geoscience.net logo
+ Resolve Article
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter

+ Translate
+ Subscribe to Site Feed
GeoScience Most Shared ContentMost Shared Content

Relative competitive ability does not change over time in blackbirds


, : Relative competitive ability does not change over time in blackbirds. Journal of Animal Ecology ch; 70(2): 218-227

1. Individual variation in feeding rate in the absence of competitors (absolute feeding rate) and decline in feeding rate in the presence of competitors (susceptibility to interference) are frequently used as measures of competitive ability or fitness in short-term foraging studies. They are also crucial parameters of individual-based population models that predict the distribution of animals across patches. There are, however, few data on whether absolute feeding rate and susceptibility to interference competition remain constant for individuals between years. 2. The hypothesis that absolute feeding rate and susceptibility to interference were similar between years was tested by observing 25 European blackbirds Turdus merula feeding in seminatural experimental patches, during January to March over a 2-4-year period 1995-98. Absolute feeding rate was measured as the feeding rates of solitary blackbirds. Susceptibility to interference was measured as the change in feeding rate of a focal bird when it fed in the presence of different numbers of competitors. 3. Individuals changed significantly in their feeding rate between years, but most individuals did not change in their feeding rate relative to others in the population. The absolute feeding rate of an individual was significantly positively correlated with its feeding rate in the subsequent year. 4. There was no significant variation in susceptibility to interference for individuals between years. Only two of 27 blackbirds showed a significant change in susceptibility to interference between years. 5. Relative absolute foraging rate and susceptibility to interference competition were reasonably similar between years in blackbirds. Relative fitness measures derived from short-term measures of foraging ability may therefore be valid over long periods. In ideal free models that incorporate individual competitive ability, rather than population averages, temporal changes in competitive ability can possibly be ignored.

US$19.90

DOI: 10.1111/j.1365-2656.2001.00486.x


Other references

Murin, A., 1975: Mitotic cycle duration in species with a multiple difference in nuclear DNA content. The duration of the mitotic cycle was compared in seedlings of Vicia faba and V. sativa and was found to be 27% longer in V. faba. V. faba was shown to have approximately eight times as much DNA per nucleus as V. sativa and it is concluded that th...

Weller C., 1977: Telemetry and continuous energy analysis of hypothalamic electro encephalogram changes in female cats during intromission by the male. Psychoneuroendocrinology: 287-301

Manuilova, E.S.; Lukash, L.L.; Shapiro, N.I., 1985: Mutagens and the tumor promoter. We studied the effect of 12-O-tetradecanoylphorbol-13-acetate (TPA) and saccharin on the frequency of induced mutations of resistance to 6-mercaptopurine and ouabain in Chinese hamster and mouse cells. UV-rays, bovine adenovirus-3 (BAV-3) and 5-br...

Kasorn, A.; Alcaide, P.; Jia, Y.; Subramanian, K.K.; Sarraj, B.; Li, Y.; Loison, F.; Hattori, H.; Silberstein, L.E.; Luscinskas, W.F.; Luo, H.R., 2009: Focal adhesion kinase regulates pathogen-killing capability and life span of neutrophils via mediating both adhesion-dependent and -independent cellular signals. Various neutrophil functions such as phagocytosis, superoxide production, and survival are regulated by integrin signaling. Despite the essential role of focal adhesion kinase (FAK) in mediating this signaling pathway, its exact function in neutro...

Aldous, E.W.; Fuller, C.M.; Mynn, J.K.; Alexander, D.J., 2004: A molecular epidemiological investigation of isolates of the variant avian paramyxovirus type 1 virus (PPMV-1) responsible for the 1978 to present panzootic in pigeons. A sequence of 375 nucleotides, which included the region encoding the cleavage activation site and signal peptide of the fusion protein gene, was determined for 178 isolates of the pigeon variant strain of Newcastle disease virus (PPMV-1). These w...

Feillet, N.; Girault, C.; Benhamou, D.; Testard, J.; Metayer, J.; Muir, J.F., 1993: One benign broncho-pulmonary lesion may hide another. The association of a granular cell tumour and an intraparenchymal pulmonary lymph node. The authors record the case of a patient who was under review for pulmonary tuberculosis in whom an Abrikossof granular cell tumour and a cyst were found which had developed from an intrapulmonary lymph node. These two entities are rare and their...

Back, C.A.; Grun, J.; Decker, C.; Suter, L.J.; Davis, J.; Landen, O.L.; Wallace, R.; Hsing, W.W.; Laming, J.M.; Feldman, U.; Miller, M.C.; Wuest, C., 2002: Efficient multi-keV underdense laser-produced plasma radiators. Novel, efficient x-ray sources have been created by supersonically heating a large volume of Xe gas. A laser-induced bleaching wave quickly ionizes the high- Z gas, and the resulting plasma emits x rays. This method significantly improves the prod...

Thoria, L.; Ahmad, N., 1943: The analysis, grading and utilization of Indian linters. Approximately 40 samples of cotton linters representing various types of seed were analysed and graded by three different methods.

Bergh, A.; Damber, J.E.; Lieu, L.; Widmark, A., 1992: Does follicle-stimulating hormone or pregnant mare serum gonadotrophin influence testicular blood flow in rats?. Treatment of adult rats with 25 iu follicle-stimulating hormone (FSH) did not influence testicular blood flow, serum testosterone, vasomotion or intravascular leucocyte concentration at 6, 12 and 24 h after treatment. Treatment of adult rats with...

Krause, K.H.; Rentrop, U.; Mehregan, U., 1979: Cerebral manifestations in angioneurotic edema. Two patients with hereditary angioneurotic edema are described. A female patient, born in 1929, showed an infarction in the area of the right posterior cerebral artery, verified by computer tomography. The son of this patient, aged 20 years, suffe...