Spacing of Adult and Subadult Male Common Capercaillie during the Breeding Season

Abstract

AI•STR^CT.-The spacing behavior of 58 male Common Capercaillie (Tetrao urogaIlus) was studied at Varaldskogen in southeast Norway during 1979-1985. Birds captured at leks were equipped with radio-transmitters, and their movements were monitored throughout the year. During spring, males 4 yr old and older occupied exclusive day territories of 10.2-66.0 ha that extended radially from a center at the lek. Adult cocks used the same lek and the same territory during successive years. Among marked birds, the youngest bred at 4 yr. No difference was found in territory size between breeding and nonbreeding adult males. Territories of 3-yr-olds (60.8 ñ 10.4 ha) were larger than those of older males (26.3-5.0 ha) and were located farther from the lek. All territories were within a 1.2-km radius of the lek center and were maintained from early April to the end of May. Yearlings and 2-yr-old males were nonterritorial. They moved irregularly among different, neighboring leks, settling near one lek at the end of their second spring season. When associated with one lek, their home ranges were 3-6 times larger than and overlapped peripherally the territories of resident adults. Established subadult and adult males did not change territories when vacancies were created by deaths of older birds, and successful matings were not dependent on occupying a particular territory.

Noninvasive genetic sampling allows estimation of capercaillie numbers and population structure in the Bohemian Forest

“…10, Rösner et al unpublished), which might lead to higher relatedness among males as relatives establish at leks in the vicinity of their natal areas (see Regnaut et al 2006;Alda et al 2013). Moreover, adult males show high lek site fidelity (Wegge and Larsen 1987) and mating success is highly skewed, with only one or very few successfully mating males (Mäki-Petäys et al 2007;Storch 1997). As a consequence, reproducing males are often relatives, which may lead to kinship at lek sites Regnaut et al 2006).…”

Kin groups in closely spaced capercaillie leks

“…Hence, their mating leks were not known. Males were classified into three age groups based on beak depth measurements (Moss et al 1979), using the age class intervals adopted by Wegge and Larsen (1987). For our analysis we considered males more than 2 years old as adults.…”

“…In undisturbed, contiguous habitat, leks are typically spaced 2-3 km apart (Wegge and Rolstad 1986). Adult males return to the same lek in successive springs until death, whereas young birds (yearlings and 2-year-old males) may visit several leks during a season (Wegge and Larsen 1987). Large leks in boreal ecosystems often consist of 20-30 males at one lek (Borchtchevski 1993;Potapov and Flint 1989), whereas, in isolated populations in Central Europe (e.g.…”

Spacing of leks in relation to female home ranges, habitat requirements and male attractiveness in the great snipe (Gallinago media)

“…However, there may be a potential drawback on this study in relation to the hotspot and female preference hypotheses as. capercaillie are exploded breeders (leks were males are so spaced they cannot see each other, sensu Gilliard 1969), and thus may use at least parts of their territories for purposes other than solely attracting mates (Wegge and Larsen 1987). If feeding requirements determine the size and spacing of capercaillie territories, the assumptions of the hypotheses being tested would be undermined.…”