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.

It is a question people have pondered for centuries: how do migrating birds
navigate between breeding and wintering grounds? Do they have some genetic GPS
to steer them along time-honoured routes, or do they learn the way from parents
or elders in migrating flocks? New research shows that, in the case of the
endangered Whooping Crane of North America, the birds do learn routes from older and more experienced companions — and all of them become better at navigating with age and experience.

University of Maryland ecologist Thomas Mueller and colleagues took advantage
of eight years of detailed migration data compiled on birds bred in captivity
and released in Wisconsin's Necedah National Wildlife Refuge for a journey to
their Florida breeding grounds. Flying groups that include a migration-savvy
seven-year-old crane veer off course 38% less often than groups in which the
oldest birds are only a year old, according to an eight-year study of Whooping
Crane migration between Wisconsin and Florida. On average, the one-year-olds
that don't follow older birds veer off the flight path by 60 miles (97km). But
the cranes' migration ability improves steadily with age, the study shows.
Groups with even one of these older birds deviate less than 40 miles (64km), on
average, from the most efficient route.

 Other likely variables for navigation success, including gender and the size
of flying groups, appeared to make no difference in the results. Mueller, a
co-author of the study, and his team theorized that the older birds recognize
landmarks better and may also know how best to cope with bad weather — two
skills they apparently pass on to the young birds that follow their lead. "As
the oldest bird in the flying group gets older, it seems that there's dramatic
improvement in its migratory efficiency for about the first five years," Mueller
said. "There is a very big difference if the oldest bird in a flying group is
one or two years old or if it's five or six or seven years old. A bird can be
pretty young and still have great success," he added, "as long as it flies with
a bird that is pretty old."

What's new?
Previous studies have suggested that learning plays some role among migrating
species. However, as Mueller cited, what is new here is that learning takes
place over a number of years and the older birds are crucial to the development
of the younger birds. Mueller explained: "That was difficult to look at before
because the data simply didn't exist. Usually tracking data on animals lasts for
a year or two years if you're lucky."

As part of unprecedented efforts to save and reintroduce the species,
scientists collected data to gauge the success of breeding, training, and the
birds' subsequent 1,300-mile (2,100km) migration. Individual birds were
identified and tracked with satellite transmitters, radiotelemetry, and human
observers. "Usually you don't even know if a bird is two or three or four years
old," Mueller continued. "There are lots of [previous] comparisons between
juveniles and adults, but here we had the full progression of many years as well
as the information of how old the birds were, how they were related to one
another, and exactly where and when they migrated."

What does this mean?
The Whooping Crane research is important new evidence showing how bird
migration is, at least in part, a learned skill. But it won't put to rest the
long-running debate on the respective roles played by genetics and social
learning.

 In fact, Mueller said, the study suggests an interesting combination of
genetics and learned behaviour at work. It begins when the time comes for the
cranes' first autumn flight to their southern wintering grounds and the
captive-bred animals are actually guided by humans who fly ultralight aircraft
all the way to Florida. "If you think about even that initial migration, it
needs to be at least somewhat learned," he explained. "They may have a natural
tendency to migrate in the fall, but we don't think many would get anywhere
where they could survive without some training."

 But genetics do begin to play a more easily visible role on the return trip,
he added. "Then after they've been shown the route once, in the spring they know
it's time to initiate a return and there's a genetic component in play there.
Because nobody has showed them this, so it's genetics combined with the learned
knowledge from the trip south in the fall."

 What's next?
Co-author Sarah Converse, a research scientist with the U.S. Geological
Survey's Patuxent Wildlife Research Center, has worked extensively with the
Whooping Crane Eastern Partnership, which runs the eastern migratory population
reintroduction program. She said: "Our results suggest that an effort to restore
Whooping Crane populations isn't just an effort to restore a biological
population, but also an effort to restore a culture, where knowledge is
transmitted across generations via learning, rather than genetics."

 "We can imagine that the low breeding success that we are currently
struggling with in this reintroduced population might actually improve over
time, with increased experience and learning of appropriate breeding behaviours.
For example, maybe chicks learn from their parents how to themselves be
successful parents. Overall, these results suggest that patience may well be
important if we hope to restore migratory Whooping Cranes to eastern North
America."

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.

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."

Recent surveys on its coastal Patagonian wintering grounds indicate that the
Endangered Hooded Grebe Podiceps gallardoi has declined by 40% in
the last seven years and this, along with alarming new threats detected on its
breeding grounds during 2011, indicate action is now urgently required to
prevent the rapidly increasing threat of its extinction.

 In response to these worrying findings, Aves Argentinas (BirdLife in
Argentina) has mounted a wide-ranging offensive to protect this
highly-threatened migratory species from further decline. In support, we are
launching an international online appeal through the BirdLife Preventing
Extinctions Programme to help fund the urgently required conservation
action that they have already begun.

 Please click here to visit BirdLife International's 
appeal page and see a video of breeding Hooded Grebes filmed by our
conservation team last week.

  Discovered only as recently as 1974, Hooded Grebe has declined by as much as
80% in the last 30 years and as a result of surveys conducted in 2006 and 2009,
the species was uplisted by BirdLife to Endangered on the IUCN Red List in
May 2009. Recent counts on the wintering grounds last year, suggest the decline
is steepening further.

 “Our teams started to become really worried when we realised that
there was more than one cause to tackle if we were to conserve the Hooded
Grebe”, said Gustavo Costa, President of Aves Argentinas.

In many of the lakes in the grebe’s core distribution, exotic trout have been
introduced for industrial fish production. “Trout rearing has reached the most
isolated places, and this industry is threatening not only the future of the
grebe but also the rest of the wildlife present in those environments”,
Gustavo Costa added. Also evident are the increasing numbers of Kelp Gull
Larus dominicanus, a known predator of the grebe that has benefited
from both the fish industry and poor waste management at human settlements.

As if these problems were not already enough to push this struggling species
over the edge, a breeding colony which Aves Argentinas was studying at Laguna El
Cervecero, Santa Cruz Province in March 2011, was devastated by a sinister
and ferocious invasive pest that is now advancing in western Patagonia: the
American mink, Neovison vison. More than 30 breeding adult Hooded
Grebes were found killed by mink at this one site, and a further 40-plus eggs
were abandoned.

 “This was one of the saddest days in my life as a naturalist, but at least it
meant that we had discovered another reason for the Hooded Grebe’s decline – and a very frightening one at that – that could allow us to implement suitable
management actions in the field”, said Kini Roesler, a field biologist who is
doing his PhD on the species.

 As part of the immediate conservation action Aves Argentinas is coordinating,
a team of scientists and conservationists including staff from Aves Argentinas,
Ambiente Sur and CONICET are currently in the field attempting to prevent
predation at several known colonies this breeding season. Measures to
control mink and reduce predation by gulls are being prioritised and wherever
breeding populations are located, they plan to set up ’round the clock’ watches
to protect the nesting birds.

Climate change is also a major threat to this species and its habitat: anecdotal reports suggest that recent winter snowfall has been much reduced, without a corresponding increase in precipitation at other times. Many of the lakes surveyed last year were found to be dry or becoming clogged with silt as a result of the general desertification of the region, leading to changes in the composition of the water.  Water levels at known breeding sites were 2-3 m lower than in previous years.

 Recent investigations indicate that wind gusts have also significantly
increased in recent decades. Unseasonably strong winds have caused around
50% of all breeding attempts to fail in the last three years. At other
times this threat would be marginal; with adult mortality naturally very low,
the species may be adapted to survive a succession of poor breeding seasons.
But, with numbers now so reduced and still falling so rapidly, the loss of
entire breeding colonies to wind damage could have a much greater impact.

 A stark shadow was cast over Aves Argentinas’s findings when, in May 2010,
the Alaotra Grebe Tachybaptus rufolavatus of Madagascar was declared extinct. This was the third known grebe extinction since the last quarter of the 20th Century, after the Colombian Grebe Podiceps andinus and Atitlan Grebe
Podilymbus gigas, and followed news that the Critically Endangered Junín Grebe Podiceps taczanowskii, which already had a population of fewer than 250 individuals, had suffered a further population decline.

 “This is why we are developing an action plan for the Hooded Grebe, that
involves research, pest control and advocacy at every level”, said Dr. Andrés
Bosso, Director of Aves Argentinas’ International Co-operation Programme.
 An initial meeting to develop a species action plan took place at Aves
Argentinas’s headquarters, in July 2009, and brought together specialists from
Ambiente Sur, Aves Argentinas, and Fundacion Vida Silvestre Argentina who are
now working closely together.

 “We need to strengthen the protected areas system in the region”, Andrés
Bosso added. “Eight Important Bird Areas (IBAs) contain the species, but only
one is fully protected.” Laguna Los Escarchados, the site where Hooded Grebe was
discovered in 1974, was declared a reserve in 1979, but is now known to
only hold a marginal population. Key breeding lakes in the core of the
grebe’s range lack any kind of legal protection, though the population
stronghold on Meseta de Strobel is still afforded some protection by its
remoteness and inaccessibility.

Aves Argentinas has been appointed official BirdLife Species Guardian for Hooded Grebe and is seeking funding for a range of urgent actions that are already in progress to  ensure the survival of the species. These include implementation of summer and  winter surveys and predator control in 2012, 2013 and 2014, embracing the  entirety of the Buenos Aires, Asador, Las Vizcachas, Viedma, Cardiel and Strobel  plateaus, the Coyle and Gallegos estuaries, and any of the plateaus reachable in  winter. Surveys are also now being carried out on previously unsearched plateaus.

 A number of local conservation agents are also being assigned to the
species’ breeding and wintering grounds to execute a monitoring plan and
implement the needed conservation measures.

 The programme to eradicate mink, control Kelp Gull numbers on the breeding
grounds, and help protect breeding sites from strong winds has already begun in
earnest. Farm-workers will be encouraged to become local “Hooded
Grebe Guardians”, monitoring the presence or absence of the birds, and give
Aves Argentinas early warnings of potential new threats to the species.
Conservationists are also seeking agreements with landowners on the plateaus to
purchase and/or protect their properties as private reserves.

 Ringing/banding and satellite tracking will be used to improve knowledge of
the birds’ movements, and determine where juvenile Hooded Grebes spend the
winter.

 A national campaign to raise awareness of the Hooded Grebe and its
predicament among the Argentinian public is also planned, with an additional
goal of having the bird declared an official National Monument. A team from
Aves Argentinas is currently in the field overseeing the filming of a Hooded
Grebe documentary which will be used in this campaign. This production is
being supported by the Argentine Ministry of Tourism.

 There is clearly much to be done if the fortunes of the remarkable Hooded
Grebe are to be turned around. A robust plan is in place and work has already
begun but significant funding is now urgently required to deliver this ambitious
project and achieve long-term success.

 Every little helps and every one can join in. If you would like to help save
the magnificent Hooded Grebe from slipping away, within just four decades of its
original discovery, please click here to make a donation online
today.

In striking contrast to last week's report on the relation between feeding and the reproductive success of Great Spotted Woodpeckers, new research1 claims that feeding wild birds during the winter could harm the success of any chicks born in the following spring. Scientists carried out the study on nine sites across Cornwall, where over three years they supplemented the Blue Tit population's winter food with nothing, balls of fat, or fat enriched with vitamin E. Nest boxes at the sites were then checked the following spring to assess how the number of eggs, and the size and success of any chicks, related to the amount and type of extra food provided.

The study, published in Scientific Reports, found that when extra food was given Blue Tits produced smaller chicks, which had a lower chance of survival than the chicks that didn't receive any additional food. Dr Jon Blount of the University of Exeter, who led the research team, explained that, "Although the precise reasons why fed populations subsequently have reduced reproductive success are unclear, it would be valuable to assess whether birds would benefit from being fed all year round rather than only in winter".

Supplementing birds' sparse winter diet with commercially available food is common in the UK and USA, with more than half a million tonnes of commercial bird feed sold each year in the two countries. Vitamin E was used in the study for one test group as it is often found in bird food such as seeds and nuts. Previous studies have shown that giving wild birds additional food can have an almost immediate benefit to their survival, and can enhance future breeding success. Dr Kate Plummer of the British Trust for Ornithology, who is first author of the research, says that a possible reason for the findings is that extra food helps birds who would not otherwise have survived to breed. The poor condition of these birds means they can only raise a small number of chicks.

Whether providing food is detrimental or beneficial to wild bird populations, it is clear that more research is needed to better understand its effects. Blount concluded that "More research is needed to determine exactly what level of additional food provisioning, and at what times of year, would truly benefit wild bird populations."

The paper's abstract is as follows:

"Supplementation of food to wild birds occurs on an enormous scale worldwide, and is often cited as an exemplar of beneficial human–wildlife interaction. Recently it has been speculated that winter feeding could have negative consequences for future reproduction, for example by enabling low-quality individuals to recruit into breeding populations. However, evidence that winter feeding has deleterious impacts on reproductive success is lacking. Here, in a landscape-scale study of blue tits (Cyanistes caeruleus) across multiple years, we show that winter food supplementation reduced breeding performance the following spring. Compared to unfed populations, winter-fed birds produced offspring that weighed less, were smaller, and had lower survival. This impairment was observed in parents that had received fat only, or in combination with vitamin E, suggesting some generality in the mechanism by which supplementary feeding affected reproduction. Our results highlight the potential for deleterious population-level consequences of winter food supplementation on wild birds."

The British Trust for Ornithology (BTO) hopes to answer one of British ornithology's greatest mysteries using the very latest that technology has to offer in a project starting this summer. The House Martin is well known to many people; from April to September it lives cheek by jowl with those lucky enough to have this energetic little bird nest under their eaves. In recent years, however, the number breeding here in the UK has fallen by two thirds, leading to the species being Amber-listed as a bird of conservation concern and in need of help.

Though we know a lot about the breeding ecology of the House Martin in the UK, once September arrives and this enigmatic bird heads off south for the winter it virtually disappears from our radar. It is not known where in Africa House Martins winter, or how precisely they get there. If ornithologists are to start understanding what is driving the decline of the martins, then it is these questions that will need to be answered.

This summer, the BTO aims to use the latest technology to discover the routes that House Martins take to Africa and to find out exactly where they spend the winter months. BTO researchers plan to do this by fitting a tiny (shirt button-sized) device known as a geolocator to each bird. Weighing less than a gramme, the device contains a clock, a calendar and a light sensor, together with enough memory to store all of the data collected from the day it is fitted until the day it is retrieved.

By comparing daylight length, as measured by the light sensor, with the time and date recorded, scientists at the BTO are able to determine where on the planet the device was at any given time. This information will then reveal the wintering areas, together with the location of possible stopover and refuelling sites, precise migration routes and the timing of the migration through Europe and Africa.

Paul Stancliffe of the BTO commented, "I have long dreamed of being able to follow a bird like the House Martin on its migration from Britain to Africa, to get a glimpse of the places it is passing through and the places that it chooses to stay and rest for a while before continuing on its journey. It is very exciting to think that we are on the brink of new discoveries that should help these delightful birds and provide them with a more optimistic future. This technology comes at a price and we need help to secure enough of them to make the project worthwhile. Anyone interested in seeing how they might be able to help can find out more by visiting www.bto.org. Each device costs £170 and we hope to be able to fit them to at least 20 birds. We need help to support the scientists developing this project."

For more information please visit http://www.bto.org/volunteer-surveys/house-martin-survey/movements.

The RSPB is calling on farmers and birdwatchers to help locate the UK's rarest nesting bird of prey: the Montagu's Harrier. The population of this beautiful bird of prey is down to fewer than a dozen pairs, most of which nest in crops. The organization is appealing for sightings in an attempt to locate and protect their nests, which are often hidden away in lowland crops and often only found at harvest time.

Montagu's Harriers return to the UK in late April after spending the winter in Africa. They breed almost entirely in the southwest and east of England on lowland farmland, particularly choosing winter cereals, oilseed rape and grass silage. The core population often returns to the same nesting locations each year and RSPB has been working successfully with the associated local farmers for over 30 years to protect the species.

Mark Thomas, who leads on the species' work for the RSPB, said: "Along with species like Stone Curlews and Corncrakes, farmers have been essential in conserving our tiny population of Montagu's Harriers and through this hotline we hope to locate additional pairs that may otherwise have been missed. The UK population is currently teetering on the brink, and finding additional pairs will be a bonus. All reports will be treated in the strictest of confidence. We're hopeful that farmers and birdwatchers who spot the harriers will contact us so that we can confirm the sightings. We can offer free advice on how these sites can be protected to ensure these magnificent birds can successfully rear young."

Anyone who thinks they may have seen a Montagu's Harrier is urged to contact the hotline on 01767 693398 or email [email protected]. Details should include the date and six digit grid reference, if possible, and a contact telephone number.

RSPB
Friday 31st May 2013