Granville Pictor, RSPB Salisbury Peregrine Volunteer, gives us the low-down on the dramatic Salisbury Cathedral peregrine's battle for the skies - as featured on BBC Springwatch.

Regular readers of our 2017 blog, and indeed viewers of last year's Springwatch, will be well aware of the exciting (maybe too exciting) events at Salisbury Cathedral last year. First there was disappointment that only one out of the clutch of five eggs actually hatched. There was however a happy ending when a chick rescued from a nest in Shropshire, where both parents had been poisoned, was successfully fostered into the Salisbury nest and both of the chicks subsequently fledged .

   

Photo 1 left: Single hatched Salisbury peregrine chick 2017      

Photo 2 right: Orphaned Shropshire chick successfully adopted by Salisbury peregrines, 2017

Early 2018 satellite data from the transmitter on our resident female Sally (colour ringed SY) revealed she was ‘in residence’; indeed she has not strayed more than about 8 miles from the cathedral since she was satellite tagged in May 2017. A male was also seen with her around the cathedral so it seemed all was well and we could settle down to a trouble free breeding season putting the ups and downs of 2017 behind us...how wrong can you be!

At the end of March a local observer took a series of photographs of such good quality that it was possible to establish that the male bird was not the male from 2017 (‘Sebastion’ colour ringed SB), but an un-ringed adult. This of itself was not a great surprise as, whilst adults are generally site faithful, inevitably birds do die and are replaced, or other birds with no territory try to ‘muscle in’ and take over the territory from the resident bird. Quite what happened to Sebastion we will probably never know unless of course he is photographed and his ring read at another site. The cathedral is a towering pinnacle of limestone in an otherwise fairly flat agricultural landscape and is visible from many miles away. It is therefore perhaps not surprising that it probably acts as a magnet in attracting in other un-mated peregrines looking for a territory. It is only of course the advent of colour ringing and video technology that has enabled us to identify these changes of occupancy at the nest.

Photo 3: Adult peregrine courtesy of Salisbury Cathedral

The change in the adult male was not a cause of concern, and he and Sally seemed settled and were seen to engage in courtship behaviour. Very shortly afterwards however there were reports of three birds at the site, and in early April when the video camera was switched on, there was footage of the new male and a new un-ringed female on the nestbox engaged in courtship activity. Data from Sally’s transmitter revealed that she had not been chased off by the new female, so we anxiously waited to see who would become the dominant female and actually lay a clutch of eggs. We were at this stage a little concerned that there were no eggs in the box in early April as other urban pairs we knew of had full clutches by then; perhaps it was just the cold weather delaying things; who knows perhaps both females might try to lay eggs in the box..

Alas, it was not to be and on the evening of 26 April things really did come to a head. Captured on video is a battle lasting the best part of an hour between the two females, the fight taking place on the walkway adjacent to the nest box. Both birds can be seen with talons locked, pecking at each other and rolling around on the walkway in a really viscous fight with feathers flying in all directions. Sally appears to have been the victor as she is seen sitting on the edge of the nest box the next morning and hopes were then high that having seemingly vanquished the new female, she and the male would now settle down and lay an albeit late clutch of eggs. Alas it was not to be, and as I type this note in late May, there are no eggs laid and the same three birds are still present at the site. Sadly it seems that there will be no breeding attempt at the site this year.

      

  

Photo 4 top left: Sally on the right

Photo 5, top right: The intruder has Sally on her back.

Photo 6, bottom left: Sally pins the intruder down.

Photo 7, bottom right: Talon to talon combat near the nest box - Sally pins intruder down

(Photos taken from the Salisbury Cathedral webcam and RSPB South Wiltshire Facebook Page)

Whilst the failure to breed this year is disappointing, the video footage does reveal fascinating insights into the territorial behavior of peregrines. The results of the very recently published 2014 British Trust for Ornithology National Peregrine Survey reveals that the species is thriving in southern England, with a big increase in numbers breeding with success on man made structures like the cathedral. With increasing numbers of adult birds joining the population and seeking territories, it is perhaps not surprising that pressure to breed on a relatively limited number of nest sites is increasing and territorial disputes such as seen this year at Salisbury may become more common place…but not again at Salisbury please!

Photo 8: Sally (corner of geolocator on her back just showing) guarded her nest overnight. Still there at 08.00 on 24 April.

For more information about the Salisbury Cathedral peregrines and to follow their YouTube Channel, click here.

Anonymous