Italian sparrow joins family as a new species

Scientists in Norway say they have conclusive genetic evidence that sparrows recently evolved a third species.

The Italian sparrow, they argue, is a cross between the ubiquitous house sparrow and the Spanish sparrow.

Whether it is a distinct species has been the subject of a long scientific debate.

The Oslo team say in the journal Molecular Ecology that their evidence resolves the question.

Many bird-watching guides already identify the Italian sparrow as a separate species.

But this study, led by evolutionary biologist Glenn-Peter Saetre from the University of Oslo, is a genetic snapshot that appears to settle the debate.

The researchers studied populations of Italian and Spanish sparrows that share the same habitat in the south-east of Italy.

They took blood samples from the birds in order to extract DNA.

"By examining the genetics, we have shown conclusively that the Italian sparrow is of mixed origin - it is a hybrid of the house sparrow and the Spanish sparrow," Dr Saetre told BBC Nature.

"Second, and perhaps equally important - it is not reproducing with the Spanish sparrow, even though the two birds live side-by-side."

If the birds had been breeding, the scientists say that they would have found genetic "intermediates" - birds with genes from both species.

"But we didn't find this, so we think [the two species] have formed some kind of reproductive barrier to each other," Prof Saetre said.

"Either the [Italian sparrows] just don't like the look of the [Spanish sparrows] or perhaps they have evolved a different breeding season.

"We're not sure what the reason is, but they are not reproducing."

In evolutionary biology, the definition of a distinct species is not entirely clear-cut.

William Amos, professor of evolutionary genetics at the University of Cambridge, explained: "I think the best definition we have is the one that says that different species are those that, under natural conditions, tend not to interbreed.

"Because as soon as you have interbreeding, all those barriers [between those groups of animals] break down."

If Italian sparrows have indeed stopped reproducing with Spanish sparrows, they will gradually, generation by generation, become even more genetically distinct.

As well as providing strong evidence of this rare event - termed speciation - the scientists believe the research shows that the crossing of two species to form a new one might be "more common in nature than previously assumed".

By Victoria Gill Science reporter, BBC Nature
http://www.bbc.co.uk/nature/14947902

Mystery of the vanishing sparrows still baffles scientists 10 years on

The greenfinch may be declining because of a parasitic disease, but nobody knows – still – the reason for the decline of the house sparrow.

It was once our most common and familiar bird. Now, in many places, it has vanished. Yet, more than 10 years after The Independent offered a prize of £5,000 for a proper scientific explanation of the house sparrow's widespread disappearance from many of our towns and cities, London above all, its vanishing remains one of the great environmental mysteries.

Yesterday, for example, there were no sparrows visible in London's Trafalgar Square, whereas 25 years ago the major tourist destination scattered with sandwich crumbs was full of them – as similar sites in major cities around the world are full of them still.

In the 1990s London's house sparrows entered a sudden and sharp decline until, by the turn of the century, they had virtually disappeared from the capital – the last pair of sparrows in St James's Park, packed with other birds, nested in 1998.

When this newspaper launched its "Save The Sparrow" campaign on 16 May 2000, it made international headlines. The fact that the cheeky "Cockney sparrer", the street smart urban survivor par excellence, was no longer surviving in urban habitats, caught people's imagination, not least because their disappearance may resemble the miner's canary – a warning of some unknown and wider danger. If something in the urban environment was devastating sparrows, what was it doing to us?

However, we did not succeed immediately in drawing out definitive explanations. Suggestions for the reason behind the decline ranged from the increase in suburban predators such as magpies, sparrowhawks and cats to the trend in "tidying up" houses and gardens leaving fewer nesting spaces. Disease, mobile phone radiation and insect decline were also posited.

It was not until 2008 that we had a serious entry for the prize, for which the rules were fairly stiff – the explanation had to be in a paper published in a peer-reviewed scientific journal, and accepted by our referees, the Royal Society for the Protection of Birds (RSPB), the British Trust for Ornithology, and the world expert on sparrows, Dr Denis Summers-Smith.

The 2008 entry was based in the work of a young postgraduate student, Kate Vincent, whose 2005 PhD thesis at De Montfort University in Leicester showed that sparrow chicks in some places were dying of starvation in their nests because of the lack of suitable insect food, such as aphids.

Her data, analysed intensively by senior ornithologists led by Dr Will Peach of the RSPB, formed the basis of a paper in the journal Animal Conservation which was submitted for the prize. But of our three referees, one thought it merited the award, one thought it did not, and one thought it merited half the award. It was certainly a serious contender, but as it was possible that another entry might secure the prize unanimously, we felt the award should be held back.

The other entry, submitted earlier this year from Christopher Bell, an independent scientific researcher, and other scientists, was published as a paper in the online version of Auk, the journal of the American Ornithologists' Union, and suggested that the cause of the decline was predation by sparrowhawks. It was rejected by all three referees.

In March, Dr Summers-Smith circulated a note to researchers interested in the sparrow's disappearance, summarising all the theories and suggestions of the last 10 years. His own view is that insect decline, leading to chick mortality, is "a primary factor" but as he says himself: "It is a necessary, but not a sufficient condition."

He feels that other factors must be involved, and that the insect decline has not been properly explained (his own belief is atmospheric pollution).

The most puzzling aspect of the affair remains the suddenness of the decline in the 1990s, when London's sparrow population fell off a cliff. What can have caused it? The introduction of lead-free petrol (containing other harmful chemicals)? The introduction of mobile phones? That does not explain why house sparrows are still numerous, for example, in New York and Washington.

You tell us. The prize remains to be claimed.

'Alarming decline' among London's house sparrows

20 July 2010

There has been an "alarming decline" in sparrows in London, the Royal Society for the Protection of Birds has said.

Its annual survey of the population of breeding birds has found a 68% drop in numbers compared with 15 years ago.

But it is unclear why this is the case, the society said, and a research project has been started.

Several species are on the increase, including robins, blue tits and magpies. The number of goldfinches has nearly trebled since 1995.

The number of house sparrows and song thrushes has declined more than in any other part of England, the report found.

This was "alarming", said the society's spokesman, Tim Webb.

"Their numbers are very low compared with historic levels and no-one knows why.

"Whatever is affecting them could be having an impact on our health and the wider environment," he added.

http://www.bbc.co.uk/news/uk-england-london-10695372
(Submitted by Liz R)