Holyrood Park Meadow Pipits and Skylarks 2011 – Graham Checkley – 14/05/2012
Introduction
The purpose of this document is to provide an account of the status of the Meadow Pipit (Anthus pratensis) and the Skylark (Alauda arvensis) within Holyrood Park, Edinburgh, during 2011. As such it provides information on the distribution, occupancy and breeding success of these species based on the methods for Skylark documented in ‘Bird Monitoring Methods’ (Gilbert, Gibbons and Evans, 1998), but with the addition of casual records acquired from Historic Scotland Ranger Service (HSRS) patrols. Full length electronic versions of this document including all appendixes, maps, tables and references may be obtained from the author via his profile.
Background
Holyrood Park is 263 hectares in extent, and is unique within the City of Edinburgh as an example of lowland, unimproved grassland, a habitat type which is rare and declining across the UK (Edinburgh Biodiversity Partnership (EBP), 2010). It is designated as a Scheduled Ancient Monument and as a Site of Special Scientific Interest (SSSI), and is managed by Historic Scotland on behalf of the Scottish Government. The management of the grassland of Holyrood Park has been identified as a priority habitat action within the Edinburgh Biodiversity Action Plan (EBAP). HSRS are currently working with Scottish Natural Heritage (SNH) to carry out trials of 5 management regimes on the unimproved grasslands at Holyrood Park, “with the aim of bringing them into favourable condition” (EBP, 2010).
This grassland provides a city-centre habitat for ground nesting birds such as the Meadow Pipit and the Skylark, both defined by the British Trust for Ornithology (BTO) as “species of conservation concern within the UK”. The Meadow Pipit has been assigned an amber conservation status within the UK due to its recent breeding population decline (BTO, 2010). It is also a notable local species under the EBAP (EBP, 2010). The Skylark, however, has been assigned a red conservation status within the UK due to its continued breeding population decline since 1969 (BTO, 2010). It is also a target species within the UK Biodiversity Action Plan (BTO, 2010) and a notable species under the EBAP (EBP, 2010).
Within Holyrood Park itself the 1992 Scottish Wildlife Trust (SWT) breeding bird census concluded that there were between 10-13 Skylark territories, and 25-30 Meadow Pipit territories (SWT, 1993). Skylark were noted as being associated with the higher acidic grassland, whereas the Meadow Pipits were considered to occur in a wider variety of habitats including neutral grassland (SWT, 1993).
The Holyrood Park 2001 Linnet, Skylark and Yellowhammer survey identified Skylark territorial or other breeding behaviour at 16 locations within the Park, mainly amongst the grassy areas of Whinny Hill and on the slopes between Salisbury Crags and Hunter’s Bog (Swinney and Pearson, 2001).
An initial examination of HSRS wildlife log by the author suggested some decline in the distribution of Skylark within the Park during the last ten years, with less singing birds being noted and the effective abandonment of the Dunsapie Crag area by this species (HSRS, 2011, unpublished). It has not proven possible to reach any conclusions regarding Meadow Pipit numbers. As 10 years had passed since the last Skylark survey and 19 years for Meadow Pipits, the author, following discussions with HSRS, decided to carry out a distribution, occupancy and breeding success survey of these species in 2011.
Aims
To determine the distribution, occupancy and breeding success of Meadow Pipit and Skylark within Holyrood Park during the summer 2011 season.
To provide a methodology that can be used to carry out subsequent surveys.
Objectives
To undertake a survey of the Meadow Pipit and Skylark breeding season populations within Holyrood Park.
To use any records for these species from HSRS patrols in order to obtain additional information on distribution and breeding behaviour.
Methodology
Introduction
The approach adopted for both species is based on the methods for Skylark documented in ‘Bird Monitoring Methods’ (Gilbert, Gibbons and Evans, 1998), but with the addition of site specific transect routes and the collection of additional behavioural information as an indicator of breeding success.
Prior knowledge acquisition
The observer re-familiarised themselves with the description and illustrations of Meadow Pipit and Skylark in ‘Collins Bird Guide’ (Svensson and Grant, 1999) and ‘RSPB Birds of Britain and Europe’ (Hume, 2002). ‘Collins Bird Songs and Calls of Britain and Northern Europe’ (Sample, 1996) was used as a guide to the songs and calls for these species.
Timing of visits
The site was visited on four occasions, evenly spaced (every two weeks) between mid-April and mid-June.
Survey routes
The routes were defined to satisfy the following criteria:
Routes should pass within 100 metres of all sightings recorded for both species between 1999 and 2010. This includes estimated locations from the 2001 survey (Swinney and Pearson, 2001)
Routes should align, as far as possible, with the transects employed in the 1992 survey (SWT, 1993)
Routes should follow existing paths
A survey route should take no more than 4 hours to complete.
From the application of the above criteria two survey routes were defined for the Park. A map showing the survey routes used and associated Way Points is provided in Appendix 1 of the full length document.
Survey mapping
Survey route Way Points were identified using Google satellite images, the points chosen coinciding with major features such as road junctions and where paths changed direction. Google Latitude and Longitude readings were converted to grid references by using the algorithm employed by Veness (Veness, 2005). Conversions and were calibrated against known reference points on the HSRS 1:2500 map of Holyrood Park.
Survey equipment
The following equipment was used by the surveyor:
Transect map (See Appendix 1 of the full length document)
Way point list (See Appendix 1 of the full length document)
A 1:10,000 map of the Park showing a 100 metre Ordinance Survey grid
Note book
Pencil and eraser
Binoculars (Swarovski EL 8.5 x 42)
Survey details recorded
Date
Survey start and end time
Field observer name
Weather conditions (Percentage of cloud cover, estimated temperature and estimated wind-speed)
Survey data collected
Location, count, behaviour and flight direction of Meadow Pipits and Skylarks seen was recorded in the observers note book. Locations were estimated within a 100 metre square by comparing observed ground features to the 1:10,000 map of the Park.
Behaviours were recorded, and subsequently ranked for analysis, based on the breeding behaviour analysis employed by the BTO (BTO, 2011) (See Appendix 2 of the full length document).
A table of counting methods by survey location is shown in the full length document.
Survey conditions
Surveys were carried out between 8 am and 12 noon in dry weather, with temperatures estimated to vary between 12 and 17°C. Wind speeds were generally between 1 and 2 on the Beaufort scale. These were considered to be in-line with those recommended for these species in ‘Bird Monitoring Methods’ (Gilbert, Gibbons and Evans, 1998), which states that cold, windy and wet days should be avoided.
Analysis methods employed
The number and location of territories for both species was estimated by producing a cumulative distribution map for each species, and then comparing the behaviours noted during the individual surveys.
For each species overall distribution has been expressed as a bubble chart showing:
Total number of birds recorded during survey versus
The total number of 100 metre squares in which they were recorded versus
The total number of 100 metre squares in which breeding activity was noted. Indication of breeding was taken from the behaviour table in Appendix 2.
Habitat preference was judged by comparing 100 metre squares used for territory against a National Vegetation Classification (NVC) phase 1 map of the Park (SNH, 2001).
Results
Survey results - summary
11 Meadow Pipit and 1 Skylark territory were noted during the 2011 survey. The estimated locations of territory centres are shown in Appendix 3 of the full length document. A buuble chart of the results is shown in this section of the full length document.
The best sign of breeding behaviour observed for Meadow Pipit during the survey was ‘Agitated’ behaviour, indicative of ‘Probable’ breeding on the BTO scale.
The best sign of breeding behaviour noted for Skylark during the survey was ‘Pair observed in suitable nesting habitat during the breeding season’, indicative of ‘Probable’ breeding on the BTO scale.
Additional data from 2011 casual records
Meadow Pipit
Meadow Pipits were recorded in Holyrood Park between 25th March and 28th October 2011. Singing was first recorded on 3rd April, with the last record of breeding behaviour being an ‘Agitated’ bird on 13th July. While no additional territories were identified from the casual records, the breeding status of Meadow Pipit for Holyrood Park was raised to ’Proven’ on the BTO scale by the observation of birds carrying food, and a recently fledged bird being fed by an adult.
On the 26th September a flock of 16 and a dispersed group of 11 Meadow Pipits was noted. This is in line with the previous year’s ‘late season’ flock of 28 on 23rd September 2010. It is debatable whether these totals reflect the end of season population for the Park as birds were seen moving through adjacent areas by the author at this time. As a result a numerical estimate of breeding success cannot be given.
Skylark
Skylarks were seen in Holyrood Park between 25th February and 7th November 2011. Singing was first recorded on 25th February, with the last record of breeding behaviour being a bird carrying food on 12th July. While no additional territories were identified from the casual records, the breeding status of Skylark for Holyrood Park was raised to ‘Proven’ on the BTO scale by this record.
Discussion
Discussion of methods
Timing of visits
Visits commenced on 17th April and ended on 31st May, with a two week gap between each of the four visits. This was in line with those recommended for these species in ‘Bird Monitoring Methods’ (Gilbert, Gibbons and Evans, 1998).
The survey methodology employed proved adequate in producing an estimate of the number of bird territories. A more complete picture of breeding status, if desired, would require a continuation of the survey into late July.
Time allowed was adequate in all cases.
Species identification
No issues noted.
Data analysis
Production of summary information and graphs was facilitated by using Microsoft Excel 2007 (Service Pack 2).
A decline was observed from a possible population of 25-30 territories in 1992 (SWT, 1993) to 11 territories, on the back of Salisbury Crags and near the top of Arthur’s Seat, in 2011. These territories were noted to coincide with a variety of habitats including neutral grassland mapped in the Park NVC Phase 1 Survey (SNH, 2001), a finding in-line with that of the 1992 survey (SWT, 1993). It should be noted that while the 1992 SWT survey was not species specific, and that their number of territories is an extrapolation from the peak number of 13 birds observed by using a transect based methodology, the author has found no reason to doubt their findings.
Such a decline in numbers would follow the UK and Scottish trend noted for this species (BTO, 2012). Nonetheless, where territories have been established, particularly the 5 on the back of Salisbury Crags, their proximity suggests that the average territory appears to be in the order of 100 metres across. This suggests a higher density than that noted on another UK grassland area (Hickman, 2010), and may not reflect the true shape of the territories on the ground. It should also be noted that these Salisbury Crags territories coincided with, and indeed filled, the only part of that grassland to have been recently cut.
Skylark
A decline was observed from a possible population of 10-13 territories in 1992 (SWT, 1993) to 1 territory, on the back of Salisbury Crags, in 2011. This territory was noted to largely coincide with an area of higher, acidic grassland mapped in the Park NVC Phase 1 Survey (SNH, 2001), a finding in-line with that of the 1992 survey (SWT, 1993). It should be noted that while the 1992 SWT survey was not species specific, and that their number of territories is an extrapolation from the 9 birds (all singing males) observed by using a transect based methodology, the author has found no reason to doubt their findings.
This decline seems to have taken place within the last 10 years, as the Holyrood Park 2001 Linnet, Skylark and Yellowhammer survey (Swinney and Pearson, 2001) identified Skylark territorial or other breeding behaviour at 16 locations within the Park, mainly amongst the grassy areas of Whinny Hill and on the slopes between Salisbury Crags and Hunter’s Bog. The author of this paper has a photographic record of a Skylark near the top of Arthur’s Seat in March 2005, arguably an early breeding season arrival, and recalls Skylark singing in that area in the early 2000s. Such a decline appears to follow that seen in other parts of the UK, rather than Scotland (where populations have remained steady), over the last 10 years (BTO, 2012); it also mirrors the decline of another grassland species, the Grey partridge (Perdix perdix), in the Park over the same period (Checkley, 2006). Certainly both species have withdrawn from areas such as Dunsapie Crag and the Crow Hill cultivation terraces, which have shown a marked accumulation of rank grasses and matted vegetation since the end of sheep grazing in 1979. Why other, visibly suitable, areas near the top of Arthur’s Seat are no longer used is unclear, it is possible that visitor pressure is more of an issue here.
Discussion of Visitor Management
The disturbance of ground nesting birds by dogs has been raised as an issue under the Scottish Outdoor Access Code by the Royal Society for the Protection of Birds (SNH, 2010), and as one specifically affecting grassland nesting birds by the Berkshire Buckinghamshire and Oxon Wildlife Trust (2010) at Greenham and Crookham Commons. Within Holyrood Park itself the author has observed dog-walkers and their dogs in all areas of the Park, and while the walkers frequent the major and minor paths some of their dogs often run free in the adjoining vegetation – sometimes well out of sight of the owner. From discussions with dog owners small mammals such as voles and rabbits are known to be taken, and the author has observed distressed bird behaviour near dogs during previous breeding seasons.
In order to help mitigate the problem of dog disturbance, ‘ground nesting bird’ signage, requesting that walkers keep to defined paths and keep dogs under close control, was put in place by HSRS at access points to the back of Salisbury Crags during the 2011 breeding season. The author noted that the behaviour of some regular dog-walking visitors changed during this period, in one case the visitor changing their walking route for the duration of the breeding season. Discussions with other regular visitors showed them to at least be aware of the issue of disturbance during the breeding season. It is to be hoped that this laudable approach to visitor management will have a long-term effect on visitor behaviour, and minimize the disturbance of these ground nesting species. It is further to be hoped that a blanket dog ban, such as that employed at Aberlady Bay in East Lothian, will not be needed.
Further Study/Work
A repeat survey should be carried out in 2016 to better understand the effect of mechanised cutting and visitor management.
Conclusions
Skylark populations in Holyrood Park have declined from 10-13 territories in 1992 to the point of loss.
The Meadow Pipit population in Holyrood Park appears to have declined from 25-30 territories in 1992 to11 (a decline of approximately half to two-thirds).
Proven breeding was demonstrated for both species in 2011, but with only one pair of Skylark present the survival of the Park population will depend on individual immigration.
Where positive grassland management is in place, i.e. the mechanised maintenance of areas of short sward, the Meadow Pipit can achieve good nesting densities in the Park, as long as visitor disturbance can be managed. While the absence of Skylark can be attributed to rank vegetation in some areas this is not a complete explanation.
