Search results for "black grouse"

Paternity, copulation disturbance and female choice in lekking black grouse

1996

Female copulation behaviour in the black grouse, Tetrao tetrix, was studied by detailed observations of individually marked birds together with DNA fingerprinting analyses for paternity assessment. For each breeding occasion females typically mated only once with one male, and did not mate outside the lek arena. They re-mated with the same or another male usually only if the initial copulation was disturbed and was probably unsuccessful in sperm transfer. The willingness of females to copulate only once with one male suggests that multiple mating with several males incurs a cost that more than outweighs any possible fertility or sperm competition benefits. Attempts by neighbouring males to …

Low levels of relatedness on black grouse leks despite male philopatry

2008

In lekking species, males cluster on specific areas for display (the leks) and females generally prefer to copulate with males on large aggregations. The maintenance of leks in which only a few males reproduce might be explained if subordinate males gain indirect fitness benefits. By joining a lek on which relatives are displaying, subordinates might attract more females to the lek thereby increasing the mating opportunities of their kin. In black grouse, a genetic structure among leks has previously been found suggesting that relatives could display together. Using 11 microsatellite loci, we extended this result by testing for the presence of kin structures in nine black grouse leks (101 m…

Testosterone and male mating success on the black grouse leks

1996

On black grouse (Tetrao tetrix) leks females prefer dominant, viable males that have managed to acquire relatively central territories. The immunocompetence hypothesis predicts that, because high levels of testosterone are costly to the immune system, male sexual traits that are controlled by testosterone are likely to serve as reliable indicators of male health. Indeed, testosterone concentrations of black grouse males were highly variable, and strongly correlated with male mating success. This is related to the fact that males with high testosterone levels had most central territories. However, the association of testostestorone level with male mating success was not solely related to cen…

Short- and long-term population dynamical consequences of asymmetric climate change in black grouse

2006

Temporal asymmetry in patterns of regional climate change may jeopardize the match between the proximate and ultimate cues of the timing of breeding. The consequences on short- and long-term population dynamics and trends as well as the underlying mechanisms are, however, often unknown. Using long-term data from Finland, we demonstrate that black grouse ( Tetrao tetrix ) have responded to spring warming by advancing both egg-laying and hatching. However, early summer (the time of hatching) has not advanced, and chicks have to face colder post-hatching conditions. Demonstrating that these conditions are critical to post-hatching survival, we show that chicks are increasingly suffering highe…

Evolution of black grouse leks: female preferences benefit males in larger leks

1992

Mate sampling behaviour of black grouse females (Tetrao tetrix)

1995

We studied female mate sampling behaviour in lekking black grouse (Tetrao tetrix). Females mainly visited males occupying territories in the centre of the lek with relatively large territories. They were also more likely to visit males that had high attendance. The same factors were also correlated with male mating success. A multiple regression model including these factors explained more of the variance in female visits per male (53%) than in mating success (33%). The pattern of female sampling conformed with a pool comparison (best-of-n) tactic. Such a tactic is expected if the costs of sampling are low. Females of high body mass visited more males than lighter females, however, which in…

Lek centre attracts black grouse females

1994

In several lek mating systems, centrally located males enjoy higher mating success than peripheral males. The mechanism behind this pattern, however, has been controversial and a rigorous test of the different alternatives is missing. Here we report that in black grouse Tetrao tetrix , a lekking bird species, central males achieved many more copulations than males in the periphery. Generally, central territories were smaller than peripheral ones, and males were thus more clumped in the centre. A choice experiment in an aviary provided experimental support for females being attracted to densely clustered males, so that males in larger clusters have higher expected average mating success. Thu…

Why Do Black Grouse Males Perform on Lek Sites outside the Breeding Season?

1999

Studies of sexual selection have focused mainly on explanations of how male characteristics influence mating success during the breeding season. By contrast, few studies have investigated how behaviours prior to the breeding season influence mate choice d

Combs and sexual selection in black grouse (Tetrao tetrix)

2000

We studied supra-orbital combs in lekking black grouse (Telrao tetrix) in relation to sexual selection at five leks in Finland 1991-1998 and four leks in Sweden 1992-1995. Comb size was estimated in two ways: by observing its natural size in the field at

The effects of parasites on male ornaments and female choice in the lek-breeding black grouse (Tetrao tetrix)

1992

We describe the results of two studies of parasitic infection in the black grouse (Tetrao tetrix). The first deals with our own observations of lekking black grouse in which the parasite levels of two blood parasites, the protozoan Leucocytozoon lovati and microfilaria, probably produced by a nematode worm Splendidofilaria tuvensis, were scored. We also obtained measures of age, survival, number of copulations, body mass and length of the ornamental tail feathers (the lyre) of the lekking males. The second study analysed the data from Lund (1954) which involved eight gut parasites obtained from birds which were killed. In the first study we found higher levels of infection of Leucocytozoon …