Thesis (Ph.D.) - University of St Andrews, April 2010.

No description available.

The timing of many biological events, including the onset of spring and bird migration, have changed in the recent years due to climate change. This may affect birds’ length of stay in the breeding area. By using Swedish ringing data from two periods, 1979-1989 and 2006-2016, changes in the length of stay between birds with different migration modes and seasonal number of broods were analysed. The results indicated that changes in the length of stay differed between species depending on their seasonal number of broods. Species with a fixed number of broods shifted their stay by arriving earlier in the spring and migrating earlier in the fall. In contrast, species with a variable number of broods extended their stay by arriving earlier in the spring without changing the timing of autumn migration. An extended stay might enable a higher reproduction output by giving the opportunity to invest more time in offspring. Thus, climate change might favour species with a variable number of broods. Birds with a fixed number of broods might however not experience the same benefits of a warmer climate because their annual reproductive success often relies on one single brood. Species with a fixed number of broods are generally long-distance migrants and therefore their migration is less flexible. If they do not arrive early enough to match their breeding with the advanced timing of peak food abundance a mismatch arises. As a result, they might be more sensitive to climate change

No description available.

Hintergrund Turbulente Zeiten in der Arktis. Um die in der Arktis vorherrschenden meteorologischen Prozesse besser verstehen zu können, sind wissenschaftliche Forschungen in diesem Gebiet von großer Bedeutung. Ein wichtiger Bestandteil dieser Forschungen ist die Untersuchung der Grenzschicht. Der Aufbau dieser wird durch die in der Grenzschicht ablaufenden Transport- und Austausch-prozesse gekennzeichnet. Um diese näher untersuchen zu können, wurde am Alfred-Wegener-Institut in Bremerhaven eine Messsonde entwickelt, der T-Bird. Hierbei handelt es sich um einen Schleppkörper, der im Zusammenhang mit einem Trägerflugzeug zum Einsatz kommt. Die Mess-sonde ist dabei über ein Seil mit dem Trägerflugzeug verbunden. Dies erlaubt Messflüge in ger-ingen Höhen. Da der T-Bird keine Tragflächen besitzt, kann er nur im Zusammenhang mit einem weiteren Luftfahrzeug betrieben werden. Die Flugdynamik und die Flugstabilität des Schleppkörpers stehen somit im direkten Zusammenhang mit denen des Trägerflugzeuges. So werden auftretende Bewegungen des Flugzeuges zwangsläufig über das Seil an den T-Bird weitergeleitet. Inhalt der Arbeit Diese wissenschaftliche Arbeit betrachtet vorrangig das Flugverhalten der Messsonde T-Bird. Dafür wurden theoretische Abschätzungen zu den Flugeigenschaften und dem auftretenden Pen-delverhalten des T-Birds getroffen. Anschließend erfolgte ein Vergleich zwischen den theoretischen Abschätzungen und den im November 2021 aufgenommenen Messdaten während der Testflüge des T-Birds über der Nordsee. Aus den Messdaten der verbauten wissenschaftlichen Geräte (Lagedaten, Druckmessung, Videoaufzeichnung) wurden die Pendelbewegungen der Messsonde am Schleppseil verdeutlicht. Diese äußern sich u. a. im Schiebe- und Gierwinkel. Ab-schließend konnte eine Bewertung zur Vermeidung des Pendelverhaltens vorgenommen werden, um zukünftig ungestörte Messungen durchführen zu können.

Det sker stora förändringar i de regional likt globala fågelbestånden. I Sverige sker både ökningar och minskningar av populationerna, vilket orsakas av flera olika faktorer. En av dessa är tillgången på föda. Därför är syftet med denna studie att undersöka om avslutad fågelmatning någon påverkan på ett lokalt fågelbestånd.Fågelsamhället på Fredriksdals museer och trädgårdar i Helsingborg studerades medstandardiserade revirkarteringar med en anpassad linjekartering av området under perioden 2017–2022. De faktorer som undersöks är förhållandet mellan de arter som förekommer vid matning eller ej, förhållandet mellan stann- och flyttfåglar samt utvecklingen av det totala antalet arter och par under undersökningsperioden. Resultatet visar att det totala antalet fåglar på Fredriksdal minskat med 50% under de senaste sex åren medan antalet arter varit stabilt. Det observerades ingen signifikant skillnad i minskningen av de fåglar som förekommer vid matning och gruppen som inte förekommer vid matningen. Det fanns inte heller någon signifikant skillnad mellan minskningen av de övervintrande fåglarna och flyttfåglarna. Dessa båda grupper visade en stabil negativ trend över undersökningsperioden. Detta betyder att den upphörda fågelmatningen kan ha påverkat bestånden negativt men det är isfallbara för enskilda arter och det kan inte förklara den totala minskningen. Några delförklaringar till den negativa trenden är klimatförändringarna som på global nivå påverkar fågelbestånden, förändringar i habitat både på Fredriksdal och på flyttfåglarnas övervintringslokaler och minskad tillgång på föda främst på grund av det minskande antalet insekter i hela Europa. / There are major changes in regional as well as global bird populations. In Sweden, there are both increases and decreases in populations, which is caused by several different factors. One of these is the availability of food. Therefore, the purpose of thisstudy is to investigate whether completed bird feeding at Fredriksdal's museums and gardens in Helsingborg has any impact on the local bird population. The method used is standardized area mapping with an adapted line mapping of the area during the period 2017–2022. The factors investigated are the ratio between the species that occur when feeding or not, the ratio between resident and migratory birds and the development of the total number of species and pairs during the study period. The result shows that the total number of birds at Fredriksdal has decreased by 50% over the past six years, while the number of species has remained stable. No significant difference was observed in the reduction of the birds present at feeding and the group not present at feeding. There was also no significant difference between the decline of wintering birds and migratory birds. These two groups showed a stable negative trend over the survey period. This means that the cessation of bird feeding may have had a negative effect on the populations, but it is icefall only for individual species and it cannot explain the overall decline. Some partial explanations for the negative trend are the climate changes that affect bird populations on a global level, changes in habitat both at Fredriksdal and at the migratory birds' wintering grounds as well as reduced availability of food mainly due to the decreasing number of insects throughout Europé.

As the breeding bird communities and population numbers have not been widely studied in Lithuania, there is not much local literature on the subject. Traditionaly for decades more attention was given to the migrating birds in Lithuania. From 1995 the Lithuanian Ornithological Society have been systematically making bird breeding population survey when usung point count methodology. This was the first attempt to computer and analyze the data of the point count studies made by the Lithuanian Ornithological Society in 1996-2004. During the point count survey 158 species of birds were recorded. Among them the Passeriformes species predominate. Our observations shows that Fringilla coelebs, Erithacus rubecula predominantes in the forested landscapes. Alauda arvensis and Sturnus vulgaris are predominating in bird communities assciations in the agricultural landscape. Numbers of local breeding populations were fluctuating mostly among years but were near stable during the period. Local populations of Anthus trivialis and Carduelis chloris have increased in minimum 20%. At the some time local breeding populations of Carduelis carduelis and Sturnus vulgaris have decreased in minimum 20%.

The decline in range and density of many native New Zealand birds from mammalian predation has raised concerns over the functioning of ecosystem processes such as pollination and seed dispersal. At Maungatautari, almost all mammalian pests have been eradicated from within a pest-proof fence enclosing 3400 ha of native forest. I examined whether Maungatautari is restoring pollination and seed dispersal services to native plants, compared to a nearby non-treatment site, Pirongia Mountain. Five-minute bird counts made at Maungatautari and Pirongia (in 2002 and 2005 prior to pest eradication from Maungatautari, and in 2008 and 2010 following eradication) indicated that 10 of the 12 individual bird species examined showed significant changes in abundance following pest control. Six species showed an increase in abundance, including bellbirds (Anthornis melanura), tui (Prosthemadera novaeseelandiae) and kereru (Hemiphaga novaeseelandiae). Counts of all native species combined increased at Maungatautari while counts of all exotic species showed no trend over count years. In December 2010, 140 five-minute bird counts showed tui and bellbirds, key pollinators, to be more abundant at Maungatautari than Pirongia. Higher pollen loads on the stigmas of both female and hermaphrodite Fuchsia excorticata flowers at Maungatautari, compared to Pirongia, suggest that F. excorticata at Maungatautari received better pollination service. Fuchsia excorticata pollen loads collected from 67 sites around New Zealand indicate that female plants at sites with lower abundances of mammalian predators generally received better pollination service. Hermaphrodite F. excorticata plants had similar and high pollen scores in all regions, except for in the North Island. Five-minute bird counts in December 2010 also showed that kereru and blackbirds (Turdus merula), key seed dispersers along with tui and bellbirds, were more abundant at Maungatautari than Pirongia. A second measure of bird abundance, maximum counts, showed flock sizes of tui, bellbirds and kereru were larger at Maungatautari, but only significantly so for tui and bellbirds. Fuchsia excorticata fruits were removed more rapidly from plants at Maungatautari than at Pirongia (a 6-fold difference). There was twice the density of tawa fruits (bird cleaned and fleshy) under trees at Maungatautari compared to Pirongia, perhaps from reduced mammalian fruit predation. There was no significant site effect on tawa dispersal service (percent of fruit consumed by birds), but a significant site x fruit density interaction, suggests birds at Maungatautari provided better dispersal service to large fruit crops. A similar number of miro fruit (bird cleaned and fleshy) were caught in seed traps under miro trees, but a greater percentage of fruits were consumed by birds at Maungatautari (59%) compared to Pirongia (26%). The results from this thesis indicate that increased densities of key native birds at Maungatautari are providing better pollination and dispersal services to the native plants examined. Projects which increase the density of key bird mutualists, such as tui, bellbirds and kereru, on the mainland, may have positive benefits for pollination and seed dispersal mutualisms.

Tato diplomová práce se zabývá problematikou plašení ptáků a jejich humánního plašení pomocí laserů. Práce také pojednává o bezpečnosti laserů, problému řídicího obvodu laserových diod, kolimaci svazku a jeho rozšíření tak, aby výstupní výkon paprsku nepřekročil maximální hodnotu výstupního výkonu laseru třídy 2M.

Wind is the second largest renewable energy source after solar. It is one of the fastest growing sources of electricity in the world and currently of wind energy is installed in the United States and an additional is under construction (Office of Energy and Environment Affairs, 2011). For the growth of wind electricity, one of the most prominent environmental concerns relates to the death of birds, bats and other avian species resulting from collision with turbine blades. This thesis develops a model that provides the optimal strategy of turning the turbines off in a wind farm for certain periods to mitigate bird mortalities. We first create a single turbine optimization model for each hour on each day of a single month. We maximize the expected revenue generation and limit the expected bird mortalities to a certain level to solve for the dates and times for which the turbine should be turned off. The optimization problem is found to be part of common class of problems called Knapsack problems and through experiments we conclude that a linear programming (LP) relaxation of the problem provides a near-optimal solution. We extend the single-turbine model to a multiple-turbine model applicable to a wind farm. In this case, we solve for the percentage of wind turbines that should be turned off to limit the expected bird mortalities to a certain level. Finally, we carry out an uncertainty analysis and estimate probability distributions over the outcome of optimal strategy of turning the turbine off. We consider the Cape Wind project as a case study and limit the analysis to only one species of endangered birds called the common loon. We find that in order to save an expected number of 10 such birds in the month of March; we need to turn the turbine off for a total of 23 hours spread over specific dates and times. The average cost per bird was found to be $171.