Eagle72 - Feeding

History

Eagle feeding has been going on for a long time in Sweden. Already in the winter time 1955 the author and ornithologist Bengt Berg fed eagles with dead red deer on his manor Eriksberg outside the town Karlshamn in the very south of Sweden. The feeding went on until 1993. Bengt Berg was for certain, because of his political position, a very controversial person but it is not possible to deny he has done a great work for Swedish  nature conservation, especially for the eagles. It was thanks to him that the golden eagle and the white tailed eagle, in 1924, were protected by law.

Another eagle pioneer was a very good friend of Bengt Berg, count Hans Wachtmeister on Tomtö outside Ronneby also in the very south of Sweden. At visit there Bengt Berg made a classic comment to his friend "Brother shall you feed the king of the air with dead pigs". The day after a car arrived to Tomtö from Eriksberg with several dead red deer.   

His view of feeding eagles appears of a quotation from his book "Eagles" written in 1960

"If we only took the step to, at a dozen protected places in the south of Sweden, yearly give up some of the many natural dead animals to the winter eagles in our country, the damage they make on our stock of game would decrease to almost nothing.
It would be as praiseworthy as good game wardens feeding of such game  they later will hunt and eat and a kind action for nature conservation and associations for
hunting  to do in cooperation. It is easy as Columbi egg and probably just what is needed to ensure the continuance of our treated eagle population"     

All feeding is, since 1997, regulated in law. The law is an application to the EU-rules and means that:

• feeding with meat from domestic cattle must be done with vet inspected offal from controlled slaughterhouses.

• all feeding, even with vet inspected offal, need permission from the regional veterinarian.

Methodology

The feeding place is mostly a lonely place and the exact position is kept within the group. We are afraid that the eagles will be disturbed if the place become to well known. However there are some feeding places were people in common can come and  look for eagles without any risk for disturbance. Such a place is the well known Hornborgasjön.

The feeding season starts in the mid or end of November and last to the mid or end of March. The length of the period depends on where in the country the place is.
The food is vet inspected meat from slaughterhouses and we refill the feeding place 3 times a week with about 40 kilo each time. To not disturb the eagles we always do the work when it is dark

Winter feeding gives a unique opportunity to study the colure-ring marked eagles, both golden eagles and white tailed eagles. To do that most of the places have a small cabin to observe the eagles  from a close distance and hopefully read their ring numbers. Nowadays we give priority to such places that have an observation cabin.

From the cabin we follow the eagles during the whole winter. We try to separate the different individuals from each other and estimate the total number of eagles. That is not easy and myself always try to estimate the minimum numbers of eagles over a season by following criteria:

• ring marking
• age
• special signs such as a certain look or behaviour that can be separated during a whole season.

There are three common eagle counting's every season when all feeding places all over Sweden count their eagles at the same time. They are normally performed the second weekend in December and the first weekend in January and February.

During the last season 2009-10 there were 13 feeding places running and the amount of food needed was about 33 tons or 2 533 kilo per place.
The number of visits to refill food were 529 or an average of 41 visits per place.
In order to read coloured rings, observation of the eagles from a shelter very close to the feeding place has been a main issue and 11 places have reported a total number of 3 038 observation hours. This is a mean value of 276 hours or about 35 days per feeding place (average for the 11 places).
The number of observed golden eagles were 339. It is an average of  26.1 eagles per feeding place but the difference between the places is large. Two places has reported as much as 105 and 71 different golden eagles, respectively.
The number of observed white tailed eagles were 296. It is an average of 22.8 eagles per place. Also for the white tailed eagles  there is a large difference between places.  Two places has reported 95 and 70 different eagles, respectively.
Note that some of the eagles can have been observed on more than one feeding place. Calculations shows that about 91 % of the reported golden eagles and 84 % of the white-tailed eagles are different individuals.
The number of observed eagles the last five years can be seen in table 1 and in table 2 the eagles age distribution for the last season is reported.

As normal, three common eagle counting's were done during the season.
The first counting was held the 12-13th of December and 14 places were checked. A total number of 68 golden eagles (14 adult, 49 subadult, 5 juvenil) and 134 white-tailed eagles (68 adult, 52 subadult, 14 juvenil) were observed. 18 of the golden eagles and 54 of the white-taled eagles were ring marked.
The second counting was held the 9-10th of January and 14 places were checked. A total number of 49 golden eagles (11 adult, 30 subadult, 8 juvenil) and 81 white-tailed eagles (47 adult, 22 subadult, 12 juvenil) were observed. 9 of the golden eagles and 22 of the white-taled eagles were ring marked. Very cold temperature during the weekend caused the low figures compared to previous years.
The third counting was held the 6-7th of February and 13 places were checked. A total number of 70 golden eagles (18 adult, 44 subadult, 8 juvenil) and 123 white-tailed eagles (79 adult, 30 subadult, 10 juvenil, 4 unknown) were observed. 16 of the golden eagles and 57 of the white-taled eagles were ring marked.
A summary of the results from the last 5 years counting can be seen in table 3.