Observations on territoriality of blackcocks at a traditional lek in the high Rhoen mountains of Hesse (Germany)

The lek is situated in the NW part of the Nature Reserve , ®Rotes Moor¯ (314 ha, established 1979), at approx. 820 ru NN, in the middle of the long ridge between the top of Wasserkuppe (954 m, highest point of Hesse and the Rhoen area) and the top of Heidelstein (926 m) in the Bavarian Nature Reserve, ®Lange Rhoen¯. The lek has been known at least since 1945, and is the central one of at the most 8 leks which until then had been frequented by a varying number of Blackcocks in different years. The size of this arena is obviously determined by clear views as well as safety from predators in relation to the height and structure of the local vegetation. This vegetation consists of meadows and pastures (dry to wet, dominated by Nardus, Trisetum and Trollius) in both, extensively used and unused stages. This lek is typical of leks throughout the Rhoen Mountains. Between 1960 and 1984 this arena was much reduced in size owing to spruce afforestation. In the years from 1960 to 1970 a minimum of 21 ha of suitable space had to suffice for a number of up to 18 males. Since 1975 the population of black grouse in this area has decreased to its lowest number ever, and from then on this arena was visited sporadically by single males only. Habitat management, especially clear cutting of spruce stands (in total 120 ha) improved the Nature Reserve in general and lekking conditions at this lek in particular, with an increase in the suitable space to approx. 55 ha by 1985. Nevertheless, it took until 1989 before one single male came to display there regularly again. The male was identifiable by a characteristic feature: three black spots in the right half of undertail coverts, which gave him the name, ®three-spots-right¯. He returned every year until 1994. His territorial activities have been recorded since 1990. In autumn 1994 the male did not turn up. A subsequent scrutiny of his home range which had included nearly all suitable areas of the Nature Reserve, proved unsuccessful (only one Greyhen was found). ®three-spots-right¯ who had reached an age of about 7 years, was probably killed by a predator. Since 1990 one or two yearling males visited the arena every year, both in spring (at the earliest 28 April, at the latest 13 June) and in autumn in the years 1991 (14 September) and 1992 (28 August and 19 September). They were probably all sons of his. He gave them no chance to establish their own territories there. Despite lack of competition ever since, the previous alpha male has still not been succeeded. ®three-spots-right¯ was a typical alpha male. He ruled supreme for 5 years over a relatively large arena and performed 100 / of copulate (the earliest 28 April, the latest 12 May) with up to 3 females who visited the arena in all the years listed, in both spring between 19 April and 15 June and in autumn between 9 November.