We completely understand the suspicion that sometimes surrounds 'citizen science' projects, especially where some form of subscription is involved. The year-round BTO Garden BirdWatch (GBW) certainly has scientific merit, with a sizeable publication record of peer-reviewed scientific papers. The survey relies on its robust and repeatable methods to collect large-scale information on how birds (and other taxa) use gardens and how this use varies over time, in relation to surrounding habitat, within garden practices and geographic location.

Although there is variation in the ability of individual participants, and in the amount of time they spend carrying out the recording, our statistical models typically include a site-effect, which enables us to control for this variation. From a statistical perspective, the sheer size of the project increases its robustness, since it is the underlying patterns that are important.

The survey is self-funded, through the generosity of its participants and without this funding we would not be able to operate such a scheme. GBW data feed into conservation indicators and have real value, allowing us to collect information for a habitat that is difficult to monitor. It is worth noting that the BTO is an independent and impartial research organisation. It does not campaign and it is well-respected for its rigorous scientific position.