RSPB Garden Watch 2021 – A Local Perspective

THE BIG GARDEN BIRDWATCH 2021 – A LOCAL PERSPECTIVE

ED DOLPHIN FOR THE SID VALLEY BIODIVERSITY GROUP

1. INTRODUCTION

The RSPB Big Garden Birdwatch (BGB) is one of the largest citizen science projects in the world.  For the last 40 years, thousands of volunteers have submitted data on the birds visiting their garden at the end of January.  In 2020, nearly half a million people recorded nearly 8 million birds during the last weekend in January.  The study focuses on 15 of the most common species, but sightings of other species are recorded also.

Over the years, this data has allowed the RSPB to track major changes in the urban bird populations.  For example, it has recorded a 76% decline in Song Thrushes visiting gardens, while there was an increase in sightings of smaller bird species such as Long-Tailed Tits, Wrens, and Coal Tits, up by 14%, 13% and 10% respectively from 2019 to 2020.  Of course, the data is just the start.  It is used to plan work across the country to support our birds.

One of the most important impacts of the birdwatch is the raised engagement of the human population.  It becomes part of the ‘many small actions making a big difference’ effect that is one of the founding principles of the Sid Valley Biodiversity Group.  Having birds visit your garden is a true delight and the publicity around the BGB encourages people to make provision in their gardens that supports birds through the winter, they put out food, they provide access to water, and they create nesting sites.

The RSPB publishes national results that include identifiable county statistics.  The Sid Valley Biodiversity Group (SVBG) was interested to see how our valley compares.  Members of the public were canvassed through local and social media to collect data.  There were 28 responses, a small sample but sufficient to give a reasonable picture.  The national and county results for 2021 will not be published until April and so we use the 2020 results to evaluate the valley.

2. FINDINGS

2.1 Overall Figures

The RSPB headline is a top ten based on the total numbers of each species recorded, see Table 1.  As was said, the national count recorded nearly 8 million birds in half a million observations, but the RSPB do not publish individual species counts.  Our observers recorded 660 birds in 35 observations.

• The raw national data provides a mean average of 16.12 birds seen in each garden observation; we do not have the frequency nor species range for individual observations.  
• The Devon average is 16.32 birds per garden.  
• The Sid Valley was above the national and county average with 18.86 birds per garden observation.  This ranged from a single Woodpigeon seen in Alexandria Road to the 45 birds across 13 species seen in an hour in Salcombe Regis.

Nationally, 79 species were recorded, but that covers The Isles of Scilly to the Shetland Islands.  Although there is much similarity in the most common birds, House Sparrows, Blackbirds and Starlings are at various stations in the top 4 at both ends of the country, there are regionally distinct species.   In the Scillies, Collared Doves complete the top four, but it is Feral Pigeons in Shetland, and the Hooded Crows that are ranked 10th in the north do not feature at all in the far south. 

There were 69 species recorded in Devon gardens.  Nobody in Devon was lucky enough to have a Mute Swan, Gadwall or Great Crested Grebe land on their garden pond over the weekend.  We just missed out on Skylarks which were seen in Cornwall.  

Our 35 observations recorded 28 species, see Tables 3-5.  The species diversity in the valley’s gardens ranged from the single Woodpigeon mentioned above to the 17 species seen in a garden on the rural edge of the valley.  The average garden was visited by 8 different species in the viewing period.  The British Trust for Ornithology (BTO) has been running a much smaller garden survey for even longer than the BGB.  This is a year-round survey that shows large seasonal variation as some species migrate and nature provides richer food sources away from gardens.  A future SVBG project will investigate how the valley compares with the national picture in different seasons.

Table 1. The top 10 species by numbers observed

2.2 An alternative top ten

Some birds such as Robins are very territorial, and you rarely see more than one or a pair in a garden.  Others, such as Sparrows and Goldfinches, live in flocks, especially during the winter.  Moving around in a flock has an advantage for small birds.  If there is a predator such as a Sparrowhawk, being in a flock has two advantages, a statistical chance of not being the one eaten, and more eyes to watch out for danger.  The flock of more than a dozen mixed Tits and Goldfinches that visits one of the study gardens regularly throughout the winter demonstrates this.  The birds have a definite habit of landing in a nearby small tree and waiting.  Two or three of the flock at a time take it in turns to fly to the feeder for a 30 second feed while the others wait and watch.

The Sparrowhawks have also adapted to us feeding the birds.  One makes a daily visit to the same garden and has been seen to take birds off the feeder.  On one occasion, it tried to take a bird from the small tree but failed because the branches and twigs did not offer a space large enough to fly through.  It did not visit during the allotted time.

The BGB top ten is compiled according to total number of birds recorded, this favours the flock birds over the territorial species.  If you compile the top ten according to the number of gardens that recorded individual species, the picture changes, see Table 2.  We do not have the data to reorder the species in this way for the national results.

Table 2 Top 10 species by total count and percentage of gardens visited

If you compile the top ten by the number of gardens visited by individual species rather than the gross count of birds, the aggressively territorial Robin jumps from 7^th to 3^rd in the local data and the Great Tit, which is often solitary, climbs 3 places from 8^th to 5^th, while the gregarious House Sparrows drop from 2^nd to 6^th and the Goldfinches drop from 4^th to 10^th.  

This is a small sample and four double digit sightings, two each for House Sparrows (10 and 11 birds) and Goldfinches (18 and 10 birds), might skew the result, but the much more substantial county data reinforces the pattern.  In the Devon data, Robins jump from 9^th to 2^nd and the Great Tits from 10^th to 6^th.  House Sparrows drop from 1^st to 5^th and Goldfinches from 5^th to 9^th place.

Being a relatively small sample taken over a limited time slot, there is not the reliability to draw conclusions about the less common species.   As mentioned above, a Sparrowhawk is a regular visitor to one of the gardens, but it did not visit during the observation period.

Figure 3 in the data appendix shows the total counts for the 28 species recorded in the Sid Valley; Figure 4 shows the same data but ranked from most to least frequent.  Figure 5 shows the number of gardens visited by each recorded species; Figure 6 shows the same data ranked from highest to lowest number of gardens per species.

2.3 Individual species

There are two of the RSPB target species that are well down the rankings whether by number of birds or number of gardens, Collared Doves (25^th and 23^rd =) and Starlings (22^nd = and 23^rd).

When Collared Doves were first seen in the UK in the 1950s, they enjoyed a population explosion largely because of garden feeders and there was concern that they would become a serious agricultural pest.  Across southern England, the 2020 national data records them in 30-40% of gardens and they are ranked between 13^th and 18th in most individual counties.  They are ranked 16^th in the Devon data.

Starlings are ranked 2^nd nationally and 3^rd in the Devon data.  There is a winter flock of Starlings in Sidmouth that feeds on the cricket club grass most afternoons, perhaps this is one reason they do not need to visit gardens to feed.  

In the Devon data, Starlings (3) and Collared Doves (16) ranked very differently on total numbers, but they are very close if you look at the percentage of gardens visited, 28% and 26% respectively.  As with the local Robins and Goldfinches, the difference is between flock and solitary birds.  Analysis of the Devon data reveals that you would expect to see 74 Starlings in their 28% of 100 gardens but only 16 Collared Doves in their 26% of 100 gardens.

One result that did draw early attention was the success of Woodpigeons.  These birds have adapted to humans very successfully.  It is not clear when or why they were named as woodland birds, but they were birds of arable farmland almost exclusively one hundred years ago.  In the last 50 years there has been a significant shift as many Woodpigeons have taken up an urban lifestyle.

In 1995-97, the BTO scheme reported Woodpigeons in 40-60% of gardens.  Ten years later the reporting rate had gone up to 60-80% and currently Woodpigeons are reported in 80-90% of the BTO gardens in the UK throughout the year.  Fig.1 shows the change over time for the records in one garden in Hampshire.   

The Sid Valley results are in line with the BTO data, it shows Woodpigeons visiting 91% of the gardens.  Ours is a small sample, and the BGB national data is lower but still showing a very successful species, 78% of English observers recorded Woodpigeons in their gardens in 2020.  The figure for Devon was 73%.  The very rural counties such as Lincolnshire, Shropshire and Worcestershire are all in the mid-80s, but Wood Pigeons are no longer a rural species.  Largely urban areas of England are still recording in the mid to high 70s.  73% of Greater Manchester gardens were visited by Woodpigeons in the 2020 survey, Greater London 77%, South Yorkshire 78%, and 83% of the West Midlands gardens.

Fig.1 Woodpigeon visits to a single Hampshire garden 1998-2020

2.4 The gardens

We managed to collect data from 35 separate observations, but these were from 28 separate gardens (Figure 2) because some sites were observed on two separate days or at different times.  Including the repeated observations is valid as can be seen by the variation.  On the Saturday, one garden recorded 32 birds across 8 species, on the Sunday the same garden recorded 39 birds across 11 species.  Another garden recorded a single Great Tit on one day, but 6 different birds on the second occasion.

Observers for the national BGB enter details about their gardens such as whether it has trees, bird feeders and ponds, three things known to help birds.  Also, observers are asked whether the garden is rural or urban and the proximity to farmland and woodland.  This data can be analysed to measure the impacts on bird numbers or species diversity.  

Our gardens are mostly medium size town gardens, and the sample is too small to draw any significant conclusions.  It is clear that those gardens on the edge the town tend to have more birds, and this is where uncommon species such as Tree Creepers and Bullfinches were more likely to be seen.

We await the 2021 national data, and data from different seasons gathered by participation in the BTO scheme later in the year.  In the meantime, the RSPB and BTO have used their national data to provide plenty of advice on their websites if you want to support the local bird population, many small actions making a big difference.

Ed Dolphin

February 2021

3. Data APPENDIX

Table 3.  Species recorded in the Sid Valley 2021 Big Garden Birdwatch

Table 4. Total number of birds observed by species

Table 5.  Number of gardens where each species was recorded

Fig.2 Survey sites

Fig.3 Individual species count alphabetical

Fig.4 Individual species count rank order

Fig.5 Number of Sid Valley gardens visited by individual species alphabetical

Fig.6 Number of Sid Valley gardens visited by individual species ranked

Fig.7 The range of species diversity per garden

Fig.8 Range of sightings frequency

Take Part in the 2022 Birdwatch Survey

It’s on January 28-30 and takes an hour watching your garden.

Why not grab a coffee, watch the birds, record what you see and send us a copy? 

You can download the recording form here  

BIG GARDEN BIRDWATCH 2022, submission form to SVBG