Temporal Changes in Randomness of Bird Communities across Central Europe

Many studies have examined whether communities are structured by random or deterministic processes, and both are likely to play a role, but relatively few studies have attempted to quantify the degree of randomness in species composition. We quantified, for the first time, the degree of randomness in forest bird communities based on an analysis of spatial autocorrelation in three regions of Germany. The compositional dissimilarity between pairs of forest patches was regressed against the distance between them. We then calculated the y-intercept of the curve, i.e. the ‘nugget’, which represents the compositional dissimilarity at zero spatial distance. We therefore assume, following similar work on plant communities, that this represents the degree of randomness in species composition. We then analysed how the degree of randomness in community composition varied over time and with forest management intensity, which we expected to reduce the importance of random processes by increasing the strength of environmental drivers. We found that a high portion of the bird community composition could be explained by chance (overall mean of 0.63), implying that most of the variation in local bird community composition is driven by stochastic processes. Forest management intensity did not consistently affect the mean degree of randomness in community composition, perhaps because the bird communities were relatively insensitive to management intensity. We found a high temporal variation in the degree of randomness, which may indicate temporal variation in assembly processes and in the importance of key environmental drivers. We conclude that the degree of randomness in community composition should be considered in bird community studies, and the high values we find may indicate that bird community composition is relatively hard to predict at the regional scale.

When the prey gets too big: an uncommon road accident involving a motorcyclist, a car and a bird

We present the postmortem findings of a fatal road accident involving a motorcyclist, a car, and a common buzzard. Both the motorcyclist and the bird died on the scene of the accident and were examined by postmortem full-body CT and autopsy. In addition, a facial injury of the motorcyclist was compared with the dimensions of the buzzard’s beak and claws by 3D scan technologies. Blood splatters collected on the bird’s beak, feet, and tail were examined by DNA analysis. The overall findings suggested a collision of a common buzzard with a motorcyclist in full speed, causing the motorcyclist to lose control of his vehicle and crash with an approaching car on the oncoming lane.

Psychotherapieforschung - Ist «Dodo Bird» en vogue?

Das «Dodo-Bird-Verdikt», Ende der achtziger Jahre Resultat einer Metaanalyse, stellte fest, dass sich die etablierten Psychotherapieschulen in ihrer Wirksamkeit statistisch nicht bedeutsam unterscheiden. Der Begriff hat seinen Ursprung in «Alice im Wunderland», wo ein Dodo den Vorschlag macht, ein Rennen zu veranstalten, bei dem am Ende alle gewinnen, weil es kein Ziel gibt und auch die Zeit nicht gemessen wird. – Ist die These unter Akteuren der Psychotherapie en vogue? Ein Kommentar.

Lady-Bird : (Marienkäfer) ; eine Erzählung

von Georgina Fullerton. - Aus dem Engl. von H. Brinckmann

Fine Bird Books

The Department of Special Collections is fortunate to have a number of 19th Century illustrated bird books. These books, filled with hand-colored plates, were produced at a time when there was tremendous interest in the descriptions of new species of birds. At the same time, a new printing technique, lithography, made illustration of new species a simpler process. This combination of art and science resulted in lovely volumes like those on display.

Concentrations of metals and POPs in liver tissue of wild sea bird chicks from the Norwegian arctic region

Lysosomal membrane stability, lipofuscin (LF), malondialdehyde (MDA), neutral lipid (NL) levels, as well as halogenated organic compounds (HOCs), Cr, Cd, Pb and Fe concentrations were analyzed in liver of black-legged kittiwake (BK), herring gull (HG), and northern fulmar (NF) chicks. There were significant species differences in the levels of NL, LF and lysosomal membrane stability. These parameters were not associated with the respective HOC concentrations. LF accumulation was associated with increasing Cr, Cd and Pb concentrations. HG presented the lowest lysosomal membrane stability and the highest. LF and NL levels, which indicated impaired lysosomes in HG compared to NF and BK. Lipid peroxidation was associated with HOC and Fe2+ levels. Specific HOCs showed positive and significant correlations with MDA levels in HG. The study indicates that contaminant exposure can affect lysosomal and lipid associated parameters in seabird chicks even at low exposure levels. These parameters may be suitable markers of contaminant induced stress in arctic seabirds.

Bird observations in the Weddell Sea

Pelagic distribution of birds at the Weddell Sea. The essay contains the notes taken of the observation of birds at the Weddell Sea (24 species). The observations were made on two expeditions in the southern summer of 1955/56 and 1959/60 on board the Argentine icebreaker "General San Martin". After an introduction dealing with the Weddell Sea and the methods of research the species are represented together with the territory of observation and supplementary annotations. Two tables give a survey of the birds seen on each day of the expedition and in the territories they sailed through.