Gotowa bibliografia na temat „Willie wagtail”

The insectivorous willie wagtail, Rhipidura leucophrys, exhibits a range of discrete, easily identified foraging behaviours that include wagging the tail and flashing the wing. We investigated whether wagtails adjust these, and other foraging behaviours, according to the time of day and environmental conditions. The rates of tail-wagging and wing-flashing were influenced by the time of day and light intensity. Tail-wagging was more frequent at the start and end of the day, while wing flashing was more frequent during the middle of the day. The rate of aerial prey captures was also highest during the middle of the day and lower in the early morning and late afternoon. These daily patterns of foraging behaviours correspond with the patterns of insect activity, which was greater in the middle of the day than in the early morning or late afternoon. The field data, together with experiments using a model wagtail tail, support the view that tail-wagging and wing-flashing are used to flush insect prey.

Long-term monitoring of bird species provides information on base-line populations and population trends required to ensure that habitat management is effective for their conservation. Two surveys in both spring and autumn over 12 years monitored populations at fixed points in roadside softwood scrub remnants plus adjoining farmland (softwood/farmland) and in eucalypt open forest in south-east Queensland. The main aims were to determine the status of species in each habitat, especially whether the status of any species was changing, and to assess the usefulness of the monitoring procedure. In all, 92 species were observed; 79 in the softwood/farmland and 74 in the eucalypt forest. From 49 to 56 species were observed each year in softwood/farmland and 34 to 46 in eucalypt forest. Annual species turnover in softwood/farmland was about half that in eucalypt forest; 39% of all species were observed every year in the former habitat, but only 19% in the latter. The Torresian Crow was most often observed in softwood/farmland and the Noisy Miner in eucalypt forest. The Torresian Crow was the only species to be among the five most observed in each habitat. Among other common species, 95% or more observations of Bar-shouldered Doves, Superb Fairy-wrens, Yellow Thornbills and Silvereyes were in softwood/farmland, whereas for Weebills, White-throated Gerygones, Buff-rumped Thornbills, White-throated Treecreepers and White-throated Honeyeaters at least 95% of observations were in eucalypt forest, confirming their strong habitat specificities. The number of birds observed increased linearly for eight species in softwood/farmland and six species in eucalypt forest, and decreased for five and four species, respectively, over the 12 years. The most significant trends were for the Crested Pigeon (increase) and Willie Wagtail (decrease) in softwood/farmland, while Peaceful Dove and Rufous Whistler decreased in both habitats. Several species which increased adapt well to partial clearing of woody vegetation and aggressively exclude others, e.g., Noisy Miner, butcherbirds and Pied Currawong. The trends may reflect insidious degradation of habitats. The main value of the survey method was for detecting changes of species that could be used as indicator species ? those that respond most rapidly to habitat change. While the method was efficient, wildlife managers would need to use it regularly to maintain skills, especially because most observations are of bird calls.

Abstract Although flight initiation distance (FID) has been shown to be shorter in urban compared to rural populations of birds, less is known about how the characteristics of the urban environment, such as the population size and age of the city influences the FID and other aspects of anti-predator behaviour. Urban willie wagtails and magpie larks in a relatively small and new town had shorter FID than rural conspecifics. Both species were more likely to show a short, rather than long, escape flight if the experimenter started walking towards the bird from further away. There was some indication that urban birds may be more likely to show a short escape flight than rural birds. We conclude that anti-predator responses of birds can be influenced by a relatively small, recently established and sparsely-populated town. Additionally, the possibility of the characteristics of the urban centre influencing variation in the FID response is discussed.

Habitat use by birds in suburbs of Brisbane, Queensland was studied during winter, at sites with relatively similar habitat features near to (0.25-0.5km) and far from (2-3km) a eucalypt forest. Variation in other factors was restricted. Distance from native forest was found to have little influence on abundance of birds in suburban habitats. House sparrows and willie wagtails were relatively more abundant at the far sites. Most of the more common forest-dwelling species were not common in either near or far suburbs. There was little similarity in relative abundance of bird species between the forest and either the near or far suburbs. A similarity in species diversity and positive correlations in species abundance between near and far sites indicate that most species are either forest or suburb 'specialists'. Native birds were more selective in their choice of plant category than introduced birds, and had a high probability of using certain native and exotic plant species, and a lower probability of using others. Although generally more abundant, introduced birds did not have a high probability of using any plant genus or type. Birds in the area studied are probably altering their patterns of habitat use in response to changes in food availability.

[Truncated abstract] The identification of individual animals based on acoustic parameters is a non-invasive method of identifying individuals with considerable advantages over physical marking procedures. One requirement for an effective and practical method of acoustic individual identification is that it is call-independent, i.e. determining identity does not require a comparison of the same call or song type. This means that an individuals identity over time can be determined regardless of any changes to its vocal repertoire, and different individuals can be compared regardless of whether they share calls. Although several methods of acoustic identification currently exist, for example discriminant function analysis or spectrographic cross-correlation, none are call-independent. Call-independent identification has been developed for human speaker recognition, and this thesis aimed to: 1) determine if call-independent identification was possible in birds, using similar methods to those used for human speaker recognition, 2) examine the impact of noise in a recording on the identification accuracy and determine methods of removing the noise and increasing accuracy, 3) provide a comparison of features and classifiers to determine the best method of call-independent identification in birds, and 4) determine the practical limitations of call-independent identification in birds, with respect to increasing population size, changing vocal characteristics over time, using different call categories, and using the method in an open population. ... For classification, Gaussian mixture models and probabilistic neural networks resulted in higher accuracy, and were simpler to use, than multilayer perceptrons. Using the best methods of feature extraction and classification resulted in 86-95.5% identification accuracy for two passerine species, with all individuals correctly identified. A study of the limitations of the technique, in terms of population size, the category of call used, accuracy over time, and the effects of having an open population, found that acoustic identification using perceptual linear prediction and probabilistic neural networks can be used to successfully identify individuals in a population of at least 40 individuals, can be used successfully on call categories other than song, and can be used in open populations in which a new recording may belong to a previously unknown individual. However, identity was only able to be determined with accuracy for less than three months, limiting the current technique to short-term field studies. This thesis demonstrates the application of speaker recognition technology to enable call-independent identification in birds. Call-independence is a pre-requisite for the successful application of acoustic individual identification in many species, especially passerines, but has so far received little attention in the scientific literature. This thesis demonstrates that call-independent identification is possible in birds, as well as testing and finding methods to overcome the practical limitations of the methods, enabling their future use in biological studies, particularly for the conservation of threatened species.

We repair to the coffee-house, where we overhear a curious dispute between Wagtail and Medlar, which is referred to our decision——the doctor gives us an account of his experiment—Medlar is roasted by Banter, at the ordinary—the old gentleman’s advice to me Being as willing...