In this study territory densities of field-breeding farmland birds were compared on pairwise-selected organic and conventional arable farms for two years.
The movements of the 12 displaced birds were compared to the migration of eight non-displaced common cuckoos tagged in Denmark and southern Sweden (see for a detailed description of this migration).
Samples from 3 infected birds were compared to 3 uninfected controls and normalized against eukaryotic 18 s rRNA expression.
The effects of lead and chelation therapy on toxicological, biochemical, and oxidative stress parameters were evaluated and the results obtained from poisoned birds were compared with those from non-exposed vultures.
When 2 3 complete N-protein gene sequences (1,143 nt) originating from any bird were compared, nucleotide sequence identity ranged from 99.2% to 100% (data not shown).
For Pekin ducks, a commercial hybrid and two breeding lines were used as examples of high growth rate birds; these were compared to their ancestral phenotype, the mallard (Anas platyrhynchos).
Then, virtual seasonal bird species distributions were compared to real-world observations for five empirical patterns: 1. richness in breeding migrants (Figure 2a, b, c, d); 2. richness in non-breeding migrants (Figure 2e, f, g, h); 3. richness in residents (Figure 2i, j, k, l); 4. seasonal difference in richness (Figure 2m, n, o, p); and 5. proportion of migrants (Figure 2q, r, s, t).
Each bird's calls were compared using the 6 call parameters listed above and multivariate analysis of variance, MANOVA (SPSS 16.0), to determine whether the variability of sound features between the calls from two groups of birds of different age or sex, for example, were significantly different from each other.
The impact of ASPS on breeding farmland birds was tested in a replicated farm-scale experiment, in which changes in numbers of breeding birds over 5 years were compared between scheme and control farms.
Species composition and diversity of trees and birds among woody habitat islands were compared in a Colombian rangeland to assess how habitat characteristics influence bird community composition, bird species traits and their potential ecosystem services.
When bird inventories from 1970 to 1990 were compared with those from 1990 to 2000, the answer was clear.
