Effects of climate variation on bird escape distances modulate community responses to global change.

Climate and land use are rapidly changing environmental conditions. Behavioral responses to such global perturbations can be used to incorporate interspecific interactions into predictive models of population responses to global change. Flight initiation distance (FID) reflects antipredator behaviour defined as the distance at which an individual takes flight when approached by a human, under standardized conditions. This behavioural trait results from a balance between disturbance, predation risk, food availability and physiological needs, and it is related to geographical range and population trends in European birds. Using 32,145 records of flight initiation distances for 229 bird species during 2006-2019 in 24 European localities, we show that FIDs decreased with increasing temperature and precipitation, as expected if foraging success decreased under warm and humid conditions. Trends were further altered by latitude, urbanisation and body mass, as expected if climate effects on FIDs were mediated by food abundance and need, differing according to position in food webs, supporting foraging models. This provides evidence for a role of behavioural responses within food webs on how bird populations and communities are affected by global change.

Ants Response to Human-Induced Disturbance in a Rain Tropical Forest.

A high rate of human-induced disturbance of tropical ecosystems results in enormous loss of biodiversity due to local extinctions. Yet, mechanisms at the population level that lead to the extinction are still poorly understood. Here we tested the hypothesis that human-induced disturbance results in smaller amount of nesting sites for wood-dwelling arthropods that leads to smaller population size and diminished reproduction, and therefore, may promote local extinctions. We completed censuses in less-disturbed and human-disturbed secondary rain forest plots in Puerto Rico. We measured population size and brood production in wood-nesting ants and examined whether these parameters differ between less-disturbed and more-disturbed habitats. In addition, we measured volume of wood parts of all inhabited and potential nesting sites to assess nest site availability. We found that more human-disturbed forests furnish smaller nest sites, resulting in diminished population size and lowered brood production. Our study shows that human-induced disturbance decreases volume of available nesting sites that leads to decreased population size and lowered reproduction. Thus, in addition to the well-documented loss of species richness in human-disturbed tropical habitats, we demonstrated the direct effect of the disturbance that may promote vulnerability of local populations.

A new species of parasitic mites of the genus Syringophiloidus Kethley 1970 (Acari: Syringophilidae) from the barn swallow Hirundo rustica Linnaeus, 1758.

A new quill mite species Syringophiloidus hirundinis (Acari: Syringophilidae) is described from the Barn Swallow Hirundo rustica. The species Syringophiloidus hirundinis had a prevalence of 17.1% in the two outermost tail feathers (N = 208 adult Barn Swallows) during the breeding season of the Barn Swallow host. Intensity of infestation was 9.7 adult mites per pair of infested tail feathers. The sex ratio was highly biased towards females, with only 7.5% of all individuals being males (20:3).

Two new species of the genus Syringophilopsis Kethley, 1970 (Acari: Syringophilidae) parasitizing quills of true shrikes (Aves: Laniidae).

Two new species of syringophilid mites (Acari: Syringophilidae) are described from quills of true shrikes (Passeriformes: Laniidae): Syringophilopsis kristini sp. n. from Lesser Grey Shrike, Lanius minor, from Slovakia, and Syringophiopsis yosefi sp. n. from Lanius sp. from Cameroun.

Is the detection of the first arrival date of migrating birds influenced by population size? A case study of the red-backed shrike Lanius collurio.

Many analyses do not consider the problems associated with the effects of population size on encounter recording. Population size could impact on the detection of bird arrival time as there is a higher probability of observing earlier arrival when the population size is greater and the song activity of birds is increased, as occurs with a larger population. As a case study, we have analysed data on the red-backed shrike Lanius collurio collected in Western Poland during 1983-2000. In this period the red-backed shrike's return to its breeding sites became significantly earlier whilst the contemporary population size increased significantly. To eliminate linear trends through time we have worked on the standardised residuals from regression of both arrival time and population size on year. The correlation between arrival time and population size residuals was significantly negative, further supporting the link between detection and population size. This finding suggests that, in studies of avian migration and its changes over time, the relationship between arrival date and population size needs to be considered.