During the last few decades, the population of British House Sparrows has declined by roughly half, causing great alarm among both scientists and the general public. However, the latest data from the British Trust for Ornithology's (BTO) Garden BirdWatch, suggests that the decline is levelling off in our gardens.

The decline of the House Sparrow has been dramatic, falling from around 12 million British pairs in the 1970s to between six and seven million pairs currently, with a greater reduction in population size in urban and rural areas, than in suburban ones. Given that gardens are thought to be a particularly valuable habitat for our House Sparrows, it is encouraging that the latest BTO Garden BirdWatch data indicate that numbers are stabilizing, which is also reflected in data from the wider countryside.

The reasons behind the decline very much depend on population location, as House Sparrows are fairly sedentary birds. Populations across Britain were affected by loss of nesting sites and food sources, especially the lack of invertebrates to feed their young. However, in rural areas, changes in farming practices are thought to have had a large effect but in urban and suburban populations causes were more complex and may have included increased competition with other birds and increased pesticide use in gardens.

Clare Simm, from the BTO Garden Ecology Team, said: "This complexity is also reflected in the factors that are driving the change in this delightful bird's fortunes. We are a nation of wildlife lovers and more people are now managing their gardens for wildlife, which will be benefitting our House Sparrows. There is also a greater awareness of clean feeding stations and in reducing garden pesticide use. The combination of these factors could be helping the House Sparrow to maintain its population."

This news does not necessarily mean that House Sparrows are out of danger, as the turning point has only occurred in the last few years. Clare Simm has recommended five simple things that anyone can do in their gardens to encourage House Sparrows:

• Let an area of your garden go wild to encourage insects
• Plant species such as hawthorn and Ivy which provide thick vegetation for House Sparrows to hide in
• Provide your birds with a home, using either a House Sparrow terrace or a group of nest boxes (with 32mm entrance holes) near the eaves of your house
• If you feed your birds, provide them with a suitable seed mix that includes large grains
• Regularly clean your feeding stations to prevent disease

You can find out more about the Garden BirdWatch on the BTO website.

Last winter was a trial for us all, and our garden birds did not have an easy
time of it either. The British Trust for Ornithology's (BTO) Garden Bird Feeding
Survey saw unprecedented numbers of birds driven into Britain's gardens in
search of food. As winter looms once again, an army of 'citizen scientists' is preparing to chart the changing fortunes of our winter visitors.

The combination of poor fruit and seed yields in the wider countryside last
autumn, and the long, cold winter that followed, brought unprecedented numbers
of birds to our gardens. Perhaps the most striking arrival was the number of Siskins visiting gardens in search of food — numbers last winter were more than double the previous five-year average — a response to very poor crops of Sitka Spruce and birch seed, which Siskins usually take in winter.

 While the stories emerging from individual winters are fascinating, it is the
quantity of information collected by the BTO's armchair birdwatchers since 1970
that has proved so important. These long-term changes hint at what the future
might hold for our gardens and their visiting bird communities. Garden
birdwatchers may be seeing less of 'common' species, such as Collared Dove, Song Thrush and Starling, which are disappearing from our gardens
quite rapidly. However, fortunes for other birds are improving with Bullfinch, Goldfinch and Great Spotted Woodpecker becoming regulars.

 As the nation hopes that this winter is not as long or cold as the last one,
a certain group of birdwatchers are probably in two minds. For those who
participate in the BTO's Garden Bird Feeding Survey (GBFS), it is time to dust
off their notebooks and start recording from the warmth of their living
rooms.

Clare Simm of the BTO Garden Ecology team shares her thoughts as to what may
happen this winter: "With an unusually late start to the breeding season this
year, and a slow move towards the warm weather, it is difficult to predict
exactly how our birds will be faring as they enter the winter months. If this
winter is anywhere near as cold as last, then we might expect a sudden influx
into gardens once the autumn seed and berry stocks are depleted. One thing is
for sure, our 'citizen scientists' will be the first to notice and tell us."

 For a free guide on what to feed your birds this winter, information on how
to become a citizen scientist with the BTO and the opportunity to contribute to
valuable work like this, email [email protected],
telephone 01842 750050 or write to GBFS, BTO, The Nunnery, Thetford, Norfolk,
IP24 2PU.

A question that the British Trust for Ornithology's (BTO) Garden Ecology Team hears a lot at this time of year is "Where have all my birds gone?"

One of the most conspicuous disappearances from British gardens at the end of the summer is that of the Blackbird. For a bird that features in the majority of British gardens, the sudden loss of 'your' local Blackbird must come as quite a shock. But all is well. As results from the BTO's weekly Garden BirdWatch (GBW) survey show, it happens every year — there is always a pronounced 'trough' between September and October when Blackbirds are more absent from people's gardens.

So, where are they going? The answer is twofold. Your Blackbirds may have been looking a bit tatty towards the end of the summer because they have been frantically feeding their chicks, squeezing in and out of hedges. At the end of a busy breeding season they moult into new feathers. Individuals tend to hide away while they do this in order to avoid predators as they expend a lot of energy during the moulting process and are less manoeuvrable on the wing.

The second reason for their absence is that Blackbirds head out of gardens to take advantage of the natural food bounty in the wider countryside. During the autumn, Blackbirds feed up for the winter and the abundance of natural fruits, like blackberries, provides what they need. This use of natural fruits during the autumn has also been reflected in the GBW results from 2012. There were many more Blackbirds seen in gardens in autumn 2012, echoing the poor berry crop of last year.

You may miss your Blackbirds but they will start to head back into your gardens later on in the year. However, they may not return alone. Clare Simm, of the BTO Garden Ecology team, explains why: "When our British Blackbirds return to our gardens in the winter, they are often joined by immigrants. Large numbers of Blackbirds migrate from Sandinavia and continental Europe to spend the winter here in Britain and Ireland. A few of our Blackbirds migrate too, but generally only moving within Britain, often moving south and west during the autumn, pursuing the milder weather."

Birds might be paying more attention to road speed limits than some humans: a
new study has found that some European birds factor in average traffic speeds
when determining when they need to take off to avoid oncoming cars. In the
study, published in this week's issue of the journal Biology Letters, scientists tested whether European birds standing on the side of the road
altered their escape distances in response to how fast an approaching car was
moving or to road speed limits. The abstract can be found below:

 Behavioural responses can help species persist in habitats modified
by humans. Roads and traffic greatly affect animals' mortality, not only through
habitat structure modifications but also through direct mortality owing to
collisions. Although species are known to differ in their sensitivity to the
risk of collision, whether individuals can change their behaviour in response to
this is still unknown. Here, we tested whether common European birds changed
their flight initiation distances (FIDs) in response to vehicles according to
road speed limit (a known factor affecting killing rates on roads) and vehicle
speed. We found that FID increased with speed limit, although vehicle speed had
no effect. This suggests that birds adjust their flight distance to speed limit,
which may reduce collision risks and decrease mortality maximizing the time
allocated to foraging behaviours. Mobility and territory size are likely to
affect an individual's ability to respond adaptively to local speed
limits.
Study co-author Pierre Legagneux, a biologist at Canada's University of
Quebec in Rimouski, said the idea for the experiment occurred to him while he
was commuting to his lab in France. "I found [the commute] very boring so I had
to do something while driving, so I started to record birds flying away,"
Legagneux said. Using only a stopwatch and a notebook, Legagneux measured the
reaction times of birds that he spotted on the edge of the road while travelling
in regions where the speed limit ranged from about 12 to 70 miles per hour (20
to 110 kilometres per hour). "When the birds flew away, I started my timer and I
fixed the point where the birds were standing. And when I passed over this
point, I stopped my timer," Legagneux explained. "So I had the time elapsed, and
because I also recorded our vehicle speed, I also had the distance."

 Legagneux and his colleague, Simon Ducatez of Canada's McGill University,
found that the birds — mainly Carrion Crows, House Sparrows and Blackbirds — took flight earlier after spotting
their car in areas where the speed limit was higher. Curiously, the birds did
not seem to pay attention to the car itself. "They reacted the same way, no
matter the speed of the car," Legagneux said.

 The scientists speculate that some combination of two things might be
happening. First, it may just be a case of natural selection in which
individuals that failed to take off quickly enough are killed. As a result, only
those birds with traits that help them successfully escape oncoming traffic go
on to reproduce. Another possibility, Legagneux said, is that the birds are
actually learning to adapt to different traffic speeds. Daniel Blumstein, a
biologist and bird behaviourist at the University of California, Los Angeles,
said he could easily see how learning might be taking place. Imagine, he said, a
scenario in which a bird is foraging next to the road and a truck drives by. "If
the truck is moving fast, the bird is going to get knocked around by the
vortices coming off that truck" said Blumstein. "So the bird, if it survives, is
going to learn very quickly that the truck produced a very adverse experience...
One or a few trials of getting knocked around may be sufficient for the bird to
learn that cars are approaching faster on certain roads than other roads."

 But why did the birds seem to ignore the speed of the scientist's car itself?
It's possible, Legagneux said, that the birds might have just learned that it's
simpler to react the same way for any given section of road. "This way, they are
not spending a lot of time being vigilant by looking at the speed of each car,"
he said. Legagneux added that the findings have implications for making roads
safer for wildlife. "If you have different speed limits for similar roads in
similar landscapes, it could be dangerous for birds because they hardly have any
cues of those changes."