"If you really want to understand color, we must do studies of the birds!" The effect Utzon wanted was "a climax in color" that would "uplift you in that festive mood, away from daily life, that you expect when you go to the theatre".
In birds the effect of load carriage during terrestrial locomotion has been studied in only two species; guinea fowl, Numida meleagris, (Marsh et al., 2006; McGowan et al., 2006) and the barnacle goose, Branta leucopsis (Tickle et al., 2010).
This result was not seen in control birds, so the effect was likely caused by exposure to enrichment objects.
While the population impacts of acute and chronic lead exposure are unknown for most wild bird populations, the effect of lead exposure on long-term sustainability through direct mortality and sublethal effects is a concern.
Although this type of reasoning could also apply to species where the females are heterogametic (certain insects, fish, reptiles and birds), this effect of the process would be somehow restricted by the fact that females are, by nature, restricted in the number of eggs, and hence offspring that they can generate.
With more than 330 million observation on birds from around the world, the eBird project yields new insights and data-intensive visualizations on the distribution and abundance of birds and the effects of environmental change.
A study of the outbreak in Chicago in 2002 indicated that human disease cases tended to occur in areas with more vegetation, older housing, lower population density, predominance of older Caucasian residents, and proximity to dead birds, but the effects of these variables were influenced by differences in mosquito abatement efforts (14).
The only formal study of the birds' effect on the crawfish ponds was done in 1985 by Richard Martin, who is now director of conservation programs for the state Nature Conservancy.
Effects were seen only in adults, not in juvenile migratory birds, suggesting that the effect was on an experience-based system such as a geomagnetic 'map' rather than on the compass.
This principle describes the phenomenon occurring in both mammals and birds in which the effect of adding an additional modality to a stimulus on response magnitude is inversely proportional to the original salience of the stimulus when presented alone [22], [23], [24].
It should be noted that our study and the abovementioned studies on birds have investigated the effect of maternally derived steroids on digit ratio development and other phenotypic and behavioral correlates.
