Several previous studies have reported that birds decrease the frequency parameters of their vocalizations in a territorial interaction (black-capped chickadees, P. atricapillus; Hill and Lein 1987; Otter et al. 2002; Montezuma Oropendolas, Psarocolius montezuma, Price et al. 2006; scops owls, Otus scops, Hardouin et al. 2007; African black coucals, C. grillii, Geberzahn et al. 2009, 2010).
The Spearman's rho calculation highlighted a significant correlation between the ACI values and the number of bird vocalizations, while the frequency bin occurrence and acoustic intensity were weaker correlated to bird singing activity because of the inclusion of all of the other geo/anthro-phonies composing the soundscape.
In the physical exercise, students calculate the reproductive success of the birds plastic chips represent the alleles of each bird, and after each generation the birds reproduce based on the frequency of these alleles in a bag, thus simulating recombination.
In birds, mammals, and insects, the frequency distribution of range sizes tends to be unimodal and right-skewed (i.e., most species have relatively restricted ranges)[6], [7].
Regarding attitudes about hunting influenza-infected birds, our results revealed that the frequency of First Nations hunters who would cease harvesting birds increased as AIV was detected in more nearby geographic areas.
For each bird, we also noted the frequency of copulations and the aggressive interactions they were involved in.
Furthermore, because we used a representative subset of California terrestrial breeding birds, it is likely that we underestimated the frequency of no-analog bird communities that would be apparent if greater ecological complexity were considered.
Experts say the frequency of bird strikes depends partly on time of day and species.
But Coward, whose organisation represents more than 90% of egg producers in Queensland, said it was not the number of hens that was important but the environmental conditions of the farm and the frequency of bird rotation.
A: Only a few studies have examined the frequency of bird collisions for significant numbers of wind turbines -- one in Denmark and two in California.
