Its been a while since my last post, but hopefully with the end of year slow down, I can find more time again to fish out some interesting birding information. 

I remember asking my dad as a kid why all the birds sat on the telephone wires every day at dusk.  If I remember correctly his answer was in the line of: “They are meeting up to get ready to fly back home."

Later on in life this has opened some more questions. The first one was, but who says that this is not home, and they are now flying to go visit? I now believe that home is here, our summer is longer and thus they stay longer here than in the northern hemisphere. But this question will remain debatable.

The second question was that each night it would be the same group of birds, one night maybe a few less and the next a few more, and then one day thay are all gone. So obviously they did not wait to meet up with others.

So why do they sit on the wires facing the sun each day? It seems one of those unanswerable questions.

 If it bothers you as well not knowing what the real answer is, don’t feel bad. Up until recently, scientists haven't had any decent theories either. But what's emerging from the latest studies may finally provide a real answer.For years, evidence has suggested that migratory birds use a combination of cues from the earth's magnetic field, patterns of stars, and polarized sunlight to guide them on their twice-annual north-south journeys. What researchers haven't been unable to figure out is exactly how all these cues work together to keep the birds on-course over weeks of travel and thousands of kilometres.

Recently researchers from the U.S. and Germany captured songbirds during their migration north and kept them enclosed where they were unable to see the sun while exposing them to altered magnetic fields. When they were released after sunset to continue their evening migration, the birds took off in the wrong direction. The direction they headed corresponded to the direction they should have gone if the erroneous magnetic field had been correct.

Tracking the birds across parts of the US for several nights, the researchers discovered that the next evening, after resting and being able to observe the sunset, the birds flew off in the correct direction, and continued their migration uneventfully.

Further scientific studies seem to confirm that birds regularly use their sunset observations to recalibrate their internal GPS systems. Yet, how the literal "bird brain" is able to process such complex calculations so accurately is still unknown.

Several new studies are leaning toward the existence of chemical compounds that are reactive to light and magnetic fields. Peter Hore of the University of Oxford believes cryptochromes - rare proteins involved in animals' biological clocks – may be the secret.Hore's theory is that in the presence of the blue light predominant at dusk, cryptochromes generate a specific chemical output in a quantity regulated by the magnetic field. Based on the concentration of these chemical markers, other molecules interacting with them inform birds of their latitude. To make the whole process work, however, the birds have to expose their retinas to the sky at sunset.

So now, when our kids ask us the same question we can now truthfully tell them it is to reset their Garmin’s.

Not only is it true, it even sounds better.

Cheers