MIGRATIONAL NAVIGATION SITE - LONGITUDE

This web site, together with  www.3aaa3.info, is concerned with the ways in which migrating birds navigate to their destination. This site mostly deals with the longitude problem and 3aaa3.info mostly deals with latitude and general matters. If you haven't already done so, I recommend that you read through the material on 3aaa3.info

I think nearly everyone who has interested themselves in how migrating birds navigate has run against the blank wall of how birds can know their East-West position. I considered this matter every January and February from Y2001 until Y2005. Every year I simply gave up in frustration, my brain tied in a knot. Every year in April two Spotted Flycatchers came to my house from Africa. "Think harder !" their presence seemed to be saying.

In the end I decided that the birds could not know their longitude. I thought they must navigate by latitude and some other coordinate.

Although I could not find a plausible candidate for another coordinate, I started looking at the problem rather differently.

I was in possession of a reasonable number of my own failed calculations and I started looking at them in the light of "second coordinate" rather than "longitude".

Eventually I stumbled on the idea which is explained in the paper on "Line Following" which you can download in English      here, in German        here and in Russian       here.

Essentially the idea is this. If a bird can measure time over 24 hours to plus or minus a few minutes, then it can follow certain geographical lines quite accurately. It can do this even if it stops and rests for a few days.

The necessary two co-ordinates are the line itself and the latitude which the bird can determine by some means related to the material on   www.3aaa3.info

I have included a note "Results A" which you can download  here. This is a summary of the trial and error calculations I made for particular birds.

I have also worked out the possibilities for the Bar Tailed Godwit "E7" and put them in a separate note which you can download   here.

Although the idea seems simple, there is a good deal of arithmetic attached to the development and I have included on this site a calculator to help interested readers.

First download instructions   here on how to download the calculator. This is not quite straightforward for an EXCEL workbook. Follow the intructions closely.

Then download my   Notes on how to use the calculator. Using other people's computer tools is often frustrating because the author often forgets to write down things he thinks are obvious. (Think of any Microsoft Manual !)

Finally download the   calculator

The author of the content is D.C.W. Morley

Latest revision 30 January 2011                                                            This site is owned by Tushino Ltd