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P. Molinari and A. Molinari-Jobin
Material and methods
The study was conducted in the Jura Mountains, a secondary chain of limestone mountains
forming the north-western border of Switzerland with France. The most important prey species for
lynx in the Jura Mountains were roe deer Capreolus capreolus (69%) and chamois Rupicapra rupicapra
(22%; Jobin et al. 2000). Lynx usually fed for several days on an ungulate kill.
In December 1990, the adult female lynx “Aida” was caught in the Swiss Jura Mountains with
foot-snares installed at a fresh kill and fitted with a radio-collar (Breitenmoser et al. 1993). Until 31
December 1995, she was located on average every 2.8 days. During these 5 years she was re-captured
twice with foot-snares and four of her kittens were caught with the same system, which proved to be
very efficient. However, when Aida had to be caught the fourth time in order to change the radio-collar
in the winter of 1995/96, we were not able to catch her with the snares, as she became trap-wise. We
therefore had to change the capture technique: when we found a fresh kill made by her, we put up a
tent 4–8 m from the kill and waited inside with a blowpipe for Aida to come to feed. Aida was
re-captured with the blowpipe method on 16 February 1997.
The observer in the tent recorded the feeding succession and aggressive interactions of the
different lynx. To be able to observe the lynx after dusk we installed a small torch above the kill. The
signal from Aida’s radio-collar allowed us to estimate her distance to the kill even when we were not
able to see her. We continued our observations until family break-up with the same method even after
the capture of Aida.
Results
In May 1996, Aida gave birth to three kittens: two males and one female. From
September 1996 to March 1997 we observed Aida and two of her kittens at 12
different kills for 44 hours. One of the two kittens was clearly bigger than the other;
the third kitten presumably died before September. We started the observations on
14 September. Both kittens arrived at the same time. They spent a total of 85 min
on the kill, of which 45 min together, they did not seem to eat a lot of meat. From
the radio-signal we knew that Aida was nearby, but she only came to eat when her
kittens had apparently lost interest. The next day, both kittens arrived before Aida
and fed together at the kill. After a pause of two hours they restarted feeding, this
time, however, not together but alternating, with the smaller kitten feeding longer
than the bigger one. One hour later – when the kittens had finished feeding – Aida
arrived. While she fed, the bigger kitten played around with the kill. As soon as Aida
finished, both kittens restarted feeding before they all left. This detailed
description shows the typical feeding behaviour and rank order in which the lynx
fed (Table 1). On 26 September it was the bigger kitten which fed first, followed by
the smaller one. While the smaller one fed, the other kitten snarled and showed his
teeth. The smaller kitten retreated immediately. On 1 November we observed an
interaction between Aida and the bigger kitten: before it approached the kill Aida
was eating at, it rubbed against her, then they faced each other pushing their heads
together. It was only afterwards that it started to feed. We also observed how the
smaller kitten tried to feed while the bigger one was on the kill. However, the bigger
kitten no longer tolerated the smaller one nearby. The smaller kitten had only
access to the kill when the bigger one had finished feeding.