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Counting garden birds

Lots of people keep casual lists of birds they see in their gardens. Sometimes these are written down but more often they are mental checklists - perhaps one for the species which they have seen in their garden; maybe another for the birds which they know have nested there. Nowadays, often with very little or no extra effort, the garden birders' checklists can be pooled and put to good useThere is nearly always a burning desire to share and compare this information with other like-minded people. Nowadays, often with very little or no extra effort, the garden birders' checklists can be pooled and put to good use - very often use of national conservation significance. In this feature we will see how.

Bird population monitoring

Male blackbird.A knowledge of the abundance and distribution of birds has always been a central tenet of understanding their ecology and conservation biologyA knowledge of the abundance and distribution of birds has always been a central tenet of understanding their ecology and conservation biology. Therefore organisations like the Royal Society for the Protection of Birds (RSPB), the Wildfowl and Wetlands Trust (WWT) and the British Trust for Ornithology (BTO) have been involved in counting birds virtually since the inception of each.

The BTO is the real national authority on bird population census and monitoring; organisations like the RSPB and the WWT have wider remits, including acquisition and management of nature reserves and conservation campaign management. These three organisations, and a host of smaller ones, carry out survey work (most often through the efforts of volunteers) on behalf of the Joint Nature Conservation Committee (JNCC). The JNCC is the body responsible for advising the government on matters pertaining to nature conservation.

The national government has a number of 'Quality of Life' indicators which point to the sustainability of our lifestyles in the UK. Several of these indicators relate to landscape and wildlife including population trends in a number of key bird species; so in theory, the results of bird census work are actually used to inform government policiesthe results of bird census work are actually used to inform government policies.

Traditionally, one of the greatest difficulties when counting animals has always been getting big enough 'sample sizes'. For example, when attempting to compare populations in different habitats, a considerable number of counts need to be made in areas of each habitat type in order to get enough results to stand up to statistical analyses. In recent years a new phenomenon known as 'citizen science' has emerged, powered, in part, through widespread uptake of internet technology. Citizen science is the name given to scientific studies when large numbers of people are asked to volunteer their observationsCitizen science is the name given to scientific studies when large numbers of people are asked to volunteer their observations. Normally the participants 'duties' are kept fairly simple; it is not appropriate to ask too much of large numbers of volunteers who don't have specialist training. Though fairly simple questions are normally posed, and answered, the large sample sizes mean that the results can be extremely valuableThough fairly simple questions are normally posed, and answered, the large sample sizes mean that the results can be extremely valuable. The RSPB's 'Big Garden Birdwatch' and the BTO's 'Garden Birdwatch' are prime examples of citizen science in action.

Garden Bird Feeding Survey

The Garden Bird Feeding Survey (GBFS) began in the winter of 1970/71 and is the longest running annual survey of garden birds anywhere in Europe (Toms, 2003). Between October and March every year, weekly counts are made of the birds visiting feeders in around 250 gardens. About half of the gardens which contribute are classed as 'suburban' and the other half 'rural'.

Female siskin and goldfinch on nyger seed feeder.

The GBFS has been one of the most important surveys in providing empirical evidence of the long-term decline in numbers of some of our most typical garden birdsThe GBFS has been one of the most important surveys in providing empirical evidence of the long-term decline in numbers of some of our most typical garden birds, like the house sparrow (Passer domesticus) and the starling (Sturnus vulgaris). Because it runs over the entire winter, it has also revealed a great deal about how birds utilise gardens over the course of the winter; for example showing that reed buntings (Emberiza schoeniclus) are most likely to be seen in gardens in the late winter when their winter diet of seeds may be running low on farmland.

The survey is organised by the BTO and, in some regards, can be regarded as a forerunner to the more recent 'Garden Birdwatch' (see below); however, unlike the 'Garden Birdwatch', this survey is not open to all: numbers of participants are limited.

Garden BirdWatch

A wren - one of our most charming garden birds. The BTO/CJ Garden 'Garden BirdWatch' is a true mass-participation survey in that it is open to all; indeed, the BTO claim that Garden Birdwatch is "the largest year-round citizen science project on garden birds anywhere in the World!"Garden Birdwatch is "the largest year-round citizen science project on garden birds anywhere in the World!" (Toms, 2003). In a couple of respects however, it is quite different from many other such surveys: firstly, participants make a small, but significant, financial contribution in order to administer the survey (currently around £12 a year); secondly, participants contribute records of their garden bird observations on a weekly basis throughout the entire year. This contrasts markedly with the RSPB's Big Garden Birdwatch, for example, which is conducted over a single weekend during the year.

This survey was launched late in 1994 and is therefore approaching its tenth anniversary. There are currently some 16,000 participants providing weekly counts of the birds using their gardensThere are currently some 16,000 participants providing weekly counts of the birds using their gardens up and down the country: that's an awful lot of data. These data are particularly valuable because they are teaching us about the year-round use of our gardens by birds and with such a good sample size, the contribution they can can make to our understanding of long-term population trends is very significant.

Big Garden Birdwatch

The Big Garden Birdwatch takes place over a single weekend every January and has done for 25 years now. It started as a bit of fun for junior members of the RSPB, but in 2001 it was opened up to all. The RSPB estimate that in 2004 over 400,000 people took part in the event, leading them to claim that the 2004 Big Garden Birdwatch was "the world's biggest ever bird event." the 2004 Big Garden Birdwatch was "the world's biggest ever bird event."

It's a shame that the BTO's Garden BirdWatch and the RSPB's Big Garden Birdwatch have such similar names: it can cause some confusion, but in fact, as surveys go, they could hardly be more different. Pied wagtail - a bird associated with the urban environment. Whilst the BTO's Garden Birdwatch is a continuous year-round garden bird monitoring program, the RSPB's Big Garden Birdwatch is an annual one-off; participants need only watch the birds in their garden for any single hour during the nominated January weekendparticipants need only watch the birds in their garden for any single hour during the nominated January weekend, counting the maximum number of each species seen together. The simplicity and undemanding nature of the Big Garden Birdwatch are the secrets to its success. Although the counts are simple, sample sizes in the hundreds of thousands mean that some very good science can be done using the results. Because so many people are counting birds at pretty much the same time up and down the country, we can get a reliable indication of the abundance and distribution of garden birds at the time of the survey and, comparing these year on year, make a valuable contribution to the monitoring of long term population trends.

Other national surveys of relevance to gardens

Apart from the surveys mentioned above, there are also a number of others relevant, at least in part, to garden birds. Those run by the BTO or RSPB are described on their excellent BirdWeb website. For example there are opportunities to contribute observations of garden birds to 'Migration Watch', 'The Breeding Swallow Survey', and 'The Nest Record Scheme'. Check out the website for details.

A relatively simple, though very interesting, survey that anyone can get involved in is that run by the UK Phenology NetworkA relatively simple, though very interesting, survey that anyone can get involved in is that run by the UK Phenology Network. Phenology is the study of the timing of natural phenomena such as budburst in trees and bird migration. Anyone can take part in this survey and you contribute as little or as much as you like. You can make a contribution just by noting the dates that you first see summer migrants or when certain birds are first seen nest building etc.

Getting involved

If you just want to dip your toe into the waters of garden bird surveys, the ideal place to start is with the RSPB's Big Garden BirdwatchIf you just want to dip your toe into the waters of garden bird surveys, the ideal place to start is with the RSPB's Big Garden Birdwatch. The actual counting will only take an hour of your time during one weekend in January and apart from submitting your results, which you can do either by post or on-line, that's it. For further details, just look out for information in the press and media during early January, or check out the RSPB website.

The gardener's favourite: the robin.

If you already make, or would like to start making, weekly counts of the birds using your garden, the BTO's Garden Birdwatch would be an ideal national survey for you to contribute to. You do not have to be an expert and the survey rules to not specify a set amount of time that must be spent watching and recording birds; all they ask is that your effort is consistent from one week to the next. You might just record birds seen over your breakfast or perhaps whilst gardening. Remember there is a small annual administration charge, but all participants receive a quarterly colour magazine called 'Bird Table'. To find out more about taking part, follow this link to the BTO's website: http://www.bto.org/gbw/GBW_PROJECT_INVOLVED.htm.

you will have the satisfaction of knowing that you are making a real contribution to the understanding of garden bird ecology Counting the birds in your garden can be tremendous fun, even if you only do it for your own benefit. But if you take that extra step to get involved with one or more of the 'citizen science' projects described above, you will have the satisfaction of knowing that you are making a real contribution to the understanding of garden bird ecology.

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