Why's my garden pigeons and magpies, and not smaller birds?
This is most likely a coincidence caused by any number of reasons. Pigeons and magpies are more adaptable to the man-made changing conditions in towns than smaller birds. They are also large and dominant, so many other birds may prefer to keep out of their way rather than compete with them for food.
Although large numbers of pigeons can keep smaller birds off bird tables by their sheer size and number, they don't predate chicks or adults of other birds. Magpies are omnivorous, and despite taking eggs and chicks of other birds, only 10 per cent of their diet (at most) involves birds.
Extensive research has failed to find evidence that magpies are the reason for the declines in bird populations. House sparrows and starlings are both declining in number, even though their nests in holes and other cavities are safe from magpie predation, while chaffinches and greenfinches, which build open cup nests vulnerable to predation, are doing well.
I'm in London, why are there are no sparrows?
House sparrows are declining seriously across parts of the UK as a result of changes in the wider countryside, especially in farming methods. Around 60 per cent of house sparrows have been lost since the mid-1970s. The declines have been particularly acute in centres of large cities including London, Edinburgh and Glasgow.
This is of particular concern since the house sparrow is one of very few species that actually thrives with close proximity to people, even in city centres. We're conducting a programme of research into sparrow decline.
The early indications are that, yet again, the cause is food availability at some parts of the year and availability of nesting sites. Since house sparrows are sedentary and rarely move far from their birthplace, it can take a long time for them to return to areas from where they've disappeared.
Swallow nests have declined in my outbuildings. What's the problem?
There is anecdotal evidence to suggest that swallow numbers are declining in many areas across the UK.
It's believed that changes in their breeding grounds are responsible. As more farm buildings are converted and modernised, suitable nesting sites become scarcer. Swallows feed on flying insects, which are plentiful especially in wetland areas and pastures. As more grazing land is converted to arable land, there are fewer insects for them to eat and feed to their young.
As swallows do not go far from their nest to forage, nesting and feeding areas must always be close together. Dry weather in early summer may result in lack of mud for building and repairing their nests, and effectively prevents them from nesting, or forces them to move elsewhere.
A regular visitor hasn't bred this year. Are they declining?
Not necessarily. Birds don't always use the same nest site every year. Reasons include:
A territory may not be occupied every year.
A nest site may be vacated if the birds have found an alternative nest they prefer within the same territory (eg a neighbour has put up a new nest box), or trees or shrubs that were the key feeding source have been removed in your, or your neighbour’s garden. Without a food source a territory is useless.
Birds may divide their territories in a different way, resulting in your garden getting less attention than in previous years.
