colour, of any Falcon that I know, if you know different I would welcome a comment.

Sunday, 8 April 2012

Peregrines - out and about

April 3rd
With so many Peregrines in London now I am spending more and more time trying to keep tabs on them, the best time has always been dawn, this is when you will likely get the information that you require to either confirm breeding or simply going through the motions of summering/ non breeding.

Such was the case this morning, up at just before 5.00 and in position by 5.45a.m,many of London’s Tiercels have a habit of slipping away in darkness to favoured areas where feral pigeons leave a roost, if you miss this you arrive on site and there is nothing. A Tiercel can be away from site sometimes for hours, once they have killed the Falcon will come out and feed, the Tiercel will then incubate. Once she has fed and filled her crop, she may just lay up and rest/or go straight back on the eggs, usually to the annoyance of the Tiercel, many are reluctant to hand over as they like to incubate. He may well hunt again in the afternoon after feeding off the remains of what the Falcon has left or he may retrieve stashed prey.
As it turned out, I sat there for 2 hours, I know they are there but it is likely he went in complete darkness and I didn’t see him go, additional to this I know of at least 3 pairs in London that are hunting at night, mainly in the winter months. If this had happened at this site he would have been present, either incubating or profile perching on ‘guard ‘duty.

Moving on to another site where they successfully bred in 2011 I was surprised to find a hybrid present, I knew he was in the area but it now appears that he/she has either paired with the Falcon/Tiercel or the pair from last year have moved site.
It appears from others that this bird is disrupting breeding to 2 pairs it seems ,I know over the last 2 weeks there has been some dogfights with a 3rd bird involved, presumably it could well be the hybrid.
I first saw it about 4 years ago, presumably it is the same bird, I know it has been doing the rounds of London as I keep hearing reports of a grey morph Gyr/Peregrine type here and there. Escaped Falconers birds are becoming a pain in the arse around London, the worry is that they will get into the peregrine bloodline.Dont get me wrong, it is a stunning looking bird but it is not good news if it disrupting breeding due to its size of an established pair.From here I moved onto another site.

Gyr/Peregrine hybrid?

By the time I got there the Tiercel was resting up on a Luffer Crane; this overlooks the incubating Falcon and is the male’s favourite perch.
On arrival a very amusing sight greeted me, the crane was working and the Tiercel was still in position perched at the very top!
Such is his bond and territorial tie to the nest site and the crane, (he could easily move to another lofted location nearby but further away) he stayed in position.
For the duration of the visit, about 40 minutes, he travelled north, south, east and west, up and down, only occasionally lifting a wing or 2. The cable wheel at the top was about 500mm from him and constantly revolving, by his actions he was obviously used to this.

Tiercel - not moving for no one

He was alert but it looked like he was not going to move for man or beast, the resilience of Peregrines never ceases to surprise me, I left there laughing as I saw him going on another circuit.