Pierre Dordin (Harnes, FR) studied the influence of location, wind and mass on the results - Part III

In the third and final part of this article, Pierre Dordin draws some conclusions from his study.


The commission noticed that the pigeons had followed the coastline, probably from their release site until St. Nazaire. After that they had likely set course to Le Havre to follow the coastline again.

They did not try to figure out why the pigeons followed a westward route. The wind cannot have influenced the pigeons a lot: there was no wind in the morning and during the day there was a wind speed of only one to three metres per second.

The only goal of this experiment was to investigate the influence of a flight line that is longer than the theoretical flight line (in a straight line) on the results of a race.

The question is how many kilometres the pigeons have covered whose loft is located near the theoretical flight line of Morcenx-Lille and on the east side of it.

Let's have a look at figure 2:

Let’s assume that the best pigeons from the other districts have been flying as fast as the winners from Pontorson. The results in the first district (Nord and Pas de Calais) show that the fastest pigeon from there has been flying for about 705 minutes that day. The average speed of all pigeons equals that of the first national prize winner from Pontorson (1395 m/min), which means that the pigeon from the northern district (which is far away from the release site) would have covered a distance of 981 km (705 minutes x 1395m). However, the official distance from the release site to that district is only 805 km. This is a difference of no less than 180 km or 22%!

The first pigeon from district Paris needed 607 minutes to arrive home. This means he covered a distance of 755 km (607 minutes x 1395 m), instead of the official distance of 587 km. This is a difference of 170 km or 25%.

We can also prove that the pigeons from Limoges, eastwards of the theoretical flight line, have covered a total distance of 360 km instead of the official 260 km. This means they have covered an additional 100 km!

The location plays a key role at regional and local level as well. We will try to illustrate this with the previous examples.

Let’s have a look at figure 3 first.

Two lofts (A and B) are perfectly in line along the flight line; loft B is 10 km further than loft A. Two pigeons on their way home fly together until they simultaneously arrive at loft A, where one of the pigeons enters its loft. The other pigeon belongs to loft B and has to cover an additional 10 km.

How much time is counted for the additional distance?

That depends on the district of the two lofts. Let’s draw a comparison between the districts of Paris (620km) and Rouen (650 km): they are a good comparison when it comes to distance and the number of basketed pigeons. The fastest pigeon from Paris had a speed of 1090 metres in 60 seconds or 1,000 metres in 55 seconds. The fastest pigeon from the district of Rouen did 1,395 metres in 60 seconds or 1,000 metres in 43 seconds. How does a difference of 12 seconds influence the results? The answer to this question makes clear that a deviation from the theoretical flight line has an enormous influence, even for lofts that are very close to each other! If the lofts A and B are both in the district of Paris the pigeon of loft B (which is 10km further from the release site) will be given a time advantage of 9 minutes and 10 seconds for the additional 10 km (10 x 55 sec).

If the two lofts were in the district of Rouen, pigeon B would gain a time advantage of only 7 minutes and 10 seconds (10 x 43 sec).
This basically means that the pigeon from Rouen has an advantage of two minutes over the pigeon from Paris, which we will call advantage X.

Again we have two pigeons (A and B) that fly home together; the situation is the same as in our previous example. However, pigeon B is smarter and decides not to fly over the loft of pigeon A. At a certain point S, 15 km away from loft A, pigeon B takes a different route. What is the outcome? When pigeon A arrives home it has covered 15 km from point S. At that moment pigeon B has already reached point B. However, the distance from P to B is a lot smaller than the distance from A to B. The result is that pigeon B is believed to have covered an additional distance of 10 km (and gets an equal time advantage) but he actually only covered three extra kilometres. This is an advantage of 7km, which we call Y.

Advantage X is the result of a difference between the actual speed that the pigeon reached and the speed calculated by an erroneous system: Own Speed (OS)! The difference increases even more as the actual distance becomes bigger than the distance according to the OS system.
Advantage Y comes from the fact that the pigeon is believed to have covered a few extra kilometres (so the bird wins a few places in the results) than it has covered in reality. The pigeon benefits even more as the angle of the different route increases. This advantage can count up to 100% with strong crosswinds!


The advantages and disadvantages of significant changes in the flight line (whether or not caused by a crosswind) are enormous. Depending on whether the pigeons take an eastward or westward route (instead of a straight line) pigeon fanciers will have a big advantage or disadvantage. In many cases these (dis)advantages prove decisive in the race. Wind, mass and several other known and unknown factors will cause pigeons to follow a different flight line. The advantage a fancier has from this different route ranges from 0 to 100%.

Two lofts C and D are at the same distance from the release site; C is located 10 km to the east compared to D. When using the system of Own Speed the pigeon of loft C will have an advantage of 10 km. If the pigeon has a velocity of 1,000 meter/min it will have a 10 minute time advantage in the results!


The fact that pigeons do not follow the theoretical (straight) flight line but rather fly leftwards or rightwards will be advantageous to the regions that are located along this alternative route. Pigeons that have to cover a longer distance will benefit as well (under the same circumstances), albeit to a much lesser extent. The influence of the location is astonishing. On the other hand a loss in speed caused by fatigue in races with a velocity of 1,200 to 1,400 m/min is probably insignificant. The region that is on the other side of the actual flight line (compared to the theoretical flight line) will have a significant disadvantage.

Food for thought

Dordin and his assistants came to the conclusion that there is a disadvantage for the pigeons that have to cover a shorter distance. This was of course something the West Flemish national long distance fanciers loved to hear. In the Flemish pigeon magazine, De Duif, there was an argument between a fancier from (Belgium) Limburg and a West Flemish fancier. The latter used the findings of this study to prove his point.

The fancier from Limburg argued that the study of Dordin could only be useful in Belgium and the Netherlands when they can also determine the influence of a crosswind and other factors on the flight line of the pigeons! We tend to agree with him. When we take into account the shortest and the longest distances we should note that the situation in France is totally different: Bordeaux is 90km away from the release site in Morcenx; Lille is no less than 800 km away! So it is difficult to make a comparison with Belgium, where the difference between the shortest and the longest distance is much smaller.

In the light of this study of the official French Commission Sportive Nationale, I would like to point out the following: in the race on 8 July 1850 the wind cannot have played a significant role. The alternative flight route that the pigeons followed and the resulting advantage for the regions on the west side of the theoretical flight line (which is why Pontorson and St. Nazaire won nearly all prizes) was caused by something else! Some fanciers assume that the main reason for this alternative flight route is the fact that pigeons from Bordeaux, Morcenx, Dax, St. Jcan de Luz, St. Vincent, San Sebastian etc. focus on the coastline to orientate. There might be some truth in it and we think it is time to investigate this matter.

This is especially the case for France. I think we can agree that the national races are not at all a fair competition under these circumstances and with this sytem. The same applies to Belgium and The Netherlands. It is a happy coincidence that the wind in the Low countries usually blows from the south west (seven days out of ten). A south-west wind is not a crosswind but rather a pure tailwind. This tailwind usually results in a velocity of 1,200 m/min and more; as a result of which speed loss caused by fatigue is usually kept to a minimum.

If we would release the pigeons north eastwards the pigeons that have to cover the longest distance would simply not be able to win a single prize! That is why the idea of the fancier from Limburg, to fly from Hamburg, makes no sense to the West Flemish fancier. He might as well have proposed to race from Korea.

Click here for part I of this article. 

Click here for part II of this article.


Is in grote lijnen alzo mijn bevindingen.

Zal je nog meer vertellen:
Test kan heel eenvoudig gedaan worden op "een enkele vlucht".
Waarin ik je zou kunnen laten zien waarom die duiven die Nw beweging maakte naar de kust streek.

Hiervoor zou ik de Nationale vlucht vanuit Limoges willen gebruiken.
In 85% van alle vluchten uit Limoges is dat een typische vlucht voor de beide vlaanderens quasie de 50 eerste prijzen
(-enkelen duiven uitzonderingen)
akkoord ? Zo ja...
los die duiven dan eens in limoges om 12H 's middags in plaats van om 7h of 8h. ondanks het mooie weer.
Ik voorspel je nu al dat het totaal anders gaat zijn.

Gelieve dit gewoon wetenschappelijk op tenemen ? als onderzoek naar wat de duiven doen..
En niet als de Vlaanders de duvel aandoen.
Gewoon Limoges 01-06-2013 lossen om 12H 's middags! Smile
Om theoriën te bewijzen heb je nu eenmaal een proefvlucht nodig.

De oplossing van het raadsel is inversie. Er wordt gesproken van perfecte omstandigheden en bij een dergelijk vroege lossing heb je bij dergelijke weersomstandigheden altijd het probleem inversie. Ik zal proberen dat uit te leggen.

Normale omstandigheden zonder inversie: de zon komt op in het oosten en haar stralen komen onder een bepaalde hoek op aarde terecht. Deze gebruiken duiven om zich te oriënteren en kiezen aan de hand hiervan hun vertrekrichting naar het thuishok.

Nu met inversie. Eerst een uitleg wat inversie is. Inversie zijn vochtige lagen in de lucht. Deze lagen werken als lenzen en breken de zonnestralen extra; deze komen dus meer westelijker op aarde terecht. Hoe hoger de inversie hoe westelijker. Dus duiven vermoeden hun thuishok meer westelijker en kiezen voor een westelijker route naar huis. Dat is de verklaring voor de overheersing in de uitslag op deze vlucht.

Hier kunt u een en ander er eens op nalezen:


The Saint,kan inversie dan ook gemeten worden? Als dat zo is zou het misschien nuttig zijn om dat dit jaar al bij de lossingsgegevens te zetten en dat eens goed op te volgen.

Jazeker. Indien de lossingsverantwoordelijken dit aan het weerbureau vragen die de gegevens verstrekt is dit 100% mogelijk. In Nederland wordt hier al meer dan 10 jaar mee rekening gehouden en ook vermeld op de Teletekst lossingspagina die iedere liefhebber kan raadplegen. Er staat vermeld hoe sterk de inversie is en wanneer deze precies is opgelost. Daarna kan er worden gelost met 100% kans op een eerlijke uitslag. Indien u meer wilt weten vraag dat gerust.