Blue House Sparrow
© Richard Shears/Daily Mail
A blue house sparrow has appeared in Sydney, out of nowhere. Experts are convinced the colour is genuine, but baffled as to the cause.

Richard Shears reports seeing a blue house sparrow in April this year (Passer domesticus) in his garden in Sydney, Australia. At first he thought he was seeing things, but he made no mistake.

On the first day he was unable to photograph it, but it returned again 1 day later and managed to take a few photographs.

The bird was flying with a flock of normally-coloured house sparrows, which are light and dark brown.

Shears began doing some research on the web, looking for references to blue sparrows. After being unable to find anything relevant, he started asking questions with ornithologists and other experts.

Ornithologist Mirek Lanparski said "This is amazing. I've never seen anything like it. I thought at first that perhaps someone had dyed it, but looking closely you can see that's not the case, and who would want to catch a sparrow, dye it blue and then let it go again? In any case, those are natural colours and that's very, very peculiar."

New South Wales Field Ornithologists Club official Mr Allan Ible said it was "totally new" to him.

Another member, and former National Parks officer Mr Allan Morris said "This is quite strange. I've seen all kinds of unusual birds, even albino ones, but I've never heard of a blue sparrow."

Some birds do have genes which encode for blue colouration, but not the house sparrow.

(Reader tip: stay tuned ... Where Light Meets Dark has received a report from a reader - including photographs - of other blue birds in New South Wales. They are a different species, leading me to believe the cause is not genetic but rather, diet-related. Canaries are well known for turning orange after being fed carrots, and flamingoes turn pink depending on the shrimp they eat. I question whether there has been any change to insecticides or pesticides used on NSW crops in the past 3 months? What else could NSW birds be eating that is blue? Send me your ideas!

Digging a little further, many webpages suggest that blue pigment does not exist in bird feathers. If this colouration is caused by diet as I suspect, then I think that claim will no longer hold true!

Finally - one last theory... algae. Polar bears and sloths are known to turn green due to algae living within their hair - could our unusual weather patterns of drought and recent rains have stirred up some form of algae which has begun inhabiting bird feathers?

I can't wait to plot these bird locations on a map...

Photos to come, pending permission...)

Source: Daily Mail