Growth of the Osprey Pandion haliaetus
population
in the Orleans Forest 1984 - 2003
data collected by "les Naturalistes
Orleanais" 1985 - 1994, and by Rolf Wahl from 1995 unwards
graphs made by Ruud Kampf
no use without permission!
(E-mail: rowahl@rekel.nl)
2003 |
occupied |
succesful |
nr of young |
nr of young per nest |
nr of young per succesful nest |
Orleans forest |
14 |
11 |
27 |
1.93 |
2.45 |
Chambord |
4 |
2 |
5 |
1.25 |
2.5 |
grand total |
18 |
13 |
32 |
|
|
Plus one nest in Isle de France, near Paris
|
|
|
After initially a long
period with only one succesful pair the population keeps growing |
|
|
|
From 1985 to 2002 a total
number of 140 young has fledged. |
|
|
|
This fit of the number of occupied nests
shows that the population still grows with an exponential rate, partially because of the
influx of birds from the German population. The
equation of the fitted model is:
Year_nests = exp(-328.304 + 0.165202*year)
Since the P-value in the ANOVA table is less than 0.01, there is a statistically
significant relationship at a 99% confidence level.
|
|
|
|
The breeding success of
the Orleans "colony" is with 2.27 young per succesfull nest since 1989 very good
(2.07 per breeding pair). The new "colony"in the Chambord forest gives
comparable results. |
|
|
|
|
The spacial development of the population in the
Orleans forest from 1990
With many thanks to Rolf Wahl, specialist on Ospreys
in the Orleans Forest for the hospitality and company
When you find any information on Ospreys with colored
rings in France, please contact Rolf Wahl
(E-mail:rowahl@rekel.nl)
back to the Osprey index page
of Ruud Kampf
Home page Ruud en Kitty
Kampf
Email: ruud@rekel.nl
