Feather moult and bird appearance are correlated with global warming over the last 200 years.

Global warming alters various avian phenological processes, including advanced reproduction and migration schedules. In birds, individual appearance is largely determined by plumage, influencing, for example, bird attractiveness, social status and camouflage. Juveniles of most passerine species replace their nest-grown plumage during the first months of life, a process that is called post-juvenile feather moult. Using data from ten natural history collections, we show that the extent of the post-juvenile moult has increased significantly over the last 212 years (1805-2016), a trend that is positively correlated with the temperature of the environment. Therefore, it seems that birds replaced more feathers under warmer conditions, causing juveniles to appear more similar to adult birds. Moreover, in several species, we describe a male-female switch in the extent of moult, with females currently replacing more feathers than males compared to the past. These results demonstrate different biological responses to climate warming by different phenotypes.

Migrating birds avoid flying through fog and low clouds.

Different weather conditions are known to affect bird migration, yet the influence of fog and low clouds on migrating birds has been rarely examined so far, and hence, their impact on bird movement is not well understood. Fog avoidance could be a consequence of visual limitations within the fog or may be the outcome of deteriorated soaring conditions due to the obstruction of the sun. We carried out a radar study at the Strait of Messina, which is a bottleneck for migrating birds traversing the Central Mediterranean Sea, to determine if the intensity of diurnal soaring bird migration was influenced by fog and other weather variables. We recorded bird movements using an X-band radar, which can detect birds flying within the fog, and recorded weather conditions using local meteorological observations. We examined if bird passage rate (number of tracks/hour) at the radar site was influenced by fog, wind speed and direction, air temperature and the time of day. Our findings suggest that fog was the most important factor affecting bird migration intensity as recorded by the radar, indicating that birds actively avoided flying into fog. In addition, wind direction affected bird migration intensity, with lower numbers recorded with southerly tailwinds and higher numbers recorded with westerly crosswinds. Our findings highlight a consequence of widespread meteorological conditions, and of fog in particular, on migrating birds, with implications for bird migration navigation, path length and flight energetics.

Effects of inhaled corticosteroids and inhaled cromolyn sodium on urinary growth hormone excretion in asthmatic children.

Over the past few years there has been an increasing awareness that asthma is a chronic inflammatory airways disease. The current therapeutic strategies for treating asthma focus on suppressing the inflammatory process by using cromones or inhaled corticosteroids (ICS). The beneficial effects of ICS in asthma are now well known, but its detrimental effect on linear growth remains a controversial issue. The aim of this open label, nonrandomized, cross-sectional, one-time study was to determine the influence of these drugs on urinary growth hormone (U-GH) levels in prepubertal asthmatic children. U-GH levels were measured in 47 prepubertal asthmatic children who had been treated for at least 6 months with either ICS (beclomethasone or budesonide at a mean daily dose of 360 microg) or with 80 mg daily dose of cromolyn sodium (CrS). There were also nine healthy children who served as a control. These three groups of children were matched for age and gender ratio. The mean level of U-GH in the CrS-treated group was 2.94 +/- 0.96 ng/night; this was significantly higher compared to the mean level of the ICS-treated group (1.99 +/- 0.83 ng/night; P < 0.001) and to the mean level of the control group (1.98 +/- 0.39 ng/night; P < 0.006). There was no significant difference between the mean level of U-GH in the group treated by ICS and the controls (P < 0.9). These results show that the mean levels of U-GH secretion of the children who were treated by CrS for 6 months was significantly increased, compared to the mean U-GH level of the ICS-treated group and the controls. The mean U-GH levels in the last two groups showed no statistically significant difference.