Good news for garden birds

There has been some good news for garden birds of late; news that has, to some extent, slipped by unnoticed because attention has been focussed on more glamorous species. This is the addition of several garden birds, most notably dunnock, starling and house sparrow, to the Government’s list of species to receive priority conservation action. Known as the BAP list, where BAP stands for Biodiversity Action Plan, the list is one of a number of different tools that the Government uses to help it determine the best ways in which to deliver its conservation action within the UK. Periodic reviews of the status of each of our plants, animals and habitats, enable experts to assess which species are in greatest need of support. Central to this review process are the data collected through long-term monitoring schemes, each charting the changing fortunes of our wildlife.

Some 26 bird species were already on the list (following the first BAP review, carried out in 1995) and to these have been added a further 33. The inclusion of house sparrow and starling is particularly welcome; house sparrow numbers have declined dramatically over recent decades and our breeding population is now less than half what it was back in the 1970s. A similarly alarming decline has hit both our breeding and wintering populations of starling. That two species, so closely associated with Man, should be in such difficulties gives us fair warning of our impact on the environment around us. The reasons for their declines are not fully understood and their inclusion on the BAP list should help to direct more resources towards identifying the underlying causes. Once these have been identified, conservationists can set about trying to halt and, ultimately, reverse the declines.

A number of other species that frequent gardens were already on the original BAP list and it is interesting to see how being on the list has helped their status. In some cases, such as for song thrush, inclusion on the BAP list has prompted a great deal of research and this has seen a recovery in numbers in recent years – evidence that the system works. However, for certain other species more clearly needs to be done. The decline in bullfinch has continued, despite inclusion, but we now have a much clearer understanding of why the species is having such a tough time. One of the most important aspects of inclusion on the list is the establishment of a number of key targets. By using targets, it is possible to determine whether the resulting conservation action has been successful. It also provides a focus for the researchers, something to aim for and something by which they can measure their success.

Long nights hard on small birds

The long nights that we experience at this time of year can make things difficult for many of our birds. A combination of low temperature, reduced amounts of daylight in which to find food, and a general decline in the amount of food available, can all have a dramatic impact on smaller species. Small birds may need to expend more energy to keep warm and, with only small reserves of body fat, they have to spend much of a typical winter’s day searching for food. This food is vital to replace losses from the night before and to prepare for the night ahead. Great tits may easily lose five percent of their body weight overnight, with the amount of weight lost being greatest during periods of cold weather.

Watching my bird feeders has revealed a pattern to the order in which the different species arrive in the morning. As one of some 2,000 licensed bird ringers nationwide, I am frequently up before dawn to set the nets in which I catch small birds for ringing. At this time of day, I can already hear the calls of blackbirds and robins up and about before it is truly light. With the nets set, I operate a regular pattern of checking and emptying the nets every 20 minutes or so, fitting rings and taking various measurements before releasing the birds. The first birds to be caught are usually blackbirds and other thrushes, followed by various tits and the occasional dunnock. It is not until an hour or so after dawn that the greenfinches, goldfinches and chaffinches begin to appear in any numbers. Birds continue to arrive to feed through until mid-morning then it all goes rather quiet, with numbers not increasing again until the hour or so before dusk, presumably when individuals come in to top up before going to roost.

Intuitively, you might expect those species that most urgently need to top up their fat reserves to arrive first but other factors also come into play. For example, roosting behaviour may be important. Some species roost communally, sharing body warmth and reducing the amount of energy they have to expend to keep warm. While wrens can use nestboxes or roosting pouches, long-tailed tits prefer to roost together on a branch in the centre of a thicket. Dominance also plays a role, with less dominant species forced to feed at times when feeders are not being dominated by more aggressive birds like greenfinch or starling. Such factors influence the basic pattern and will change over time as birds respond to changing weather conditions. Recent nights have been relatively mild but, as we move further into the winter, lower temperatures may bring birds to our feeders that much earlier relative to dawn.

Be prepared for busy bird tables

There was ice on the car windscreen the other morning and a definite chill in the air. Another indication of the drop in temperature was an increase in the numbers of birds visiting my garden feeding station. In with the regular greenfinches, were chaffinches, blue tits and coal tits, attracted by the sunflower hearts that I provide throughout the year. Providing food in this way gives a good indication of the numbers of birds around and of the availability of ‘natural’ food in the wider countryside. Towards the end of summer there is a noticeable drop in the numbers of birds visiting the garden, as birds that may have been breeding locally move out into the surrounding farmland and woodland to exploit the autumn bounty of fruits and seeds. Evidence from the 16,000 gardens that participate in the British Trust for Ornithology’s Garden BirdWatch scheme shows that this autumn trough is a national feature, repeated in gardens up and down the country. It is only when the bounty begins to decline, that the birds turn to gardens and the food that we provide.

Just how early into the winter birds like siskins, chaffinches and bramblings move into gardens is, in part, dependent on the size of the seed crop produced by trees like beech and sitka spruce. In some years, when the seed crop is particularly large, there is little need for these birds to visit gardens but in those years when seed is scarce, they can arrive early and in large numbers. The size of the seed crops of these two tree species follows a roughly four-yearly cycle, a strategy that enables the trees to reduce the impacts of seed predators on their precious seeds, with years of peak seed production followed by a number of years of much smaller crops. It just so happens that this year the quantities of beech seed (known as beechmast) and spruce cones are both small, something that has seen siskins arriving in gardens across East Anglia earlier than they would normally appear. This hints at a busy winter ahead, with large numbers of finches usng garden feeding stations. Because there tends to be a degree of synchrony in the size of the seed crop across large areas, we are also likely to see increased numbers of birds arriving here from Scandinavian forests. If, as the weather forecasters are predicting, we end up with a severe winter then this too will increase the numbers of birds visiting gardens. Joining the finches will come farmland buntings and thrushes, seeking the food needed to get them through the worst of the winter weather. So now is the time to stock up on birdfood, prepare yourself for the winter ahead and the sight of busy bird tables.