1. Currently, the deployment of tracking devices is one of the most frequently used approaches to study movement ecology of birds. Recent miniaturization of lightlevel geolocators enabled studying small bird species whose migratory patterns were widely unknown. However, geolocators may reduce vital rates in tagged birds and may bias obtained movement data.2. There is a need for a thorough assessment of the potential tag effects on small birds, as previous meta-analyses did not evaluate unpublished data and impact of multiple life-history traits, focused mainly on large species and the number of published studies tagging small birds has increased substantially.

No abstract

Incubation behaviour of the Meadow Pipit (Anthus pratensis) was investigated in mountainous conditions in Central Europe (the Krkonoše Mountains of the Czech Republic), in relation to the time of day and weather. Twenty-four-hour recordings of incubation behaviour were made with a time-lapse video recorder and mini-camera. The influences of year, nest, time of day, temperature, precipitation and previous bouts on session and recess duration were then analysed. The incubation behaviour of Meadow Pipits in general did not differ from the behaviour of other small female-only incubating passerines. Despite relatively cold climatic conditions in the study area, the mean length of sessions and recesses (19.69 and 5.53 min), as well as nest-attentiveness (77.19%), agreed with values which are most often found in other species. However, the Meadow Pipit incubation in the study area was, in terms of nest-attentiveness, more intensive than in other surveyed populations of this species. Incubation behaviour was strongly influenced by the time of day-incubating females increased nest-attentiveness during the morning and evening hours. After the time of day was filtered out, the influence of temperature was found only on sessions (not recesses). Sessions were the longest when the air temperature was approximately 12-16°C and shortened when the temperature was lower or higher. Precipitation forced female Meadow Pipits to take longer sessions and shorter recesses, which corresponds to their general tendency to give priority to the needs of the clutch ahead of their own temporary feeding needs.

The larvae of blow fly (Trypocalliphora braueri) are known to cause a subcutaneous myiasis in bird nestlings mainly in Nearctic species, while only a few records are available from the Palaearctic. Here, we report on infestations of this insect ectoparasite in two passerine species, Meadow Pipit (Anthus pratensis) and Bluethroat (Luscinia svecica), breeding in the Central European mountain range Krkonoše. The infestation of T. braueri parasite was relatively low in studied bird species (3.0% of infested nests in Meadow Pipit and 4.2% in Bluethroat) but varied strongly between years (0-33% of infested nests/ year/species). The presence of the parasitic blow fly larvae was apparently controlled by temperature; they were found only during warm summers. The combination of parasite infection and heavy rainfalls in a critical period significantly reduced nestling survival.

Differences in vocalization between subspecies of songbirds may influence intraspecific interactions including mate choice and territorial behavior, and contribute to their further divergence by strengthening premating reproductive isolation. We have recently shown that songs of two Bluethroat subspecies, Luscinia svecica svecia and L. s. cyanecula, differ in spectral characteristics and structure. Here, in a first experimental test of whether these differences are biologically relevant, we compared responses of L. s. svecica males to both types of songs. Altogether 19 males from a subartic population in Abisko, Sweden, were exposed to playbacks of songs from the two subspecies, accompanied by display of a stuffed Bluethroat lacking subspecies-specific colour marks. These stimuli were presented in random order, separated by over 1 h. We evaluated two largely uncorrelated components of male responses: non-vocal territorial behavior, and singing activity. A significant difference in reaction to subspecies playbacks was observed in aggressive behavior: independently of the song order, males generally responded more strongly to playback of their own subspecies. In contrast, playback order rather than subspecies identity significantly influenced the singing activity, which usually increased in the second trial. A more detailed analysis nevertheless suggested that vocal responses of birds exposed first to playback of their own subspecies were stimulated in the subsequent trial but not vice versa. Our results show that Bluethroats clearly discriminate the two song types, indicating the potential for subspecies recognition. Further experimental work is needed to assess the general validity of these patterns.