Peregrine Watch Report 2002 - Plymbridge Woods

Introduction   Chronology   Breakdown of Prey   Visitor Numbers   Finance   Volunteer Participation   Legal Status  Species

Introduction

For many years, Cann Quarry, an abandoned slate quarry situated within the boundaries of the National Trust property at Plymbridge Woods on the outskirts of Plymouth, has been the nesting site for Peregrine Falcons (Falco peregrinus).

In 1999 a pigeon attached to fishing line was discovered on the quarry face; believed to be an attempt to poison the falcons. The following year a similar and ultimately successful attempt was made using pigeons baited again with an agricultural pesticide resulting in the deaths of the adult female (falcon) and two of the young (eyasses). The other eyass also disappeared from the eyrie but the carcass was not recovered and there is no record of what happened to the adult male (tiercel).

These events and the ensuing media interest led to the National Trust and some local residents to mount a watch on the eyrie, during the breeding season. The watch was backed up by covert surveillance cameras on loan from the RSPB. The RSPB regarded this site as high risk and were keen to obtain a conviction following a spate of poisonings in the Southwest of England and South Wales, two of the most important areas for peregrines in Southern Britain. Security around the eyrie was also increased by the placement of barbed wire and signs along the quarry top making access more difficult. This proved to be a success and three young Peregrines were successfully reared during 2001.

Following meetings between the National Trust warden, Gus Fergusson, the RSPB and the watch volunteers at the end of the season, it was decided that a full time volunteer was required to co-ordinate the watch and man a viewing station for the general public. To achieve this an advertisement was placed in CJS looking for candidates and in March 2002 Reg Fairbairn was offered the post.

After consultation between the relevant parties it was decided that the viewing platform should be based on the Cann Viaduct. This viewing area would be manned on Saturdays and Sundays, 10.00 am -4.00 pm (weather permitting).

To increase security a caravan, loaned by Plymouth Caravan Centre, was situated adjacent to the top of the quarry so that a 24-hour presence could be maintained on site. After site visits by both the police (Police Wildlife Liaison Officer, Dave Weldon) and the RSPB Species Protection Officer (Chris Townsend) to inspect the security arrangements, the watch commenced on 18th March 2002.

The viewing facility was enhanced by sponsorship from the London Camera Exchange (LCE) facilitated by two telescopes donated by OpticronTM and VikingTM Optical. A further telescope was supplied by the RSPB and was manufactured by SwarovskiTM Optical. Furthermore RSPB funded the production of 50 colour posters, 5000 colour flyers and 2000 leaflets about the peregrines presence in Plymbridge. 3000 of the flyers were distributed around the area to public places, such as schools and libraries. These were linked to their nationwide "Aren't Birds Brilliant" campaign. Press coverage was excellent with features in most of the local newspapers as well as photographs in The Daily telegraph. The post of the peregrine warden was initially set up as a voluntary position but with subsequent funding from Plymouth City Council was ultimately converted to a paid seasonal National Trust contract.

Chronology of Main Events

The first sighting of the Peregrines during 2002 came early in February when the Falcon was spotted on the quarry face. She was seen alone there on two occasions prior to 14th February when the male was also spotted in the area, as peregrines mate and hold territories for life it is assumed that this is the same breeding pair from the previous year.

By the start of March the birds were prospecting old Raven nests as possible sites for this years eyrie and on the 14th March they were observed displaying courtship behavior. Two days later a third peregrine was in the area of the quarry but it was chased of by the tiercel.

On 18th March the watch was officially started, as the falcon appeared to be laying. She had decided to use an old raven nest situated 2/3 of the way up the cliff-face on the right hand side of the quarry. This site had been used by peregrines previously in the year 2000 when the birds were killed.

10 days later, 28th March, the falcon settled on the eyrie and the tiercel started passing food without mating, suggesting that the full clutch had been laid (4 eggs) and that incubation had started. For the next 4 weeks the birds shared incubating duties with the falcon doing most of the sitting. In general she was only off the nest for short periods of time to hunt and clean herself before relieving the tiercel. During this period a dead Buzzard (Buteo buteo) was reported to the watch but the carcass had been removed before the cause of death could be ascertained. This continued until 25th April, when the tiercel was observed removing something small and pink from the nest. It is thought that this was either a stillborn eyass or perhaps an infertile egg. Unfortunately magpies picked the object up before it could be examined. Both adults continued incubation until 29th April when the falcon became noticeably restless in the eyrie signifying that the eggs were hatching. This was confirmed on 30th April when the falcon was observed placing small pieces of meat into the eyrie, and again on 2nd May when two downy heads were seen in the eyrie. On the same day there was a rockfall directly above the eyrie but fortunately there was no damage to the birds as it was protected from above by an overhanging piece of cliff. The falcon was doing almost all of the sitting at this time, leaving only to clean, whilst the tiercel was catching all the prey (rapt), bringing most of it back and giving it to the falcon. There were also visits by the media during this week to publicize the hatching.

After a tip-off from the RSPB on 6th May suggesting that someone had been paid to destroy the birds, a full 24-hour watch was initiated. A day later the third and final eyass had become large enough to be seen from the viaduct. The falcon started hunting again on 11th May, leaving the nest unprotected for brief intervals. A magpie took advantage of this and was seen to pick one of the eyasses out of the eerie; fortunately the tierce was nearby and scared the magpie away before any damage was done. By 21st May the eyasses had started to show plumage and by 31st May it covered approximately 2/3 of the young birds.

An unforeseen event took place on 1st June when representatives of the racing pigeon fraternity held a protest against the peregrines. This demonstration was conducted peacefully and after making their point they left. It should be noted that all the members of staff gave up some of their own time to attend this incident. From 4th June the young birds appeared fully feathered in adolescent plumage and entered the "rock-hopping" stage of development. This continued for eight days till, on 12th June, both young males fledged though the female didn't fly till 16th June, possibly due to her greater size.

On 20th June, the adults commenced training the fledglings to hunt by passing food in mid-air, dropping some prey to encourage stooping in the young. Much of the prey is wasted at this stage as the young drop, or fail to catch, many of the food items. Gradually over the next week the young became more proficient at catching dropped food and on 28th June the adults started taking the adolescents out hunting. Also on the 28th a young male was asleep on the top left side of the quarry when a fox attempted to catch him but failed. By 7th July when the London Camera Exchange held an open day on the viaduct, the young were proficient fliers and considered safe as they were taking part in the hunts. It was decided to wind down the official watch though some volunteers agreed to visit the site infrequently to make sure no late attempts at the birds were made.

On 9th July another Buzzard was found adjacent to the river Plym; this bird was in poor condition and was taken to the vet where it was found to have a fractured wing caused by shooting.

Breakdown of prey

Prey records for the season are incomplete and therefore the following charts and conclusions can only be taken as an approximate guide to low catch estimates.
Fig.1.1

The chart above (fig 1.1) shows the total number of prey recorded broken down by species. It shows that a total of 48 pigeons were positively identified as prey items (N.B. Pigeon records incorporate all sub-species such as Feral pigeon, rock dove etc. and also no differentiation is
made between wild pigeon or captive birds, for example Racing Pigeon). The falcon caught the majority of these pigeons.

The most common prey for the tiercel was starling (Sturnus vulgaris) and the records show that 36 were positively identified. 12 Blackbirds (Turdus merula) were recorded and again the tiercel caught the majority of these as is true of the 4 Thrushes (Turdus philomelos) and 2 Grey wagtails (Motacilla cinerea) recorded.

The last category is prey that was unidentified and almost certainly contains some of the species detailed above together with numbers of other small birds. A total of 31 unidentified prey items were recorded giving a total of 133 recorded kills.

If we assume that each adult eats 1 bird per day and that each eyass consumes 1/3 of a kill/day in the first week of development, 2/3 in the second and a whole bird (depending on size of prey) thereafter then we attain a figure of 416 prey items over the breeding season (18/3/02-10/7/02) then we have identified roughly 25% of the rapt taken. N.B. This figure (416) is a low estimate as many kills were lost during the period when prey was being passed in mid-air.

Fig.1.2

Figure 1.2 (above) breaks the numbers of recorded prey down into percentages. When considered and extrapolated using the season total above (416) this gives the following totals for the watch duration (18/3/02-10/7/02):

These figures should again be regarded as low estimates as we started with a low estimate for the season and there are also 93 unidentified prey items to consider.

Visitor Numbers
Figure 2.1 (below) details visitor numbers for Saturday and Sunday of each week.

A total of 2609 members of the public stopped to view the peregrines at weekends over the duration of the watch. The maximum number of visitors was on 12th May when 160 people showed interest in the birds. The lowest attendance was 34 and was recorded on one of the many wet days (low values on the chart). 120 visitors were attracted to the area on 7th July when the LCE held their open day. The average daily number of visitors at weekends was 93. It is hoped that next years numbers will be even better as there was unseasonably wet weather during May and June.

Figure 2.2 shows weekday visitor numbers over the season. It can be seen from the graph that visitor numbers during the week were lower and fluctuated less than those at the weekend. It should also be noted that weather conditions had less of an impact on weekday numbers, this is mainly due to the large number of people who use the woods to exercise their dogs.

The busiest weekday was bank holiday Monday 3rd June when 113 visitors used the viewing facility, these were mainly families as there is something of a tradition in Plymouth for folk to visit Plymbridge during this holiday. The average number of visitors was 32 and the total for the season was 2080.

Fig.2.2

The total for the season as a whole was 4689, with an average of 50 visitors per day. As previously stated the maximum was 160 and the minimum was 22. These figures are records of visitors to the area who used the viewing facility and do not represent the total number of people who visit Plymbridge Woods during the summer. NB. The season total includes many folk who visited the site on more than one occasion and they do not imply that 4689 different individuals used the facilities.

Finance
Over £130 was donated to the watch via the collection box situated at the viewing point.

The costs of the project were mainly as follows: telephones £110, printing (excluding RSPB contribution) £40, volunteers sundry expenses (2 BBQ's) £150, volunteers' travel expenses £250, peregrine warden's wet weather clothing £220, miscellaneous (including gas and items for caravan) £120, total approximately £890. These figures do not include any remuneration for the peregrine warden nor the costs of the NT vehicle or staff time.

Volunteer participation
Fig.3

A total of 47 volunteers, including National Trust personnel, took part in this years watch.
Figure 3 shows the weekly amount of time covered by volunteers. The chart shows that over time, as more people became involved, volunteers covered more hours. Less than 10 individuals were involved at the start of the watch and only 46 hours were covered. This increased to approximately 80 hours by the time hatching occurred. Following visits by the media to record this event many more volunteers came forward and therefore hourly coverage increased, to 120h/w.
Weekly hours remained reasonably stable and peaked as the birds were due to fledge (at 133 hours/week). After fledging numbers remained almost constant until the watch was scaled down, week ending 14/7/02.

Volunteers, averaging 101h/w covered a total of 1408 hours. This total does not reflect the 'man hours' which is considerably more, as most volunteers brought a friend or partner.

Legal Status of Peregrines

Peregrine Falcons are amber listed on the endangered species list. This means that although the species is not in imminent danger of extinction, numbers are still low enough to merit attention.
This species is also protected under Schedule 1 of the Wildlife and Countryside Act (1984) and the more recent Countryside and Right of Way Act (2000). These acts allow for fines of up to £5000 and/or imprisonment for offences against these birds.

Acknowledgments

We would like to thank everyone who contributed to a very successful season, including:

RSPB, London Camera Exchange, Plymouth City Council, Plymouth Caravan Centre, Viking Optical, Opticron, BBC Southwest, Carlton TV, BBC Radio Devon, The Daily Telegraph, Devon & Cornwall Police, The Western Morning News, Sustrans, the Forestry Commission, the general public for their interest and support and last and most important thanks to the many volunteers who gave up their time to make this a success.

Reg Fairbairn
Peregrine Warden, National Trust, Southwest Dartmoor
Appendice 1

Other species recorded
The following species were all recorded on at least one occasion within Plymbridge Woods and many of them were seen on a daily basis.

References and further reading.

The Peregrine Falcon, Derek Ratcliffe. Birds by Characteristic , Rob Hume