David Morley's 2018 analysis of how birds determine their geographical position
In about 1995 a pair of tiny birds, Spotted Flycatchers, started nesting in a rose trellis on the front of my house.
These little birds weighed less than 20 grams each and had flown from Southern Africa. They returned year after year only ceasing in about 2008. I thought that more than one generation must have been involved.
I started muttering about "How did they know the way" until my friends started ragging me, saying "Well, you're the scientist, you tell us !"
I started to study the matter, joining the Royal Institute of Navigation to get access to their extensive collection of published papers. I devoted about two months of evenings for several years to analysing what was known.
I had a bit of a head start because I had studied astronomy at University and knew the basics of spherical geometry and how people went about marine navigation.
I gradually managed to sort out the theories of avian navigation and I thought of a few more myself. As I went along, I tried to work out whether the various candidates could stand up to simple arithmetic and common sense. I thought about how you could replicate these theoretical ideas in arbitrarily advanced robotic models.
The results seemed to be very negative. None of the sugested methods stood up to reasonable arithmetical testing. It seemed not to be possible to mentally design a robotic strategy that could do what birds easily manage.
I pretty well hit the mental buffers in 2015 and it was only in 2017 and 2018 that I managed to make some progress and, eventually, to suggest what I call the "ALFIC" method.
Recent investigations of the concentration of tropospheric gases have shown that the ozone concentration depends on solar illumination and goes through pronounced peak in the middle of the day. This gives, in principle, a bird a measurement of how far east it is. It then becomes more plausible to think that a northing can be obtained from the earth's magnetic field.
ALFIC then means "Approximate Longitude from Inhaled Chemicals" Over land the chemical is ozone; over the sea some other chemical must be used, yet to be determined.
The ALFIC method will need more theoretical and experimental work and I have created the Facebook Group ALFIC to encourage engineers and other scientists to take an interest.
Normally, a new enabling idea in this field would be published in a peer reviewed ornithological journal. However, I have elected to write the matter out in a very short book which is now available.
At a time when most of the world's physics budget is being disposed on advanced quantum physics and on studying, for example, the nature of dark matter, the problems posed by 30 grams of bird probably seems quite trivial.
I believe in quantum mechanics because it works, but I have never really understood it. I try to restrict my thinking to more classical physics and to problem solving where data and the application of arithmetic may be thought to yield results.
I freely confess that our inability to understand the homing of pigeons and the navigational success of tiny birds has irritated me beyond reasonable measure.
"How Birds Navigate - The ALFIC System"
Author : D C W Morley
Publisher : Tushino Ltd
Paperback from Amazon 120 pp. Published 12 August 2018